#Hantavirus #cluster linked to cruise ship travel, Multi-country (#WHO D.O.N., May 13 '26)

 

Situation at a glance

    -- This is the third Disease Outbreak News report on the hantavirus cluster, following the notification to the World Health Organization (WHO) on 2 May 2026 of severe respiratory illness cases aboard MV Hondius, a cruise ship. 

    -- Since the last DON was published on 8 May, two additional confirmed cases were reported from France and Spain. 

    -- In addition, there is one inconclusive result for a case in the United States of America. 

    -- All were passengers on the ship. 

    -- As of 13 May, a total of 11 cases, including three deaths, have been reported (case fatality ratio 27%). 

    -- Eight cases were laboratory-confirmed for Andes virus (ANDV) infection, two are probable, and one case remains inconclusive and undergoing further testing. 

    -- Through the International Health Regulations (2005) (IHR) channels, National IHR Focal Points (NFPs) have all been informed and are supporting international contact tracing efforts. 

    -- WHO has assessed the risk posed by this event to the global population as low and will continue to monitor the epidemiological situation and update the risk assessment as needed.

Description of the situation

    -- On 2 May 2026, WHO received notification from the IHR NFP of the United Kingdom of Great Britain and Northern Ireland (hereafter referred to as the United Kingdom) regarding a cluster of severe acute respiratory illness, including two deaths and one critically ill passenger, aboard the Dutch-flagged cruise ship MV Hondius.

    -- As of 13 May, a total of 11 cases (eight confirmed, one inconclusive and two probable cases), including three deaths (two confirmed and one probable), have been reported. 

    -- Since the last Disease Outbreak News was published on 8 May, two additional confirmed cases and one inconclusive case have been reported among passengers. 

    -- These are one confirmed case from France, who became symptomatic during repatriation, one confirmed case from Spain, tested upon arrival following repatriation but currently well and asymptomatic, and one case considered inconclusive. 

    -- The latter was repatriated to the United States of America, is currently asymptomatic with inconclusive laboratory results (one positive and one negative result from two different laboratories), and is being retested. 

    -- The individual was sampled due to high-risk exposure to confirmed cases on board.  

    -- All laboratory-confirmed cases are confirmed for ANDV infection. 

-- All were passengers onboard the MV Hondius. 

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Figure 1. Epidemiological curve of Andes hantavirus cases (n = 11) reported to WHO as of 13 May 2026, 17:00. 

{Click on Image ot Enlarge}

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    -- Based on currently available information, the working hypothesis is that the first case acquired the infection prior to boarding the cruise, through exposure on land. 

    -- Investigations are ongoing to elucidate the potential circumstances of exposure and the source of the outbreak, in collaboration with authorities in Argentina and Chile. 

    -- Current evidence suggests subsequent human-to-human transmission onboard the ship. 

    -- This is also supported by a preliminary analysis of the sequences, which show a close, near-identical sequenced from different cases.[1]

    -- The outbreak is being managed through a coordinated international response, including: 

    ° in-depth epidemiological investigations, 

    ° case isolation and clinical management, 

    ° medical evacuations, 

    ° laboratory testing and international contact tracing, 

    ° quarantining and monitoring. 

    -- Recommendations may be updated as additional epidemiological and laboratory evidence, including genetic sequencing data, becomes available.

    -- Follow-up and contact tracing for all contacts of hantavirus cases linked to the cruise ship is ongoing. 

    -- This includes passengers who disembarked in Saint Helena, United Kingdom, on 24 April; Praia, Cabo Verde, on 6 May; and Tenerife, Spain, on 10 and 11 May. 

    -- Passengers who travelled on flights who may have had exposure to subsequently confirmed cases have been identified and contacted. 

    -- Contacts are being monitored by local health authorities in their respective countries.  

    -- On 10 May, the ship arrived in the Canary Islands, Spain, where disembarkation began.  

    -- Passengers and most of the crew were repatriated from the Canary Islands to their respective residence countries or transit points via specially arranged non-commercial flights, with WHO and partners supporting the disembarkation process. 

    -- The ship left the Canary Islands on 11 May and is sailing to the Netherlands, with 25 crew members remaining on board, along with two Dutch health and care workers to conduct their health monitoring and provide any healthcare that may be necessary. 

Epidemiology

    -- Hantavirus cardiopulmonary syndrome (HCPS), also known as hantavirus pulmonary syndrome (HPS), is a zoonotic, viral respiratory disease caused by hantaviruses of the genus Orthohantavirus, family Hantaviridae, order Bunyavirales. 

    -- More than 20 viral species have been identified within this genus.  

    -- Hantaviruses are associated with two major distinct clinical syndromes in humans: HPS predominantly reported in the Americas, and hemorrhagic fever with renal syndrome (HFRS), mainly reported in Europe and Asia. 

    -- However, human-to-human transmission has only been reported for HPS associated with Andes virus infection. 

    -- Andes virus is endemic in South America, with confirmed circulation and human cases reported primarily in Argentina and Chile, and additional cases and related strains identified in Uruguay, southern Brazil, and Paraguay.

    -- Human Hantavirus infection is primarily acquired through contact with the urine, faeces, or saliva of infected rodents or by touching contaminated surfaces. 

    -- Exposure typically occurs during activities such as cleaning buildings with rodent infestations, though it may also occur during routine activities in heavily infested areas. 

    -- Human cases are most commonly reported in rural settings, such as forests, fields, and farms, where rodents are present, and opportunities for exposure are greater.

    -- HPS is characterized by headache, dizziness, chills, fever, myalgia, and gastrointestinal symptoms, such as nausea, vomiting, diarrhoea, and abdominal pain, followed by sudden onset of respiratory distress and hypotension. Symptoms of HPS typically occur from 1-6 weeks after initial exposure to the virus. However, symptoms may appear as early as one week and as late as eight weeks following exposure.

    -- Hantavirus infections are relatively uncommon globally.  In 2025, in the Region of the Americas, eight countries reported HPS, 229 cases and 59 deaths with a CFR of 25.7%.[2] 

    -- HPS is not reported in other parts of the world. 

    -- In the European Region, 1885 hantavirus infections causing HFRS were reported in 2023 (0.4 per 100 000), marking the lowest rate observed between 2019 and 2023.[3] 

    -- In East Asia, particularly China and the Republic of Korea, HFRS continues to record thousands of cases annually, although incidence has declined in recent decades.

    -- The overall CFR for HPS can be as high as 50%. While there are no licensed treatment nor vaccines for hantavirus infections, early supportive care and immediate referral to a facility with a complete ICU can improve survival.

    -- Environmental and ecological factors affecting rodent populations can influence disease trends seasonally. Since hantavirus reservoirs are sylvatic rodents, transmission can occur when people come into contact with rodent habitats.

    -- Although uncommon, limited human‑to‑human transmission of HPS due to Andes virus has been reported in community settings involving close and prolonged contact. 

    -- Secondary infections among healthcare workers have been previously documented in healthcare facilities, though remain rare. 

    -- Secondary transmission appears most likely during the early phase of illness, when the virus is more transmissible. 

    -- Currently, little evidence is available due to the scarcity of hantavirus outbreak related to human-to-human transmission.

Public health response

    -- Authorities from States Parties managing cases and/or contacts, WHO, and partners have initiated coordinated response measures, including:

    ° Ongoing engagement between WHO and the NFPs of countries managing cases and/or contacts to ensure timely information sharing and coordination of response actions.

    ° International contact tracing is ongoing.

    ° WHO is requesting regular information sharing and periodic updates from States Parties through IHR channels regarding contact monitoring and the health status of high-risk contacts

    ° Crew members still onboard, to take the MV Hondius to the Netherlands, have been advised to practice physical distancing and remain in their cabins where possible, while on the cruise ship.

    ° Experts from WHO and the European Centre for Disease Prevention and Control (ECDC) were deployed on board the ship to support epidemiological investigation and provide public health advice before disembarkation in the Canary Islands, Spain.

