Highly Pathogenic Avian #Influenza A(#H5N1) in Wild #Birds and a #Human, British Columbia, #Canada, 2024

Abstract

We characterized highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b genotype D1.1 in wild birds and a human in British Columbia, Canada, during 2024. D1.1, the predominant genotype circulating in fall 2024, is a reassortment between Eurasian A3 lineage viruses, introduced to North America in 2022, and North American lineage viruses.

Source: US Centers for Disease Control and Prevention, https://wwwnc.cdc.gov/eid/article/31/6/24-1862_article

____

#Brazil, Ministry of #Health rules out case of {#H5N1} #birdflu virus infection in a #worker from Rio Grande do Sul

The Ministry of Health reports that a suspected case of Avian Influenza has been ruled out in a worker at a farm in the municipality of Montenegro (RS), where an outbreak of the disease was identified in birds. 

On the afternoon of Tuesday (20/05), Fiocruz, the reference laboratory for this type of analysis, confirmed that the test for the disease was negative. At this time, there are no other suspected or under investigation cases in Brazil.

The Ministry of Health, together with the State Health Department of Rio Grande do Sul, is monitoring all people who may have been exposed to the virus through direct contact with infected birds to monitor their health status, start treatment immediately at the first symptoms and preventative surveillance of possible contacts. 

There are no records of transmission of the disease from one person to another worldwide.

The risk of human infection is low and does not occur through the consumption of meat or eggs, but rather through direct contact with sick birds or contaminated environments. Therefore, the most effective preventive measure is to avoid contact with dead or sick birds.

The Ministry of Health is working with the Ministry of Agriculture and Livestock (Mapa) and the State Health Department of Rio Grande do Sul to provide all necessary support for actions related to the first case of bird flu on a commercial farm in the municipality of Montenegro (RS). 

To ensure a rapid response to possible outbreaks, the Ministry of Health launched, in December 2024, the National Contingency Plan for the Health Sector for Avian Influenza, which guides the ministry's actions, including integrated surveillance, laboratory diagnosis, assistance and health communication. 

In this sense, Brazil is working on different fronts to prepare for a possible risk of cases in humans. The Ministry of Health, through the SUS , has the capacity to perform laboratory tests, maintains a stock of the medicine to treat the different types of influenza (Oseltamivir) and, if necessary, has the technology to produce vaccines. 

Understand how the suspected case was ruled out

The investigation into the suspected case began on May 18, when the worker at the Montenegro (RS) farm, who was already being monitored by state surveillance and the Ministry of Health, showed the first symptoms. Treatment began immediately and the sample was sent to Fiocruz, in Rio de Janeiro.

The PCR test was initially performed, which identifies specific genetic material from the influenza virus – if positive, other tests are performed to identify the type of influenza, including avian flu. In the case in question, the initial test was negative for any type of influenza.

For those who work with wild animals, it is recommended to use Personal Protective Equipment (PPE) after identifying infected animals or those with symptoms suggestive of avian influenza, such as gloves, N95 mask or higher and eye protection, in addition to care such as hand hygiene, avoiding touching eyes, mouth and nose and changing clothes after contact with infected animals.

Ministry of Health 

Source: Ministry of Health, https://www.gov.br/saude/pt-br/assuntos/noticias/2025/maio/ministerio-da-saude-descarta-caso-de-gripe-aviaria-em-um-trabalhador-do-rio-grande-do-sul

____

#Pathogenicity and #transmissibility of bovine-derived HPAI #H5N1 B3.13 virus in #pigs

