High rates of #SARS-CoV-2 #reinfection in residents of long term care facilities despite robust #spike-specific #immunity following serial #vaccination

 

Abstract

Older adult residents of long-term care facilities (LTCFs) suffered high rates of mortality during the initial stages of the COVID-19 pandemic but their clinical risk has decreased markedly following vaccination. Here we determined humoral and cellular immunity following delivery of a 5th vaccine dose, an mRNA spike B1:BA.1 bivalent vaccine, to care home residents. The delivery of a 5th vaccine elicited a plateau of spike-specific immunity that remained broadly stable over 100 days in almost all people. Despite this, 15% of residents had a primary infection and 30% became reinfected during 6-months of follow up. These findings reveal that serial vaccine delivery can establish robust systemic spike-specific immune responses in frail older people but that this does not reliably prevent SARS-CoV-2 reinfection. As such, additional approaches should be considered to reduce reinfection risk in this vulnerable population group.

Source: 

Link: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0354079

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History of Mass Transportation: The DRB Class 03 Steam Locomotive of Poland Railways

 

{Click on Image to Enlarge}

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By The original uploader was Wassen at German Wikipedia.(Original text: wassen) - Self-photographed, CC BY-SA 2.0 de, https://commons.wikimedia.org/w/index.php?curid=3737550

Source: 

Link: https://en.wikipedia.org/wiki/List_of_rolling_stock_used_in_Poland#/media/File:Pm_3-5_als_Pm_3-3_Warszawa_06.04.05.jpg

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#Ebola disease caused by #Bundibugyo virus - #DRC (WHO D.O.N., August 15 '26): 4,665 cases and 2,184 deaths so far

 

Situation at a glance

    The Bundibugyo virus disease (BVD) outbreak in the Democratic Republic of the Congo is in a phase of intense transmission. 

    It is the largest Ebola outbreak ever reported in the country and expanding faster than any previous Ebola outbreak. 

    The epidemic is increasingly characterized by sustained transmission within interconnected geographic clusters. 

    Initially confined to the Mongbwalu health zone in Ituri Province, the outbreak has now expanded to 54 health zones across six provinces (Ituri, North Kivu, South Kivu, Haut-Uélé, Tshopo, and Bas-Uélé). 

    The most recently affected Bas-Uélé province recorded one confirmed case in Buta health zone with travel history to Haut-Uélé and onset of symptoms on 4 August. 

    As of 12 August 2026, a total of 4665 confirmed cases, including 2184 deaths, have been reported, corresponding to a crude case fatality ratio (CFR) of 46.8%. 

    The ongoing rise in cases, broader geographic spread, and continued high mortality demonstrate the rapidly changing scope of this public health emergency of international concern. 

    During the most recent reporting week (epidemiological week 32, 3 to 9 August 2026), the highest weekly number of reported cases (579) and deaths (304) were recorded, highlighting the exceptional pace of transmission. 

    The ongoing humanitarian crisis, compounded by insecurity, population displacement and mobility, and cross-border movements, continues to pose significant challenges to response efforts and increase the risk of further geographical spread. 

    National authorities in the Democratic Republic of the Congo, continue to implement extensive response measures in collaboration with WHO and partners. 

    However, a substantial scaling up of response activities is underway to get ahead of the outbreak. 

    Following their missions to the Democratic Republic of the Congo, WHO’s Director-General and Regional Director for Africa, and the Director General of Africa CDC, highlighted surveillance activities and closer work with communities as priority areas. 

    Expanding the number of treatment centers, across more areas, is underway, along with training for the health and care workers to staff them. 

    France has reported no secondary transmission following an imported case detected on 24 June 2026. 

    As of 14 August, 41 days had passed since the patient’s discharge on 4 July, with no additional confirmed cases reported. 

    In Uganda the most recent imported case was discharged from a treatment centre on 16 July, and the 42-day enhanced monitoring period will cease on 27 August. 

    Uganda remains at risk of BVD re-introduction due to ongoing transmission in neighbouring Democratic Republic of the Congo and is undertaking heightened surveillance activities given continued population movement and the risk of cross-border transmission. 

    A regional preparedness and prioritization framework continues to guide readiness and response activities across the African Region.

Description of the situation

    Since the previous Disease Outbreak News was published on 1 August 2026, additional confirmed cases and deaths of BVD have been only reported in the Democratic Republic of the Congo.  

    Cumulatively as of 12 August 2026, 4686 confirmed cases have been reported: 4665 in the Democratic Republic of the Congo (including two cases diagnosed in the Democratic Republic of the Congo and subsequently treated in Germany), 20 in Uganda and one in France. 

    A total of 2186 deaths have been reported, including two in Uganda. 

    As of 12 August, at least 986 patients have recovered including 965 in the Democratic Republic of the Congo, 18 from Uganda have recovered, two in Germany and one from France.  