    ° Two Dutch medical doctors boarded the ship in Cabo Verde to conduct health monitoring and provide any health care that may be necessary. One disembarked in Tenerife, while a Dutch nurse boarded, to assist in monitoring and providing any healthcare to the remaining crew members on board.

    ° WHO Director-General Dr Tedros Adhanom Ghebreyesus travelled to the Canary Islands on 9 May, along with other experts from WHO, to meet with the national authorities, including ministers, and support the coordination of the operations. He met with the Prime Minister of Spain on 12 May.[4]

    ° Epidemiological investigations continue to better define epidemiological links between cases and exposure factors on the ship, as well as to try to understand the potential source of exposure

    -- WHO has developed and published specific technical guidance documents to support response to the event, including:

    ° Technical guidance on the management of hantavirus on board the ship;

    ° Technical note for the disembarkation and onward management of passengers and crew in the context of an Andes-virus-associated cluster;

    ° Management of contacts of Andes Virus (ANDV) cases from the MV Hondius cruise ship

    -- NFPs of affected countries have been in contact about passenger and crew information through established IHR channels for those on the ship, as well as on planes where a known case was on board.

    -- The NFP of Argentina aided in the reconstruction of the travel itinerary of the first two cases in the Southern Cone subregion of the Americas and assess any potential exposure to hantavirus. They also shared the National Hantavirus Epidemiological Circular: Update epidemiological Surveillance and Management Standards on Hantavirus. 

    -- WHO supported collaboration across relevant laboratories with prior experience to ensure timely testing, with further analyses ongoing, including serology, molecular diagnostics, sequencing, and metagenomics.

    -- Risk communication coordination and support are being provided to ensure sharing of regular, timely and evidence-based information. WHO has activated three-level coordination and is supporting national authorities in implementing risk-based, evidence-informed public health measures in accordance with the provisions of the IHR and related WHO technical guidance documents.

    -- WHO regularly convenes expert calls across laboratory, clinical management, epidemiology, and Infection prevention and control (IPC) domains to facilitate timely experience sharing and coordinated expert support.

    -- WHO supported the streamlining and development of research protocols on the natural clinical history in collaboration with national partner institutions and planned a hantavirus scientific consultation on medical countermeasures.

WHO risk assessment

    -- WHO currently assesses the public health risk for those who were onboard the cruise ship as moderate, and at the Global level as low for the following reasons:

    ° Andes virus has demonstrated limited human-to-human transmission in previous outbreaks, typically occurring among close contacts and within household settings, generally requiring prolonged close exposure. Transmission can be contained through early detection, isolation of cases, clinical management, and contact management. However, the ship environment presented an increased risk due to close living quarters, shared indoor spaces, prolonged exposure, and frequent interpersonal interactions, all of which likely facilitated transmission.

    ° The HCPS with hantaviruses in the Americas, including Andes can have a high case fatality ratio, reaching 40-50%, particularly among elderly individuals and those with co-morbidities. The average age of passengers on board the ship was 65 years old.

    ° Investigations on the travel history and potential exposures of the first case in the Southern Cone subregion of the Americas are ongoing and suggest possible exposure to rodents during bird watching activities. Viral sequencing analyses are also ongoing and will compare the ANDV strain associated with this outbreak with strains circulating in Argentina and Chile, where the disease is enzootic. The preliminary sequencing analysis for the cases indicates a high degree of genetic similarity—showing no more than one single nucleotide polymorphisms (SNP) difference per individual—strongly indicates that the outbreak likely arose from a single zoonotic spillover event, or from a very small number of closely related spillover events.[1]

    ° Additional cases may occur among individuals exposed before implementation of containment measures. However, the current response, including quarantine for those who have left the ship and rapid isolation of any new suspect cases and the monitoring of contacts, is expected to limit the risk of further spread.

    ° As there is no specific antiviral treatment for HPS, suspected cases require prompt transfer to an adequately equipped emergency department or intensive care unit, where available, for close monitoring and supportive management to improve chances of recovery. Consequently, for remote areas, rapid transfer to a mainland healthcare facility is required, which may be challenging under the current conditions.

    ° For the general public, including people not exposed on board the ship or through close contact with a confirmed case, the overall probability of infection remains low. Current evidence indicates that transmission occurs through close and prolonged contact, and can be effectively limited through early detection, isolation of cases, and contact tracing.

    -- More detailed epidemiological, clinical and laboratory investigations are required to inform further iterations of this risk assessment. 

WHO advice

    -- WHO advises that States Parties involved in this event continue public health coordination and management efforts related to the ship and relevant flights, and in countries where cases and/or contacts are present or will be returning to. 

    -- Based on information available and ongoing epidemiological, clinical and environmental investigations, and applying the precautionary principle, this includes: 

    ° contact tracing and monitoring, 

    ° detection, investigation, reporting of suspected cases, 

    ° laboratory testing of suspected cases, 

    ° case management, 

    ° infection prevention and control measures, and 

    ° clear and transparent communication to affected individuals and the general public.

    -- Outside the context of the ship, high-risk contacts may include intimate partners, household members and persons with prolonged close indoor exposure, healthcare workers with unprotected exposure, and individuals handling contaminated materials or body fluids without appropriate personal protective equipment, outlined in the interim guidance published on 8 May. 

    -- Given that infectiousness peaks in the early phase of illness, and that pre-symptomatic transmission cannot be entirely ruled out, as a precautionary principle, WHO recommends active monitoring and home or facility quarantine of high-risk contacts for 42 days following last exposure. 

    -- Current evidence does not support routine laboratory testing of contacts for outbreak control nor the quarantine of low-risk contacts; low-risk contacts should undertake passive self-monitoring and seek medical evaluation if symptoms occur. Recommendations are dynamic and will be adapted as more evidence emerges.

    -- Contact investigations should use available information sources, including interviews, passenger manifests, seating arrangements and activity logs, to improve completeness of contact identification.

    -- Early recognition of suspected cases, prompt isolation, and consistent adherence to recommended infection prevention and control measures remain essential to protect healthcare personnel, other passengers and crew members.

    -- In healthcare settings:

    ° Apply standard precautions* at all times for all patients, including hand hygiene, environmental cleaning, and waste management.

    ° Isolate any suspected or confirmed case in a single, well‑ventilated room with doors closed.

    ° Implement transmission‑based precautions in addition to standard precautions for suspected or confirmed cases.

    ° Ensure health and care workers wear appropriate personal protective equipment (respirators, eye protection, gowns, and gloves).

    ° Perform hand hygiene before and after the use of personal protective equipment.

    ° Manage waste generated from suspected or confirmed cases as infectious waste.

    ° Apply airborne precautions during aerosol‑generating procedures.

    -- When HPS is suspected, patients should be promptly transferred to an emergency department or intensive care unit for close monitoring and supportive management. 

    -- Initial management should include supportive care with antipyretics and analgesics as needed. 

    -- For confirmed hantavirus, antibiotics are not routinely indicated. However, before a definitive diagnosis is established (and bacterial infection is a diagnostic possibility), or if secondary bacterial infection is suspected, empiric broad-spectrum antibiotics may be appropriate. 

    -- Clinical management relies primarily on careful fluid administration, hemodynamic monitoring, and respiratory support. 

    -- Given the rapid progression of HPS, close monitoring and early transfer to ICU are critical for more severe cases. 

    -- Mechanical ventilation, judicious fluid management, and vasopressors may be required. 

    -- For severe cardiopulmonary insufficiency, extracorporeal membrane oxygenation may be lifesaving.[5] In severe cases of renal dysfunction, dialysis may be required.

    -- Although ribavirin has shown efficacy against hantavirus haemorrhagic fever with renal syndrome, it has not demonstrated effectiveness for HPS and is not licensed for either treatment or prophylaxis of hantavirus pulmonary syndrome.  

    -- At present, there is no specific antiviral treatment approved for HPS; a number of existing drugs have antiviral activity in laboratory studies but not yet demonstrated in human disease.

    -- Public health awareness efforts should focus on improving early detection, ensuring timely treatment, and reducing exposure risks. 