Abstract

Since the first emergence of highly pathogenic avian influenza (HPAI) H5N1 viruses in dairy cattle, the virus has continued to spread, reaching at least 17 states and at least 950 dairy herds in the United States. Subsequently, spillovers of the virus from dairy cattle to humans have been reported. Pigs are an important reservoir in influenza ecology because they serve as a mixing vessel in which novel reassortant viruses with pandemic potential can be generated. Here, we show that oro-respiratory infection of pigs resulted in productive replication of a bovine-derived HPAI H5N1 B3.13 virus. Infectious virus was mainly identified in the lower respiratory tract of principal infected pigs, and sero-conversion was observed in most of the principal pigs at later time points, suggesting limited replication of the bovine-derived HPAI H5N1 B3.13 virus in pigs. In one animal, we detected the emergence of a mutation in hemagglutinin (HA) previously associated with increased affinity for “mammalian-type” α2,6-linked sialic acid receptors, but this mutation did not reach majority consensus levels. Sentinel contact pigs remained sero-negative throughout the study, indicating lack of transmission. These results support that pigs are susceptible to a bovine-derived HPAI H5N1 B3.13 virus, but this virus did not replicate as robustly in pigs as mink-derived HPAI H5N1 and swine-adapted influenza viruses.

Source: Emerging Microbes and Infections, https://www.tandfonline.com/doi/full/10.1080/22221751.2025.2509742

____

#Bulgaria - High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) - Immediate notification

 

On the 19th of May, an official veterinary doctor was called to the farm due to suspected influenza, as there was an increase in mortality within the animals. On the same day, samples were taken and sent to the Bulgarian National Laboratory for Avian Influenza, where, on the 20th of May, it was confirmed that the farm was affected by a highly pathogenic avian influenza virus.

Source: WOAH, https://wahis.woah.org/#/in-review/6490

____

A protective and broadly binding #antibody class engages the #influenza virus #hemagglutinin head at its stem interface

ABSTRACT

Influenza infection and vaccination impart strain-specific immunity that protects against neither seasonal antigenic variants nor the next pandemic. However, antibodies directed to conserved sites can confer broad protection. Here, we identify and characterize a class of human antibodies that engage a previously undescribed, conserved epitope on the influenza hemagglutinin (HA) protein. Prototype antibody S8V1-157 binds at the normally occluded interface between the HA head and stem. Antibodies to this HA head–stem interface epitope are non-neutralizing in vitro but protect against lethal influenza infection in mice. These antibodies bind to most influenza A subtypes and seasonal human variants, and are present at low frequencies in the memory B cell populations of multiple human donors. Vaccines designed to elicit these antibodies might contribute to “universal” influenza immunity.

IMPORTANCE

Antibodies to the influenza virus hemagglutinin (HA) protein confer the strongest protection against infection. Human antibodies elicited by infection and/or vaccination fail to protect against antigenically novel animal, pandemic, or human seasonal viruses. Improved vaccines are needed. We identify a novel class of antibodies that bind most divergent HA subtypes and all seasonal human HA antigenic variants tested. These antibodies confer protection from lethal influenza challenge in animal models. The corresponding epitope on the HA head is occluded by its interaction with the stem and is inaccessible in the well-resolved prefusion state. The immunogenicity of this head–stem interface indicates that poorly understood conformations of HA presenting widely conserved surfaces are explored in biochemical, cell-based, and in vivo assays. Head–stem interface antibodies warrant further investigation as an avenue to improve influenza vaccines and therapeutics.

Source: mBio, https://journals.asm.org/doi/10.1128/mbio.00892-25

____

Characterization of emerging #H3N3 avian #influenza viruses in #poultry in #China

Abstract

Avian influenza viruses continue to challenge poultry and human health; therefore, careful surveillance and evaluation of emerging viruses are important for animal disease control and human influenza pandemic preparedness. In this study, we detected a series of H3N3 subtype avian influenza viruses in chickens, pigeons, and ducks during our routine surveillance and diagnosis between September 2022 and May 2023. We performed extensive analyses to fully understand the origins of these viruses and their risk to animals and humans. We found that the viruses were complex reassortants; the viruses from chickens and pigeons carry genes mainly derived from H3N8 viruses and H10N3 viruses, whereas the two duck viruses were reassortants of duck and wild bird viruses. The chicken and pigeon, but not duck, viruses replicated in multiple organs of chickens and were shed for up to 13 days, but none caused disease or death. Six of the viruses tested all bound to both avian- and human-type receptors. Seventeen viruses were tested in mice and most replicated efficiently but were not lethal. Six viruses were tested in guinea pigs, and four of them transmitted efficiently via respiratory droplets. Our study thus identified novel H3N3 avian influenza viruses and revealed their zoonotic potential, thereby emphasizing the importance of careful monitoring and control of H3 viruses in animals.