    -- Preventive measures should address occupational and ecotourism-related exposures, emphasize infection prevention and control measures, and include rodent control strategies. Most routine tourism activities carry little or no risk of exposure to rodents or their excreta.

    -- Risk communication and community engagement (RCCE) interventions should prioritize transparent, timely, and culturally appropriate communication to raise awareness of hantavirus transmission risks. 

    -- RCCE strategies should support coordinated, timely and aligned evidence-based information to ensure concerned people receive clear, consistent and actionable information, including explanations of the public health measures being implemented. 

    -- RCCE activities should explicitly address public concerns regarding transmissibility, severity, and international travel, and clarify what actions are and are not necessary for different population groups. 

    -- Operational measures should integrate RCCE activities throughout all phases of the event. The implementation of integrated environmental management strategies aimed at reducing rodent populations is also recommended.

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    -- At this time, WHO does not recommend any changes to routine activities for the general public. 

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    -- People who were on board the affected ship, or who have had close contact with a confirmed case, should follow the specific monitoring and public health advice outlined above. Guidance may be updated as further evidence becomes available.

    -- Based on the current information available on this event, WHO advises against the application of any travel or trade restrictions beyond the restriction of movement of identified high-risk contacts.

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{*} Standard precautions refer to a set of practices that are applied to the care of patients, regardless of the state of infection (suspicion or confirmation), in any place where health services are provided. These practices aim to protect both healthcare professionals and patients and include hand hygiene, use of personal protective equipment, respiratory hygiene and cough etiquette, safe handling of sharps materials, safe injection practices, use of sterile instruments and equipment and cleaning of hospital environments and the environment. Adapted from “Standard precautions for the prevention and control of infections: aide-memoire”- WHO, 2022.  Available at https://www.who.int/publications/i/item/WHO-UHL-IHS-IPC-2022.1  

Further information

1) World Health Organization. Management of contacts of Andes virus (ANDV) cases from the MV Hondius cruise ship. https://www.who.int/publications/m/item/management-of-contacts-of-andes-virus-(andv)-cases-fromthe-mv-hondius-cruise-ship

2) World Health Organization. WHO Technical note for the disembarkation and onward management of passengers and crew in the context of an Andes virus-associated cluster MV Hondius cruise ship. https://www.who.int/publications/m/item/who-technical-note-for-the-disembarkation-and-onward-management-of-passengers-and-crew-in-the-context-of-an-andes-virus-associated-cluster-mv-hondius-cruise-ship

3) World Health Organization. Hantavirus fact sheet. https://www.who.int/news-room/fact-sheets/detail/hantavirus 

4) World Health Organization.WHO’s response to hantavirus cases linked to a cruise ship. https://www.who.int/news/item/07-05-2026-who-s-response-to-hantavirus-cases-linked-to-a-cruise-ship

5) World Health Organization. Handbook for management of public health events on board ships https://www.who.int/publications/i/item/9789241549462

6) World Health Organization. Guide to Ship Sanitation, 3rd edition https://www.who.int/publications/i/item/9789241546690

7) Preliminary analysis of Orthohantavirus andesense virus sequences from a cruise-ship related cluster, May 2026. https://virological.org/t/preliminary-analysis-of-orthohantavirus-andesense-virus-sequences-from-a-cruise-ship-related-cluster-may-2026/1029

8) World Health Organization. Standard precautions for the prevention and control of infections: aide-memoire. https://www.who.int/publications/i/item/WHO-UHL-IHS-IPC-2022.1

9) World Health Organization. Transmission-based precautions for the prevention and control of infections: aide-memoire. https://www.who.int/publications/i/item/WHO-UHL-IHS-IPC-2022.2

10) World Health Organization. Hantavirus outbreak toolbox. https://www.who.int/emergencies/outbreak-toolkit/disease-outbreak-toolboxes/hantavirus-outbreak-toolbox

11) World Health Organization (8 May 2026). Disease Outbreak News. Hantavirus cluster linked to cruise ship travel, Multi-country. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON600

12) World Health Organization (4 May 2026). Disease Outbreak News. Hantavirus cluster linked to cruise ship travel- Multi-country. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON599

13) World Health Organization. A decision framework for effective, equitable and context-specific public health and social measures during public health emergencies: decision navigator: https://iris.who.int/server/api/core/bitstreams/ceaf4aa7-00c8-4681-9c35-965e231a3706/content

14) Pan American Health Organization / World Health Organization. PAHO supports the international response to hantavirus pulmonary syndrome cases linked to a cruise ship in the Atlantic. https://www.paho.org/en/news/7-5-2026-paho-supports-international-response-hantavirus-pulmonary-syndrome-cases-linked

15) Epidemiological Alert Hantavirus Pulmonary Syndrome (HPS). https://www.paho.org/en/documents/epidemiological-alert-hantavirus-pulmonary-syndrome-americas-region-19-december-2025   

16) Hantavirus in the Americas: Guidelines for diagnosis, treatment, prevention and control. Available at: https://iris.paho.org/handle/10665.2/40176

17) Hantavirus Prevention, CDC: https://www.cdc.gov/hantavirus/prevention/?CDC_AAref_Val=https://www.cdc.gov/hantavirus/hps/prevention.html

18) Martínez Valeria, Paola N, et al.. (2020). “Super-Spreaders” and Person-to-Person Transmission of Andes Virus in Argentina. New England Journal of Medicine. 383. 2230-2241. 10.1056/NEJMoa2009040.

19) US CDC. How to Clean Up After Rodents: https://www.cdc.gov/healthy-pets/rodent-control/clean-up.html

20) Hantavirus, Washington State Department of Heath, https://doh.wa.gov/sites/default/files/2025-08/420-056-Guideline-Hantavirus.pdf

21) Hantavirus Infection, MDS Manual, professional version: https://www.msdmanuals.com/professional/infectious-diseases/arboviruses-arenaviridae-and-filoviridae/hantavirus-infection

22) Handbook for management of public health events on board ships. https://www.who.int/publications/i/item/9789241549462

23) Hantavirus pulmonary syndrome, https://www.mayoclinic.org/diseases-conditions/hantavirus-pulmonary-syndrome/symptoms-causes/syc-20351838

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[1] Preliminary analysis of Orthohantavirus andesense virus sequences from a cruise-ship related cluster, May 2026. https://virological.org/t/preliminary-analysis-of-orthohantavirus-andesense-virus-sequences-from-a-cruise-ship-related-cluster-may-2026/1029

[2] Pan American Health Organization / World Health Organization (PAHO/WHO). Epidemiological Alert Hantavirus Pulmonary Syndrome (HPS). https://www.paho.org/en/documents/epidemiological-alert-hantavirus-pulmonary-syndrome-americas-region-19-december-2025

[3] Hantavirus infection - Annual Epidemiological Report for 2023. https://www.ecdc.europa.eu/en/publications-data/hantavirus-infection-annual-epidemiological-report-2023

[4] WHO Director-General's opening remarks at the media briefing on hantavirus – 12 May 2026. https://www.who.int/news-room/speeches/item/who-director-general-s-opening-remarks-at-the-media-briefing-on-hantavirus---12-may-2026

[5] Dietl CA, Wernly JA, Pett SB, et al. Extracorporeal membrane oxygenation support improves survival of patients with severe Hantavirus cardiopulmonary syndrome. The Journal of Thoracic and Cardiovascular Surgery. 2008;135(3):579-584. doi:10.1016/j.jtcvs.2007.11.020. 

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Citable reference: World Health Organization (13 May 2026). Disease Outbreak News. Hantavirus cluster linked to cruise ship travel, Multi-country. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON601

Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON601

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Technical note for disembarkation and onward #management of #passengers and crew in context of an #Andes virus-associated cluster MV Hondius cruise ship - Interim #guidance 8 May 2026 (WHO, edited)

 

Introduction

-- This technical note is intended for public health authorities, port health authorities, and partner agencies involved in the disembarkation, onward travel, monitoring, and follow-up of passengers and crew associated with the MV Hondius event.

Communication

-- Managed by: National health authorities / public health and medical evaluation team / risk communication specialists

-- Effective risk communication is essential to support the safe and orderly disembarkation and onward management of passengers and crew, and to maintain public trust during an evolving public health event. 

-- Member States should ensure that communication activities are coordinated, timely, and aligned with operational measures described in this technical note. 

-- Passengers and crew should receive clear, consistent and timely information before, during and after disembarkation, including explanations about public health measures, what to expect at each step, and next steps. 

-- Further considerations on risk communication are available in Annex 1.

1. Upon Arrival

Ship regulations

-- Managed by: Ship captain

• The required documentation should be provided to port health authorities, including the valid Ship Sanitation Certificate and the Ship Declaration of Health (or Maritime Declaration of Health).

• The ship should comply with the public health measures recommended by port health authorities, including for measures that need to be applied on board as well as during disembarkation, or medical evacuation.

• The ship captain should notify port health authorities of any person that meets the suspect case definition as assessed by physicians on board.

Communication to passengers and crew members

-- Managed by: captain / evaluation team / crew / communications officer

• Clearly communicate the steps that will be implemented.

• Inform that the disembarkation and onward travel of passengers and crew are being managed through coordinated and controlled public health measures, and that the risk to the general public remains very low.

• Communication should be reassuring yet vigilant, noting that people who have been exposed may still be at risk of developing symptoms and highlighting the importance of recognizing and reporting symptoms early.

2. Upon disembarkation

-- Managed by: national authorities

- Considering the attention attracted by this event, national authorities should ensure arrangements for security and media management in the port receiving the ship.

Management of passengers with symptoms prior to disembarkation

-- Managed by: medical team on board / national health authorities at the port of call

• Duly equipped ambulances should be pre-positioned at the port.

• If a suspected case is identified prior to the arrival of the ship, their medical evacuation to designated health facilities on-shore should be facilitated first, prior to disembarkation of passengers and crew.

• A designated trained team should be able to provide immediate care and ensure the safe and timely transfer to designated health facilities equipped to provide the appropriate level of safe and quality care.

• Any member of the medical team at the port of disembarkation, including ambulance crews, should apply standard and transmission-based precautions when attending cases.

    o Perform hand hygiene before putting on personal protective equipment (PPE).

    o Put on PPE items including eye protection, respirator (e.g. N95, FPP2), gown, and gloves before assessing, and transferring the case to a designated health facility on shore.

    o PPE should be removed once patient transfer has been completed, and hand hygiene performed after removal of PPE items. PPE should be managed as infectious waste.

• Ensure patients use a respiratory (e.g. N95, FPP2) during the transfer.

• Transport of patients should be carefully planned to ensure those sending the patient and receiving them are fully informed and prepared.

• See Annex 2 and 3 for further information.

Steps for disembarkation for passengers and crew members

-- Managed by: national health authorities at the port of call.

• Provide guidance to the crew on organizing the order of disembarkation (e.g. prioritizing passengers according to their location on the ship, followed by crew members, including instructions on how to wear a respirator).

• Staggering the disembarkation of passengers may be considered to ensure safe and efficient disembarkation. Individuals should disembark one by one from the ship.

• Respirators (N95, FPP2) should be provided prior to disembarkation to all passengers and crew members, under the assumption that it cannot be ruled out if contacts are symptomatic until they have been screened.

• All passengers and crew members disembarking should wear a well-fitted respirator{1} prior to disembarkation and until screening is undertaken.

• Individuals should ideally carry minimal hand luggage, with the remaining luggage handled separately by the ship’s company.

• Transport (ideally facilitated through boats or coach) should be available and ready to transport individuals to the onward location. Windows should be kept open for ventilation.

Screening area for passengers and crew members

-- Managed by: national health authorities at the port of call.

• National health authorities will define the best location to organize the screening of disembarking passengers and crew. It may be organized while passengers and crew are exiting the boat one by one or in a designated screening area on shore.

• Screening area(s) should be organized in a dedicated, pre-identified location in the port area, preferably outdoors but allowing for privacy, and with seats (distanced at least one meter apart), access to dedicated bathroom facilities, hand hygiene products and drinking water available in the waiting area.

• If indoors, the room should be well-ventilated (open windows), large enough to maintain distancing of at least one meter between people, have separate entrance and exits with one-way flow to maintain distancing and crowd control, and have provision for personal comfort i.e., toilets, seating (one meter apart), supply of individual water, and waste facilities.

• Toilet and rest facilities should be separate from those for reception and assessment staff.

• Administration and support staff should be allocated to ensure compliance with public health recommendations and are advised to wear medical masks, with access to hand hygiene facilities (soap and water or alcohol-based hand solutions).

• The screening area should ensure that at least one meter distance between the screener and the passenger/crew member is maintained. Temperature checks should be undertaken with non-touch thermometers.

• Respirators, masks and hand hygiene stations should be available in the screening area.

• Adequate environmental cleaning and disinfection of surfaces and shared equipment in the screening area should be performed between screenings.

• Equipped ambulances and their staff should be prepositioned prior to disembarkation, in case a medical evacuation is needed.

Screening and evaluation of passengers and crew members at disembarking

-- Managed by: national health authorities / evaluation team

Note: a team on the ship is currently assessing passengers and crew for exposure and health status. Coordination among this team and the evaluation team at disembarkation is strongly encouraged.

• In coordination with the ship, data on exposures should be examined to facilitate rapid exposure assessments.

• All passengers and crew should be provided with clear information including why measures are in place, what happens next (monitoring, travel, contact points), what symptoms to watch out for, and who to immediately contact 24/7 if any symptom develops.

• Investigation and medical teams should be mindful of the high-stress environment experienced by the passengers and crew and ensure empathy when conducting screening.

• All passengers and crew members are advised to wear a well-fitted respirator (e.g. FFP2, N95) while being assessed by port health authorities.

• During assessment, passengers and crew members will be checked for fever with non-touch thermometers, evaluated for their exposure and any symptoms they might have or have had.

• The above procedures shall be conducted by trained medical teams.

• During evaluation, any passenger or crew member with symptoms compatible with the suspected case definition (see Management of contacts of Andes virus (ANDV) cases from the MV Hondius cruise ship) should be managed as described in the next section.

• Health personnel conducting screening should apply standard IPC precautions, including:

    o Perform hand hygiene before and after the screening of contacts.

    o Use of gloves if touching travelers and when handling potentially contaminated materials.

    o Health personnel are advised to wear a medical mask and eye protection during screening of passengers and crew members at disembarking.

    o Medical masks should be disposed of if they become soiled or wet.

    o Adequate quantities of PPE items and hand hygiene material should be available in the evaluation area.

• Ideally, those disembarking should be pre-cleared by immigration authorities to avoid the need for contact with immigration staff. If they must pass through immigration, they should do so after screening, and immigration staff should wear a medical mask and have access to hand hygiene facilities (soap and water or alcohol-based hand solutions).

Management of passengers or crew members with symptoms identified at the time of screening

-- Managed by: national health authorities

• During evaluation, if a person presents symptoms compatible with ANDV infection (see case definition in Management of contacts of Andes virus (ANDV) cases from the MV Hondius cruise ship), the medical team should:

    o Practice hand hygiene and ensure adequate PPE as described above and in annex 3.

    o Isolate the patient in a designated area with a dedicated bathroom and dedicated linen/personal items while transfer for evacuation is organized.

    o Initiate the medical evacuation of the person to a designated health facility as indicated above.

    o PPE must be changed between patients, and hand hygiene should be performed before putting on PPE, and after removing PPE.

• When transferring, ensure the patient wears a respirator and the health worker wears PPE (eye protection, respirator (e.g. N95, FPP2), gown, gloves).

• Initial symptomatic treatment should be initiated for symptom control and if needed, any supportive care intervention, i.e. oxygen if hypoxemic. A monitoring plan should be put into place to ensure any clinical deterioration is noted in a timely fashion.

• See Annex 2 and 3 for further information.

Mental health and psychosocial support (MHPSS) for passengers and crew members

-- Managed by: MHPSS team, national health authorities.