Source: Emerging Microbes and Infections, https://www.tandfonline.com/doi/full/10.1080/22221751.2025.2509748#

____

Investigating Factors Driving Shifts in Subtype #Dominance within #H5Nx Clade 2.3.4.4b High-Pathogenicity Avian #Influenza viruses

Abstract

H5Nx clade 2.3.4.4b high-pathogenicity avian influenza viruses (HPAIVs) have decimated wild bird and poultry populations globally since the autumn of 2020. In the United Kingdom (UK) and in continental Europe, the H5N8 subtype predominated during the first epizootic wave of 2020/21, with few detections of H5N1. However, during the second (2021/22) and third (2022/23) epizootic waves, H5N1 was the dominant subtype. The rapid shift in dominance from H5N8 to H5N1 was likely driven by a combination of virological, immunological, and/or host-related factors. In this study, we compared viral fitness and immunological responses in ducks, a key reservoir species, using dominant genotypes of H5N1 (genotype AB) and H5N8 (genotype A) from the second wave. While viral shedding dynamics were similar for both viruses, H5N8 was more pathogenic. Antigenic analysis of post-infection duck sera revealed that the haemagglutinin (HA) protein was antigenically similar across clade 2.3.4.4b H5 HPAIVs, but neuraminidase (NA) proteins displayed different patterns of cross-reactivity. We also modelled a scenario where ducks were pre-exposed to H5N1 (genotype C) or H5N8 (genotype A) from the first wave and subsequently challenged with either homologous or heterologous subtypes from the second wave (genotype AB or A). Despite the absence of seroconversion, pre-exposure to different subtypes resulted in varying clinical outcomes following challenge. These findings indicate that both viral and immunological factors likely played significant roles in the emergence and spread of H5Nx HPAIVs in wild bird populations.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.04.23.650244v2

____

Long-Term Clinical #Outcomes of #Adults Hospitalized for #COVID19 #Pneumonia

Abstract

We conducted a multicenter, observational, 12-month follow-up study to identify the extended health burden of severe COVID-19 pneumonia by characterizing long-term sequelae of acute infection in participants previously enrolled in clinical trials for severe COVID-19 pneumonia requiring hospitalization. Overall, 134 (77.5%) of 173 participants completed the study. At 12 months, 51 (29.5%) participants reported cough, 60 (34.7%) reported dyspnea, 56 (32.4%) had residual lung texture abnormalities on high-resolution computed tomography scans, 26 (15.0%) had impaired forced vital capacity, 52 (30.1%) had cognitive impairment, and 77 (44.5%) reported fatigue. Disease severity during acute infection and age were associated with persistent lung abnormalities; history of hypertension was associated with higher prevalence of fatigue and more frequent dyspnea and cough; and age and obesity were associated with long-term cognitive impairment. Our findings underscore the long-term health burden of severe COVID-19 pneumonia, reinforcing the importance of regular monitoring in older persons and those with underlying illnesses.

Source: US Centers for Disease Control and Prevention, https://wwwnc.cdc.gov/eid/article/31/6/24-1097_article

____

Progressive #Adaptation of Subtype #H6N1 Avian #Influenza Virus in #Taiwan Enhances #Mammalian #Infectivity, Pathogenicity, and #Transmissibility