• Mental health and psychosocial support should be considered for passengers and crew disembarking, as this situation may have generated significant stress in some.

• The availability of psychosocial support could help address anxiety or distress associated with the disembarkation process and perceived health risks.

Management of passenger and crew luggage and belongings

-- Managed by: conveyance operator / competent authorities

• Luggage will be handled after disembarkation by the conveyance operator, in collaboration with competent authorities.

• Passengers and crew members will be able to take their luggage back after screening is completed, in accordance with the protocols established by the competent authorities.

3. After disembarking

Onward travel of asymptomatic passengers and crew members

-- Managed by: national health authorities in country of repatriation

- For further guidance, see Management of contacts of Andes virus (ANDV) cases from the MV Hondius cruise ship.

- Asymptomatic passengers may travel following repatriation from the Canary Islands, provided that

- they have completed the active monitoring and in designated facility or home quarantine. Which includes:

• Public health authorities should conduct daily follow-up for 42 days after disembarkation, during which time the passenger should be advised to avoid contact with other persons through remaining in a designated facilities or at home, depending on national guidelines and capacities. 

• Follow-up may occur by telephone, messaging, telehealth, or in person.

• Passengers who are healthcare workers should refrain from returning to work for designated period.

• Passengers should avoid contact with other household members, and where possible and remain in a separate room.

• In case social interactions are unavoidable, passenger should wear a FFP2 or N95 respirator, practice physical distancing, and observe regular hand hygiene.

• All travel, nationally and internationally, should be discouraged for 42 days.

• Movement of the passenger out of the jurisdiction of public health authorities in charge of their follow-up may be allowed for life-threatening or humanitarian reasons, provided that arrangements are made with the public health authorities in the jurisdiction at destination, including internationally through IHR channels.

• During daily follow-up, any symptoms: temperature, fever, fatigue or malaise, muscle ache, headache, gastrointestinal symptoms, respiratory symptoms, should be promptly reported using a contact follow-up form.

• Any passengers developing symptoms compatible with hantavirus infection should be promptly isolated, clinically evaluated and tested.

• Passengers should receive:

    o Written information on symptoms to look out for.

    o Emergency contact numbers.

    o Instructions regarding healthcare seeking and testing.

Crew management

-- Managed by: cruise operator / competent authorities

• Medical care, including public health preventive measures, for crew members should be provided in accordance with the Maritime Labour Convention, 2006, as amended (MLC, 2006)

• Crew members should not resume duty on another ship until they complete the active monitoring and in designated facility or home quarantine (as above)

Management of deceased persons confirmed for ANDV infection on the ship

-- Managed: national authorities at port of call.

- Transmission of ANDV from deceased persons has not been documented, and viral load decreases before terminal illness; however, other respiratory pathogens (e.g., tuberculosis) have been transmitted from human remains. Thus, as exposure to bodily fluids and respiratory secretions may occur during handling of remains, standard IPC precautions should be applied when managing deceased suspected, probable, or confirmed cases.

• Personnel handling remains should apply standard IPC precautions and wear appropriate PPE, including gloves, gown, medical mask, and eye protection where exposure to bodily fluids or respiratory secretions is possible.

• Hand hygiene should be performed before and after PPE use and after contact with the body or contaminated materials.

• Unnecessary manipulation of the body and aerosol-generating procedures should be avoided.

• The body should be placed in a leak-proof body bag if needed and handled according to national procedures.

• Environmental cleaning and disinfection of potentially contaminated surfaces and equipment should be performed using appropriate disinfectants.

• International repatriation of remains may proceed according to national and international regulations.

Ship disinfection

-- Managed by conveyance operator and competent authorities

• The ship should be inspected for rodents, cleaned, disinfected and appropriate rodent control measures implemented, as appropriate, in accordance with the Integrated Management Plan of the Ship and WHO guidance, and as per advice of the competent authority.

• The ship shall cease to be regarded as affected when the competent authority is satisfied with the measures implemented, and there are no conditions on board that could constitute a public health risk.

• Staff involved in sanitary procedures on board the ship should wear adequate PPE (including eye protection, respirator, gown, and gloves).

Plans for updating

-- WHO continues to monitor the situation closely for any changes that may affect this interim guidance. 

-- Should any factors change, WHO will issue a further update. 

-- Otherwise, this interim guidance will expire one year after the date of publication.

References

1. World Health Organization. International Health Regulations (2005) – As amended in 2014, 2022 and 2024. https://apps.who.int/gb/bd/pdf_files/IHR_2014-2022-2024-en.pdf

2. World Health Organization. WHO Guideline on Contact Tracing; 2025. https://www.who.int/publications/i/item/9789240102965

3. World Health Organization. Handbook for Management of Public Health Events on Board Ships; 2016. https://www.who.int/publications/i/item/handbook-for-management-of-public-health-events-on-board-ships

4. World Health Organization. Vector Surveillance and Control at Ports, Airports, and Ground Crossings; 2016. https://www.who.int/publications/i/item/vector-surveillance-and-control-at-ports-airports-and-ground-crossings

5. World Health Organization. Guide to Ship Sanitation. 3rd edition; 2011. https://www.who.int/publications/i/item/9789241546690

6. World Health Organization. Handbook for inspection of ships and issuance of ship sanitation certificates; 2011. https://www.who.int/publications/i/item/handbook-for-inspection-of-ships-and-issuance-of-ship-sanitation-certificates

7. World Health Organization. Considerations for strengthening international information sharing for tracing and managing infectious disease cases and contact persons: Interim Guidance; 2026. https://www.who.int/southeastasia/internal-publications-detail/sewhe09022601

8. World Health Organization. World Health Organization. A decision framework for effective, equitable and context-specific public health and social measures during public health emergencies: decision navigator.

9. EU Healthy Sailing. Evidence-based guidelines for the specificities and needs of medical operations in expedition passenger ships. 2026

10. WHO and ICRC. Basic Emergency Care. Approach to the acutely ill and injured. 2018. https://www.who.int/publications/i/item/basic-emergency-care-approach-to-the-acutely-ill-and-injured

Annex 1. Risk communication

-- Effective risk communication is essential to support the safe, orderly, and dignified disembarkation and onward management of passengers and crew members, and to maintain public trust during an evolving public health event. 

-- Member States should ensure that communication activities are coordinated, timely, and aligned with operational measures described in this technical note.

• Ensure that passengers and crew receive clear, consistent and timely information before, during and after disembarkation, including explanations of public health measures, what to expect and next steps.

• Ensure communication materials are available in the relevant languages of passengers and crew and in accessible formats.

• Communicate clearly that the disembarkation and onward return of passengers and crew are being conducted through coordinated and controlled public health procedures, and that the risk to the wider public remains low.

• Communication should be reassuring yet vigilant, noting that people who have been exposed may still be at risk of developing symptoms and highlighting the importance of recognizing and reporting symptoms early.

• Acknowledge openly what is known and what remains uncertain, that investigations are ongoing and that recommendations may be updated as new epidemiological or laboratory evidence becomes available.

• Explain that changes in guidance reflect standard precautionary public health practice.

• Provide passengers and crew with written and verbal information on symptoms to monitor, duration, procedures if symptoms develop and contact details for public health authorities responsible for follow-up.

• Promote early reporting of symptoms and cooperation with monitoring arrangements and any other public health measure advised while traveling home.

• Ensure communication materials and briefings emphasize respect for the dignity, privacy and rights of passengers and crew and explicitly discourage stigma, discrimination, or blame.

• Ensure that communication at points of entry (ports, airports, transit hubs) is coordinated across agencies and consistent in messaging to avoid confusion or contradictory messages.

• Provide host communities, transit authorities, and destination countries with clear public information on the rationale for measures in place, what to expect, and what actions are not required.

• Establish clear channels for two-way communication, allowing passengers and crew to ask questions, raise concerns, and seek clarification throughout disembarkation and onward management.

• Monitor public perceptions, media coverage, and misinformation related to the event and adapt communication content and tone as needed, in coordination with WHO and relevant partners.