Abstract

The interspecies transmission of avian influenza viruses remains a significant public health concern. H6 viruses have gained attention following the first human infection by a chicken-origin H6N1 virus (A/Taiwan/02/2013, Hu/13), highlighting their zoonotic potential. To understand the evolutionary trajectory and mammalian adaptation of this Taiwan lineage, we compared two avian isolates (A/Chicken/Taiwan/CF19/2009, Ck/09; A/Chicken/Taiwan/2267/2012, Ck/12) and Hu/13 in vitro and in vivo. Hu/13 exhibited enhanced replication in MDCK cells, producing larger plaques and higher viral titers than Ck/09 and Ck/12. In BALB/c mice, Hu/13 demonstrated the highest pathogenicity and mortality, followed by Ck/12, while Ck/09 induced minimal morbidity. Hu/13 and Ck/12 replicated efficiently in respiratory tissues, eliciting robust cytokine responses and severe pulmonary lesions. In ferrets, Hu/13 showed relatively efficient transmission, infecting all direct physical-contact and two out of three airborne-contact ferrets, whereas Ck/09 failed to transmit. Histopathology confirmed escalating lung pathology from Ck/09 to Ck/12 and Hu/13. Whole-genome sequencing identified adaptive mutations in Hu/13 during ferret replication, though no canonical mammalian-adaptive changes (e.g., PB2-E627K or HA-Q226L) were detected. These findings demonstrate progressive mammalian adaptation, replication efficiency, and transmissibility within the Taiwan H6N1 lineage. Enhanced surveillance is crucial to monitor mammalian-adaptive mutations, informing pandemic preparedness and public health strategies.

Source: Viruses, https://www.mdpi.com/1999-4915/17/5/733

____

#Phylogenetic Analysis and Spread of HPAI #H5N1 in Middle Eastern Countries Based on #Hemagglutinin and #Neuraminidase Gene Sequences

Abstract

Highly pathogenic avian influenza (HPAI) A/H5N1 viruses threaten animal and human health worldwide. The first documented cases in the Middle East were reported in 2005; however, despite extensive phylogenetic studies, there is limited information on the transmission dynamics of the virus within this region. We analyzed HA and NA gene sequences from various hosts to address this gap and to understand the virus’s spread and evolution in the Middle East. We hypothesized that H5N1 transmission exhibits host-specific or geographically influenced clade structures in this region. This study traced transmission pathways of HPAI A/H5N1 through a phylogenetic and amino acid sequence analysis of HA and NA gene segments from isolates across different hosts in Middle Eastern countries, using the MUSCLE algorithm for alignments and MEGA11 software for phylogenetic analysis. Sequences were selected from NCBI’s virus database based on geographic and host diversity, including those from birds, humans, and other mammals, and were collected at different time points, predominantly after the early 2000s. An amino acid phylogenetic tree was also constructed to examine the conservation of key HA and NA protein residues, identifying distinct clades linked to specific countries and host species, suggesting a possible interspecies transmission and cross-border spread distinct between Egypt and neighboring countries. These findings underscore the role of migratory birds in regional transmission and point to the need for more targeted surveillance and biosecurity efforts, offering more genomic insights into the spread of HPAI A/H5N1 and contributing valuable information for future prevention strategies.

Source: Viruses, https://www.mdpi.com/1999-4915/17/5/734

____

Avian #Influenza Virus #Infections in #Felines: A Systematic Review of Two Decades of Literature

Abstract

As an avian influenza virus (AIV) panzootic is underway, the threat of a human pandemic is emerging. Infections among mammalian species in frequent contact with humans should be closely monitored. One mammalian family, the Felidae, is of particular concern. Domestic cats are susceptible to AIV infection and provide a potential pathway for zoonotic spillover to humans. Here, we provide a systematic review of the scientific literature to describe the epidemiology and global distribution of AIV infections in felines reported from 2004 to 2024. We identified 607 AIV infections in felines, including 302 associated deaths, comprising 18 countries and 12 felid species. We observed a drastic flux in the number of AIV infections among domestic cats in 2023 and 2024, commensurate with the emergence of H5N1 clade 2.3.4.4b. We estimate that this phenomenon is underreported in the scientific literature and argue that increased surveillance among domestic cats is urgently needed.

Source: Open Forum Infectious Diseases, https://academic.oup.com/ofid/article/12/5/ofaf261/8123920

____

Endemic #coronavirus #infection is associated with #SARS-CoV-2 Fc receptor-binding #antibodies

ABSTRACT

Recent documented infection with an endemic coronavirus (eCoV) is associated with less severe coronavirus disease 2019 (COVID-19), yet the immune mechanism behind this protection has not been fully explored. We measured both antibody and T-cell responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in SARS-CoV-2-naïve individuals, classified into two groups: those with or without presumed recent eCoV infections. There was no difference in neutralizing antibodies and T-cell responses against SARS-CoV-2 antigens between the two groups. SARS-CoV-2-naïve individuals with recent presumed eCoV infection, however, had higher and significantly correlated levels of Fc receptor (FcR)-binding antibodies against eCoV spikes (S) and SARS-CoV-2 S2. Recent eCoV infection boosts cross-reactive antibodies that can mediate Fc effector functions, and this may play a role in the observed heterotypic immune protection against severe COVID-19.

IMPORTANCE

With the recent emergence of SARS-CoV-2 and other pathogenic coronaviruses, it is important to understand how the immune system may protect against disease from future coronavirus outbreaks. We investigated the adaptive immune responses elicited from a “common cold” eCoV and measured the cross-reactivity against SARS-CoV-2 in individuals classified as having or not having a recent eCoV infection. Although both groups had similar cross-reactive T-cell and neutralizing antibody responses, individuals with a recent eCoV infection had higher antibody levels capable of Fc receptor binding. Antibodies with enhanced Fc receptor binding could mediate the killing of virally infected cells through mechanisms such as antibody-dependent cellular cytotoxicity, which may reduce the severity of COVID-19. Antibodies capable of mediating Fc effector functions may be critical for therapies and vaccines against future pathogenic coronavirus outbreaks.

Source: Journal of Virology, https://journals.asm.org/doi/full/10.1128/jvi.00550-25?af=R

____

World #Health #Assembly adopts historic #Pandemic #Agreement to make the world more equitable and safer from future pandemics (#WHO)

Agreement’s adoption follows three years of intensive negotiation launched due to gaps and inequities identified in national and global COVID-19 response.

Agreement boosts global collaboration to ensure stronger, more equitable response to future pandemics.

Next steps include negotiations on Pathogen Access and Benefits Sharing system.

Member States of the World Health Organization (WHO) today formally adopted by consensus the world's first Pandemic Agreement. The landmark decision by the 78th World Health Assembly culminates more than three years of intensive negotiations launched by governments in response to the devastating impacts of the COVID-19 pandemic, and driven by the goal of making the world safer from – and more equitable in response to – future pandemics.

“The world is safer today thanks to the leadership, collaboration and commitment of our Member States to adopt the historic WHO Pandemic Agreement,” said Dr Tedros Adhanom Ghebreyesus, WHO Director-General. 

“The Agreement is a victory for public health, science and multilateral action. It will ensure we, collectively, can better protect the world from future pandemic threats. It is also a recognition by the international community that our citizens, societies and economies must not be left vulnerable to again suffer losses like those endured during COVID-19.”  

Governments adopted the WHO Pandemic Agreement today in a plenary session of the World Health Assembly, WHO’s peak decision-making body. The adoption followed yesterday’s approval of the Agreement by vote (124 in favour, 0 objections, 11 abstentions) in Committee by Member State delegations.

“Starting during the height of the COVID-19 pandemic, governments from all corners of the world acted with great purpose, dedication and urgency, and in doing so exercising their national sovereignty, to negotiate the historic WHO Pandemic Agreement that has been adopted today,” said Dr Teodoro Herbosa, Secretary of the Philippines Department of Health, and President of this year’s World Health Assembly, who presided over the Agreement’s adoption. 

“Now that the Agreement has been brought to life, we must all act with the same urgency to implement its critical elements, including systems to ensure equitable access to life-saving pandemic-related health products. As COVID was a once-in-a-lifetime emergency, the WHO Pandemic Agreement offers a once-in-a-lifetime opportunity to build on lessons learned from that crisis and ensure people worldwide are better protected if a future pandemic emerges.”

The WHO Pandemic Agreement sets out the principles, approaches and tools for better international coordination across a range of areas, in order to strengthen the global health architecture for pandemic prevention, preparedness and response. This includes through the equitable and timely access to vaccines, therapeutics and diagnostics.