Annex 2. IPC for healthcare workers caring for suspected or confirmed cases

• Suspected, probable or confirmed cases must be isolated in single rooms (one room per case).

• In addition to standard precautions, implement transmission-based precautions when providing care to suspected or confirmed cases.

• Those providing care should wear personal protective equipment prior to entering the isolation room.

    o Perform hand hygiene before donning PPE.

    o PPE items include: eye protection, respirator (e.g. N95, FPP2), gown, gloves when providing direct patient care.

    o PPE should be removed and appropriately disposed of when exiting the isolation room, and hand hygiene must be performed after removal of PPE items.

• Ensure adequate indoor ventilation.

• Routine environmental cleaning and disinfection should be performed using regular disinfectants.

• Medical waste and used linen should be handled as per existing procedures.

• When transferring, ensure the patient wears a respirator and the healthcare worker wears PPE (eye protection, respirator (e.g. N95, FPP2), gown, gloves).

• Transport of patients should be carefully planned to ensure sending/receiving ends are fully informed and prepared.

Annex 3. Considerations on clinical management of suspected and confirmed patients

-- Medical management of a person with suspected, probable or confirmed hantavirus infection should be structured through standard protocols using appropriate PPE (see above), including:

• Severity-based triage of the condition using clinical and physiological measures (see WHO Basic Emergency Care).

• Systematic assessment, and rapid emergency action to address problems in Airway, Breathing, Circulation, Disability [ABCDE].

• Establishing a diagnosis is a priority (PCR and serology testing), but all patients should be managed according to the severity of disease. Outbreak case definitions are not a substitute for clinical judgment.

• High-quality and anticipatory supportive care should be provided.

    * Oxygen and availability of respiratory support should be prioritised.

    * Deterioration after the prodromal phase can be precipitous (over hours). Anticipatory actions should include careful monitoring and ensuring proximity to intensive care facilities for cardiovascular support, mechanical ventilation, and ideally extracorporeal membrane oxygenation.

    * Shock should be treated according to existing clinical guidelines for sepsis.

    * Ensure monitoring of vital signs and renal function (through clinical and biochemical assays). Investigation and monitoring of platelet count and proteinuria should be in place as these provide early insight into adverse prognosis, and imminent acute kidney injury respectively.

    * There are no proven antiviral treatments for hantavirus. Off-label use of favipiravir, remdesivir and other existing drugs have been used. Such use must be accompanied by detailed clinical data capture under monitored use. Mechanistically, remdesivir is less favourable compared with favipiravir due to its relatively reduced action against segmented viruses such as hantavirus).

• Direct evidence related to the use of corticosteroids in hantavirus infection for pulmonary or renal syndromes is limited. A single randomized controlled trial of patients with Andes virus hantaviral infection with cardiopulmonary syndrome in Chile did not demonstrate a benefit from high dose corticosteroid treatment but was underpowered to detect a moderate difference between arms.

• Routine antibiotic administration is not indicated for known hantavirus disease. However, for those presenting with symptoms of acute respiratory infection, bacterial infection must be considered. Suspicion of superadded bacterial infection is also an indication for antibiotic treatment based on clinical assessment.

Annex 4. Considerations on laboratory diagnosis

NOTE. Further information on laboratory diagnosis will be provided in a separate document and will cover additional aspects.

• Laboratory diagnosis of hantavirus infection relies on either molecular detection of viral RNA and serological detection of antibodies, with the choice depending on the interval between symptom onset and sample collection.

• By the time symptoms develop, viremia is often already at or near its peak, and both IgM and IgG antibodies may be detectable. IgM levels begin to decline over the following weeks and typically disappear within about three months, whereas IgG appears slightly later and may remain elevated for many years.

• For molecular detection, whole blood is recommended, while serum and blood clot can also be used. Serum is the preferred specimen for serology, although plasma from whole blood is also acceptable. Samples should be collected in sterile plastic tubes with screw caps.

Testing of suspected cases

• Suspected cases should be tested using an Andes virus–specific RT-PCR protocol, as outlined in reference laboratory procedures posted on the WHO EIS Platform and in the WHO Disease Outbreak News. In the absence of Andes virus-specific RT-PCR, a pan-hantavirus PCR can be used, and sequencing should be performed to confirm Andes virus.

• Molecular detection by RT-PCR, whether conventional or real-time, can confirm infection at any point during the acute phase, up to approximately ten days after symptom onset.

• If a sample has been collected more than 10 days after onset, a negative RT-PCR result in a properly collected and preserved sample, only rules out infection when serological testing is also negative, provided that enough time since last exposure has elapsed to allow development of anti-Andes virus specific antibodies.

• Positive cases without an epidemiological link to a confirmed or probable case should be systematically sequenced.

Testing of asymptomatic contacts for research purposes

• Routine testing of asymptomatic contacts is not mandatory for public health purposes.

• Regular (e.g. weekly) RT-PCR testing of asymptomatic contacts, on specimens such as blood, saliva, oral swabs and nasopharyngeal swabs, could be considered for research purposes to better understand virus shedding and transmission dynamics.

• However, testing should NOT be used to determine the end of the follow-up period, which remains fixed at 42 days after last exposure regardless of test results.

• When testing capacity is limited, symptomatic contacts must always be prioritised for diagnostic testing because they are more likely to be infected and require timely clinical evaluation.

• Serological testing at the beginning and end of the follow-up period may also be considered to ascertain serological status of contacts.

© World Health Organization 2026. Some rights reserved. This work is available under the CC BY-NC-SA 3.0 IGO license.

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{1} The recommendation for contacts to wear a well-fitted respirator (N95, FFP2) until screening is undertaken is a precautionary source control measure aimed at reducing the risk of onward transmission from individuals who might be symptomatic and pre-symptomatic.

Source: 

Link: https://www.who.int/publications/m/item/who-technical-note-for-the-disembarkation-and-onward-management-of-passengers-and-crew-in-the-context-of-an-andes-virus-associated-cluster-mv-hondius-cruise-ship

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Seasonal #influenza - #Global #situation (#WHO, Dec. 10 '25, excerpts)

 

10 December 2025

Situation at a glance

Seasonal influenza (‘the flu’) is an acute respiratory infection caused by influenza viruses that circulate globally and year-round. 

It can cause illness ranging from mild to severe, sometimes resulting in hospitalization or death. 

Seasonal influenza activity has increased globally in recent months, with an increased proportion of seasonal influenza A(H3N2) viruses being detected. 

This rise coincides with the onset of winter in the northern hemisphere and an increase in acute respiratory infections caused by influenza and other respiratory viruses typically observed at this time of year. 

Although global activity remains within expected seasonal ranges, early increases and higher activity than typical at this time of year have been observed in some regions. 

Seasonal influenza viruses, including A(H3N2) viruses, continually evolve over time. 

Since August 2025, there has been a rapid increase of A(H3N2) J.2.4.1 alias K subclade viruses detected from several countries based on available genetic sequence data. 

These subclade K viruses have several changes from related A(H3N2) viruses. 

Current epidemiological data do not indicate an increase in disease severity, although this subclade marks a notable evolution in influenza A(H3N2) viruses. 

Early estimates suggest that the influenza vaccine continues to provide protection against hospital attendance in both children and adults, even though its effectiveness against clinical disease during the current season remains uncertain. 

Vaccines remain essential, especially for people at high risk of influenza complications and their care givers. 

Even if there are some genetic differences between the circulating influenza viruses and the strains included in the vaccines, the seasonal influenza vaccine may still provide protection against drifted viruses and the other virus strains included in the vaccine. 

Vaccination is still expected to protect against severe illness and remains one of the most effective public health measures. 

WHO continues to monitor global influenza activity and influenza viruses, supports countries in surveillance capacity and updates guidance as needed.

Description of the situation

Globally, influenza activity has increased since October 2025 with influenza A viruses predominant among the viruses detected globally.

In many northern hemisphere countries, acute respiratory infection levels increase at this time of year. 