Regarding national sovereignty, the Agreement states that: 

“Nothing in the WHO Pandemic Agreement shall be interpreted as providing the Secretariat of the World Health Organization, including the Director-General of the World Health Organization, any authority to direct, order, alter or otherwise prescribe the national and/or domestic law, as appropriate, or policies of any Party, or to mandate or otherwise impose any requirements that Parties take specific actions, such as ban or accept travellers, impose vaccination mandates or therapeutic or diagnostic measures or implement lockdowns.”

Notes for editors

The resolution on the WHO Pandemic Agreement adopted by the World Health Assembly sets out steps to prepare for the accord’s implementation. It includes launching a process to draft and negotiate a Pathogen Access and Benefit Sharing system (PABS) through an Intergovernmental Working Group (IGWG). The result of this process will be considered at next year’s World Health Assembly.

Once the Assembly adopts the PABS annex, the WHO Pandemic Agreement will then be open for signature and consideration of ratification, including by national legislative bodies. 

After 60 ratifications, the Agreement will enter into force.

In addition, Member States also directed the IGWG to initiate steps to enable setting up of the Coordinating Financial Mechanism for pandemic prevention, preparedness and response, and the Global Supply Chain and Logistics Network (GSCL) to “enhance, facilitate, and work to remove barriers and ensure equitable, timely, rapid, safe, and affordable access to pandemic-related health products for countries in need during public health emergencies of international concern, including pandemic emergencies, and for prevention of such emergencies.”

According to the Agreement, pharmaceutical manufacturers participating in the PABS system will play a key role in equitable and timely access to pandemic-related health products by making available to WHO “rapid access targeting 20% of their real time production of safe, quality and effective vaccines, therapeutics, and diagnostics for the pathogen causing the pandemic emergency.”  The distribution of these products to countries will be carried out on the basis of public health risk and need, with particular attention to the needs of developing countries.

The WHO Pandemic Agreement is the second international legal agreement negotiated under Article 19 of the WHO Constitution, the first being the WHO Framework Convention on Tobacco Control, which was adopted in 2003 and entered into force in 2005.

Source: World Health Organization, https://www.who.int/news/item/20-05-2025-world-health-assembly-adopts-historic-pandemic-agreement-to-make-the-world-more-equitable-and-safer-from-future-pandemics

____

Circulating vaccine-derived #poliovirus type 2 (#cVDPV2) - #Papua New Guinea (#WHO D.O.N., May 20 '25)

{Summary}

Situation at a glance

On 9 May 2025, the International Health Regulations (IHR) National Focal Point (NFP) for Papua New Guinea (PNG) notified WHO of the detection of circulating vaccine-derived poliovirus type 2 (cVDPV2) from stool specimens of two healthy children from Morobe province, Papua New Guinea (PNG). 

The detection of wild poliovirus (WPV) or vaccine-derived poliovirus (VDPV), including from samples taken from healthy children, is considered a serious public health event. 

Given the country's suboptimal routine immunization coverage, especially at the subnational level, the risk of potential spread locally is considered high. 

WHO advises all countries—especially those with frequent travel and connections to polio-affected areas—should strengthen acute flaccid paralysis (AFP) and environmental surveillance while maintaining high level of immunization coverage to quickly detect and respond to virus importation and prevent further spread by closing immunity gaps.

(...)

Source: World Health Organization, https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON571

____

Temperature-dependent #modulation of aberrant #influenza A virus #RNA #synthesis affects innate immune signaling

Abstract

Fever during influenza A virus (IAV) infection is triggered by the innate immune response. Various factors contribute to this response, including IAV mini viral RNAs (mvRNA), which trigger RIG-I signaling when their replication and transcription are dysregulated by template loops (t-loop). It is presently not well understood whether the fever response to IAV infection impacts subsequent viral replication and innate immune activation. Here we show that IAV infection at temperatures that simulate fever leads to increased mvRNA synthesis and antiviral signaling. Mathematical modeling and experimental analyses reveal that differential IAV nucleoprotein and RNA polymerase production underlies the increased mvRNA level. Moreover, at the higher infection temperature mvRNAs with dysregulating t-loops contribute most to the innate immune activation. We propose that fever during IAV infection can establish a positive feedback loop in which elevated aberrant RNA synthesis and innate immune activation may contribute to the dysregulation of cytokine production.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.05.19.654939v1

____

#Czech Republic - High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) - Immediate notification

 

Increased mortality of poultry, clinical signs, commercial holding of pheasants, hens, ducks, geese, peacocks.

Source: WOAH, https://wahis.woah.org/#/in-review/6486

____

Pharmacodynamic Effect of Different Dosage Regimes of #Oseltamivir in Severe #Influenza Patients Requiring Mechanical #Ventilation: A Multicentre Randomised Controlled Trial

ABSTRACT

Background and Objectives

This randomised controlled trial evaluated whether higher doses of oseltamivir would improve virological and clinical outcomes in severe influenza patients requiring invasive mechanical ventilation.

Methods

Forty intubated adult patients with severe influenza A or B from four intensive care units in Hong Kong were enrolled and randomised to receive either a double dose (300 mg/day) or a triple dose (450 mg/day) of oseltamivir for 10 days. Baseline data were collected, and outcomes were assessed daily using SOFA and Murray scores. Viral RNA was quantified from nasopharyngeal and tracheal aspirates. The primary outcome was the viral clearance rate after 5 days of treatment; secondary outcomes included 28-day and hospital mortality rates, changes in viral load, and serial SOFA and Murray scores.

Results

Viral clearance rates after 5 days of treatment were low and similar between the double (3/20, 15%) and triple-dose groups (2/20, 10%). No significant differences were observed in 28-day mortality, hospital mortality, ICU length of stay or duration of mechanical ventilation between the double and triple-dose groups. However, patients receiving triple doses exhibited a faster decline in influenza A viral load but had a longer hospital length of stay.

Conclusions

Triple doses of oseltamivir did not significantly improve virological or clinical outcomes compared with double doses in severe influenza.

Source: Influenza and Other Respiratory Viruses, https://onlinelibrary.wiley.com/doi/10.1111/irv.70109

____

#Brazil - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

 The Official Veterinary Services (OVS) received a notification of acute mortality and neurological signs in swans in a zoo. Laboratory analysis identified H5N1 virus clade 2.3.4.4b. OVS is conducting an epidemiological investigation of the event.

Source: WOAH, https://wahis.woah.org/#/in-review/6485

____

#Korea (Rep. of) - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

 A wild leopard cat in Gwangju Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6461

____

Modeling Effects of Routine #Screening for Accidental #Lab-Acquired #Infections on #Risk of Potential #Pandemic Pathogen #Escape from High-Biosafety Research Facilities

Abstract

Accidental lab–acquired infections (LAIs) risk releasing potential pandemic pathogens (PPPs) from BSL–3/4 facilities. We constructed a stochastic network infectious disease model to simulate how the probability of an outbreak of a pathogen resembling wild–type SARS–COV–2, following an initial LAI would be influenced by test–and–isolate interventions over a 100–day horizon. We varied test frequency (0–7 tests/week), peak sensitivity (50–100%), and isolation delay (0–3 days). For each of 192 parameter combinations, we conducted 1,000 simulations and used logistic regression to quantify how each parameter influenced the likelihood of an outbreak of 50 or more infections. Results indicated that even relatively infrequent routine testing significantly reduced the risk of outbreaks under diverse plausible scenarios, with greater reductions achieved at higher test frequencies. Once-weekly testing reduced outbreak risk by 52% under optimistic assumptions (80% sensitivity, 1–day delay) and by 29% under pessimistic assumptions (50% sensitivity, 2–day delay). Testing two and five times weekly yielded risk reductions of up to 62% and 71%, respectively, under optimistic assumptions, and 43% and 55%, respectively, under pessimistic assumptions. Logistic regression showed each additional weekly test decreased outbreak odds by 20%, each 10–point increase in test sensitivity reduced odds by 10%, and each additional isolation delay day increased odds by 15.5%. Interaction analyses revealed that longer isolation delays attenuated the protective effects of higher testing frequency and sensitivity. Routine lab worker screening with prompt isolation substantially mitigates PPP escape risks. High–frequency testing has the greatest impact, and policymakers should consider implementing regular screening protocols.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2025.05.16.25327796v1

____