These increases are typically caused by seasonal epidemics of respiratory pathogens such as influenza, respiratory syncytial virus (RSV) and other common respiratory viruses. 

The exact timing of the onset, the duration, magnitude and the severity of each epidemic might vary by location, influenced by multiple factors such as type of circulating viruses (including influenza and other respiratory pathogens), relative population immunity and environmental conditions.

In the northern hemisphere, some countries have reported early starts to the influenza season. 

In other countries, influenza activity is starting to increase, but has not yet reached the epidemic threshold.

In the southern hemisphere, some countries have had unusually long seasons compared to previous years, with virus activity remaining higher than usual in recent months.

Global influenza surveillance and monitoring is conducted through the Global Influenza Surveillance and Response System (GISRS), a WHO-coordinated network of over 160 institutions in 131 Member States. 

GISRS is tasked with conducting year-round surveillance and monitoring of influenza viruses and serving as the global alert mechanism for the emergence of novel influenza viruses and other respiratory pathogens with pandemic potential.

In the northern hemisphere temperate and sub-tropical countries, areas and territories, influenza activity was generally low from June to August 2025. 

Activity gradually increased in September and continued to increase through November 2025. Influenza A viruses, especially A(H3N2) viruses, predominated during this period (...).

In the southern hemisphere temperate and sub-tropical countries, areas and territories, influenza activity generally decreased from June 2025 and remained low through August. 

However, a slight increase has been observed since September. 

Influenza A(H1N1)pdm09 viruses predominated in June and July; however, A(H3N2) viruses have predominated since September (...).

In tropical areas, there has been sustained influenza activity from June through November. 

Influenza A(H1N1)pdm09 viruses predominated through July. Since then, the proportion of influenza A(H3N2) viruses among reported detections has increased and has become predominant since the end of September (...).

(...)

Genetic characteristics of recent seasonal influenza viruses

Influenza A(H1N1)pdm09 and influenza B/Victoria lineage viruses continue to circulate in all regions albeit at low levels.

Influenza A(H3N2) viruses

Based on genetic sequence data available in GISAID, a mixture of A(H3N2) haemagglutinin (HA) clades and subclades are currently circulating globally; however, there has been a recent and rapid rise in a particular  subclade of A(H3N2), J.2.4.1 (alias subclade K Nextclade/Nextstrain nomenclature). 

A(H3N2) subclade K viruses have genetically drifted from related J.2.4 viruses and have several amino acid changes in their HA in comparison. 

Detections of subclade K viruses are increasing in many parts of the world, with the exception, to date, of South America. 

Subclade K viruses were particularly evident from August 2025 in Australia and New Zealand and have now been detected in more than 34 countries over the last 6 months.

(...)

Overview of seasonal influenza by WHO Region

African region

Influenza detections in the WHO African Region overall increased in October with influenza A(H3N2) predominant. 

The timing and predominant virus varied by zone. 

In the western part of the region, influenza detections increased in September and October with A(H3N2) predominant since October. 

All seasonal subtypes have been detected continuously in the middle and eastern parts of the region. 

Influenza activity peaked in May 2025 in South Africa with almost exclusively A(H3N2) detections; in recent weeks influenza activity has increased slightly but remained low.

Eastern Mediterranean Region

While influenza activity in the WHO Eastern Mediterranean Region overall increased in October with A(H3N2) viruses predominant, there were variations by zone. 

In countries in the northern part of the region, influenza detections increased in October with influenza A(H1N1)pdm09 predominant and lesser proportions of influenza A(H3N2) and B virus detections reported. 

In the Arabian Peninsula, influenza detections also increased in October but with influenza A(H3N2) viruses predominant.

European Region

As of 21 November 2025, reported rates of influenza-like illness (ILI) and/or acute respiratory infection (ARI) in primary care were at baseline levels for most countries and areas of the WHO European Region. 

However, detections were increasing and regionally pooled test percent positivity in primary care sentinel surveillance rose above 10% in weeks 45 and 46 (ending on 15 November), marking the start of the 2025/26 influenza season for the European Region. 

This was approximately four weeks earlier than the median, but not out of the ordinary, with epidemiological trends similar to those observed in the 2022/23 influenza season.

Influenza activity was variable between countries, with those in the west of the Region generally seeing earlier increases of influenza indicators compared to others. 

Influenza admissions, detections, and percent positivity in hospital surveillance were also increasing from inter-seasonal levels, with a higher proportion aged 65 years or older. 

A majority of influenza detections from sentinel and non-sentinel primary care and hospital surveillance systems were A(H3N2) viruses.

Region of the Americas

During the 2025 southern hemisphere season in the Americas, influenza transmission exceeded the seasonal threshold in mid-March, remaining mostly at low to moderate levels. 

Circulation was driven by influenza A(H1N1)pdm09, reaching a peak positivity of 19%. 

Activity then declined to low levels until the end of August, when an increase in circulation was observed, associated with influenza A(H3N2) in Brazil and Chile. 

As of beginning of November, Chile remains at moderate levels of influenza A(H3N2) transmission, without evidence of increased severity or rises in outpatient consultations. 

As of 4 November 2025, subclade K had not been detected in South America.

In the northern hemisphere countries of the Americas, during week 45 of 2025, seasonal influenza circulation remained low, with influenza A(H1N1)pdm09 predominating in the Caribbean and Central America. 

In North America, influenza activity—although still low—was increasing, mainly driven by influenza A virus detections. 

While most detections in Mexico were influenza A(H1N1)pdm09, a predominance of influenza A(H3N2) has been observed in the United States and Canada, with growing detections of the A(H3N2) subclade K.

South-East Asia Region

Influenza detections in the South-East Asia Region started increasing from June,  peaked in August and since then  have generally remained low with some exceptions. 

During the 2025 till November, the proportion of Influenza A among all influenza viruses tested positive was 66% Influenza A(H3N2) was the predominant sub-type (43%) in transmission followed by A(H1N1)pdm09 (~20%). 

In Thailand, influenza detections of predominantly A(H3N2) increased in October and November. 

Influenza A(H3N2) detections also increased since July in Bangladesh and October in Sri Lanka. 

While the region has seen an increase in Influenza A(H3N2), 22 sequences of   subclade K have   been reported in GISAID from Nepal (1), India (4) and Thailand (17) as of 30 November.

Western Pacific Region

Since the beginning of October 2025, influenza seasonal activity has increased in the Western Pacific Region. 

In some countries, including Japan and the Republic of Korea, the onset of the typical seasonal influenza activity period started earlier than in previous years. 

As of 9 November 2025, influenza positivity ranged from 8% to 56% in the northern hemisphere countries. 

In southern hemisphere countries, influenza activity shows mixed trends; positivity has declined in Australia, remains high in New Zealand and is rapidly increasing in Fiji. 

The elevated influenza activity in New Zealand and Fiji is unusual for this time of the year.

The predominant circulating influenza subtype is influenza A(H3N2), marking a shift from A(H1N1)pdm09, which predominated during the 2024-2025 northern hemisphere winter season. 

The increases in influenza have predominantly been driven by the expansion of A(H3N2) subclade K, which represents 89% of sequences submitted to GISAID from the Western Pacific Region (as of 21 November 2025). 

Epidemiology

Seasonal influenza (the flu) is an acute respiratory infection caused by influenza viruses that circulate globally and year-round. In temperate regions, seasonal influenza typically peaks during the winter months, whereas in tropical areas, influenza viruses can circulate year-round with seasonality and intensity that varies across countries.  

There are four types of influenza viruses, types A, B, C and D. Influenza A and B viruses circulate and cause seasonal epidemics of disease:

Influenza A viruses are further classified into subtypes according to the combinations of the proteins on the surface of the virus. Currently circulating in humans are subtype A(H1N1) and A(H3N2) influenza viruses. Influenza B viruses are not classified into subtypes but can be broken down into lineages. Influenza type B viruses belong to either B/Yamagata or B/Victoria lineage.

Influenza spreads easily between people when they cough or sneeze. Influenza disease can cause illness ranging from mild to severe, sometimes resulting in hospitalization or death. While most individuals recover within a week without need for medical care, influenza can lead to serious complication including death, especially among high-risk groups such as young children, the elderly, pregnant women and those with underlying conditions. Health and care workers are at high risk of acquiring influenza virus infection due to increased exposure to the patients, and of further spreading particularly to vulnerable individuals.

Public health response

WHO is enhancing national, regional, and global capacities for influenza preparedness and response, including:

-- continuous global monitoring of influenza viruses and disease activity;

-- issuing seasonal influenza vaccine composition recommendations for both hemispheres;

-- providing technical guidance to Member States on vaccine selection and campaign timing;

-- supporting countries in developing prevention and control strategies;

-- enhancing diagnostic capabilities and laboratory networks;

-- monitoring vaccine effectiveness and susceptibility to approved antivirals;

-- supporting disease surveillance and outbreak response activities;

-- promoting increased vaccine coverage among high-risk groups;

-- facilitating research and development of new therapeutics and countermeasures; and

-- enhancing risk communication for the onset of the influenza season.

WHO risk assessment

Seasonal influenza activity has increased globally in recent months, and influenza A(H3N2) viruses are predominant. 

This rise coincides with the onset of winter in the northern hemisphere. 

Epidemics and outbreaks of seasonal influenza and other circulating respiratory viruses can place significant pressure on healthcare systems.  

Although global activity remains within expected seasonal ranges, early increases and higher activity than typical at this time of year have been observed in some regions. 

Seasonal influenza could place significant pressure on healthcare systems even in non-temperate countries. 

Genetically drifted influenza A(H3N2) viruses, known as subclade K viruses, have been detected in many countries. 

While data on how well the vaccine works against clinical disease this season are still limited, vaccination is still expected to protect against severe illness and remains one of the most effective public health measures. 

WHO advice

Surveillance

Due to the constantly evolving nature of influenza viruses, WHO continues to stress the importance of year-round global surveillance to detect and monitor virological, epidemiological and clinical changes associated with emerging or circulating influenza viruses that may affect human health and timely virus sharing for risk assessment.  Countries are encouraged to remain vigilant to the threat of influenza viruses and review any unusual epidemiological patterns.

WHO advises Member States to maintain surveillance for respiratory pathogens through an integrated approach, considering country context, priorities, resources and capacities. WHO has published guidance on integrated respiratory virus surveillance. WHO has also updated guidance on assessing influenza epidemic and pandemic severity, including the impact on healthcare facilities.

Clinical management and prophylaxis

Clinical care for seasonal influenza focuses on identifying illness severity, assessing risk of progression, and linking to definitive care. Most cases are mild and self-limiting, but severe disease, marked by respiratory distress, sepsis, acute respiratory distress syndrome or multi-organ failure, requires urgent supportive care and often hospitalization. Clinical management of influenza involves high-quality supportive care—oxygen therapy, monitoring, hydration and respiratory support—and is foundational to improving outcomes, especially in severe cases.

Diagnostic testing should support rapid decision-making: nucleic acid amplification test (NAAT) is conditionally recommended for confirmation of suspected disease in severely unwell patients, while either NAAT or digital immunoassay may be used for non-severe cases, depending on context and resource availability. Testing should be performed early with the aim of identifying people in need of treatment and linking them to care, including antivirals where indicated.

Patients at high risk of progressing to severe disease are likely to benefit from antiviral to reduce their chance of admission to hospital. High-risk groups include adults ≥65 years, those with immunocompromising conditions, chronic cardiovascular, neurological or respiratory disease; malignancy, pregnancy and diabetes further elevate risk. Individuals ≥85 years or those with multiple risk factors are considered extremely high risk and might be considered for antiviral prophylaxis if exposed to influenza.

Infection prevention and control measures in health-care settings

Seasonal influenza is known to cause health care-associated infection outbreaks, in particular in long-term care facilities. WHO advises the use of syndromic screening at all entry points to health-care settings and as part of daily inpatient assessment to ensure that patients with suspected or confirmed infections that are transmissible in health-care settings, including influenza, are identified as soon as possible and that appropriate transmission-based precautions are implemented. WHO advises the use of droplet precautions when caring for patients with suspected or confirmed influenza. This includes appropriate patient placement (isolation) of suspected or confirmed cases, and the use of a medical mask by all health and care workers and visitors when caring for patients with suspected or confirmed influenza.

Appropriate risk assessment for additional personal protective equipment (e.g. eye protection, filtering facepiece respirators, gown, gloves) should be performed by health and care workers when caring for patients with influenza. 

Increased risk of influenza transmission may occur instances where care activities or patient symptoms are likely to generate splashes or sprays of blood, body fluids, secretions and excretions onto mucosa of eyes, nose or mouth; or if in close contact with a patient with respiratory symptoms (e.g. coughing/sneezing) and sprays of secretions may reach the mucosa of eyes, nose or mouth directly, or indirectly via contaminated hands. When performing an aerosol-generating procedure on patients with suspected or confirmed influenza, patient placement in an airborne infection isolation room as well as airborne and contact precautions with eye protection are advised.

Vaccination

Vaccination is the best way to prevent influenza disease. Safe and effective vaccines have been used for more than 60 years. Influenza viruses are constantly changing, so the composition of the seasonal influenza vaccine is regularly updated to contain viruses that are more related to those circulating. WHO, through the Global Influenza Programme and GISRS, in collaboration with partners, continuously monitors influenza viruses and activity globally and recommends seasonal influenza vaccine compositions in February and September for the following northern and southern hemisphere influenza seasons, respectively.

WHO recommends annual vaccination for high-risk groups, including health and care workers. People should ideally get vaccinated just before the influenza season begins for the most effective coverage, although getting vaccinated at any time during the influenza season can still help prevent flu infections. While the effectiveness of the vaccine may vary across seasons and risk groups, it reduces disease severity and lowers the chance of complications and death. Vaccination is especially important for people at high risk of influenza complications and their caregivers.

Genetic changes or drift can occur in the circulating influenza viruses before or during the influenza season, including during the time between vaccine strain selection and the influenza season. Even if there are some genetic differences between the circulating influenza viruses and the strains that are included in the vaccines, the seasonal influenza vaccine may still provide protection against drifted viruses. Current vaccines include three influenza viruses: influenza A(H1N1)pdm09, influenza A(H3N2) and influenza B/Victoria lineage viruses. Therefore, circulation of a drifted virus does not always result in seasonal influenza vaccines being less effective in offering protection against influenza associated illness.

As of now, it remains unclear how the vaccine will protect against clinical disease during this current season. However, early vaccine effectiveness estimates show the current vaccine is 70 to 75% effective at preventing hospital attendance in children aged 2 to 17 years and 30 to 40% effective in adults.[1],[2]

Public health and social measures in the community

The implementation of appropriate and proportionate public health and social measures (PHSM) is an essential component in the overall response to seasonal influenza epidemics. 

Measures such as performing hand hygiene, respiratory hygiene and cough etiquette as well as voluntary self-isolation and mask wearing of individuals who are symptomatic or have tested positive for influenza viruses can reduce transmission of influenza viruses.  

Countries should consider developing a plan to scale up additional PHSM in the event of high or extraordinarily high epidemics.  

Risk communication and community engagement

Member States should consider to update and strengthen their risk communication and community engagement (RCCE) strategy integrating respiratory viruses. Enhanced risk communication and community engagement approach support empowerment of individuals to make informed decisions, countering misinformation, and community-led protection strategies.

Clear, regular, evidence-based, culturally acceptable and context adapted RCCE approaches are essential for building and maintaining trust with the concerned and affected populations to ensure adoption of interventions, practices and behaviours. For RCCE efforts to be successful, it is vital that national policies for RCCE incorporate community engagement and feedback mechanisms that acknowledge and address contextual challenges faced by different population groups, particularly those made most vulnerable. The integration of RCCE approaches to promote vaccination against influenza is also recommended.

WHO does not recommend any restriction on travel to or trade with the countries named in this report, based on the information available on the current event.  

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Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON586

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