    As reported in the Disease Outbreak News published on 1 August 2026, with more confirmed cases than the 2018-2020 outbreak, which reported 3,317 cases, this outbreak now represents the largest Ebola disease outbreak ever documented in the country. 

(...)

Democratic Republic of the Congo  

    Since 1 August 2026 when the last Disease Outbreak News was published, an additional 1060 confirmed cases, including 597 confirmed deaths, have been reported in the Democratic Republic of the Congo. 

    The increase is in part due to strengthened surveillance activities, enhanced laboratory testing, and diagnostic capacity. However, most of the increase reflects the expansion of the outbreak.  

    As of 12 August 2026, a total of 4665 confirmed cases, including 2184 deaths (CFR 46.8%), have been reported in the Democratic Republic of the Congo. To date, 965 patients have recovered. 

    Cases have been reported from 54 health zones (HZ) across six provinces: Ituri (28/36 HZ), North Kivu (12/34 HZ), South Kivu (1/34 HZ), Haut-Uélé (6/13 HZ), Tshopo (6/23 HZ), and Bas- Uélé (1/11 HZ). The most recently affected province, Bas-Uélé, reported one confirmed case in Buta Health Zone. The case had a travel history to Haut-Uélé, with symptom onset on 4 August. 

    As of 12 August, of the 54 affected health zones, 100 new confirmed cases were reported in the last 24 hours from 22 health zones in all affected provinces except for Sud-Kivu. 

    The highest number of new cases in the last 24 hours (67) was reported from Ituri province followed by Nord-Kivu (25). Ituri remains the most affected province, accounting for 85% (3979/4665) of all confirmed cases and 79% (1726/2184) of reported deaths nationwide.  

    As of 12 August, the proportion of contacts followed up in the last 24 hours is at 84.2% (17 460 seen out of 20 740 to follow up). 

    As of 9 August, infections among health workers continue, with at least 155 confirmed cases, including 45 deaths (CFR: 29%) and 68 recoveries since beginning of the outbreak. These infections highlight ongoing occupational exposure risks, persistent challenges in implementing infection prevention and control (IPC) in health-care facilities—especially outside of the designated Ebola treatment centres which have more established protocols and access to supplies--and continued exposure risk in the community. 

    The outbreak is taking place amid a severe humanitarian crisis and ongoing insecurity, characterized by large-scale population displacement, significant population mobility, and constrained access to critical services, including health care, safe water, food, shelter, and protection. 

    Response efforts in the affected provinces have been hindered by insecurity and attacks on health facilities, which have curtailed access for response teams, discouraging potential patients from seeking care, disrupting surveillance and response activities and increasing the risk of undetected transmission. 

    Since the declaration of the Ebola public health emergency of international concern (PHEIC) on 17 May 2026, 12 attacks on health care have been recorded, with additional reports under verification. These challenges underscore the importance of community-centred response efforts led by local authorities and trusted community leaders.  

Figure 2: Number of confirmed cases (n = 4665), in the Democratic Republic of the Congo, by date of reporting and as of 12 August 2026 

{Click on Image to Enlarge}

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Figure 3: Number of deaths among confirmed cases (n = 2184), in the Democratic Republic of the Congo, by date of reporting, as of 12 August 2026

{Click on Image to Enlarge}

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{*} Note that the large number of reported deaths on 22 July represents the completion of a data reconciliation exercise, including deaths that occurred earlier in the outbreak, rather than newly recorded deaths. 

Epidemiology

    Bundibugyo virus disease (BVD) is a severe Ebola disease caused by the Bundibugyo virus, one of the Orthoebolavirus species. It is a zoonotic disease, with fruit bats suspected to be the natural reservoir. 

    Human infection is thought to occur through close contact with the blood or secretions of infected wildlife, such as bats or non-human primates, and it subsequently spreads from person-to-person through direct contact with the blood, secretions, organs, or other bodily fluids of infected individuals or contaminated surfaces and materials. Transmission is particularly amplified in health-care settings when IPC measures are inadequate and during unsafe burial practices involving direct contact with deceased individuals. 

    The incubation period for BVD ranges from two to 21 days, and infected individuals are not infectious until symptom onset. Early symptoms such as fever, fatigue, muscle pain, headache, and sore throat are non-specific, which complicates clinical diagnosis and can delay detection. These symptoms then progress to gastrointestinal symptoms, organ dysfunction, and, in some cases, haemorrhagic manifestations. 

    CFRs in the past two BVD outbreaks, reported in Uganda and in the Democratic Republic of the Congo in 2007 and 2012, were 30% and 50%, respectively. 

    Differentiating BVD from other endemic febrile illnesses such as malaria is challenging without laboratory confirmation using PCR or antigen- or antibody-based assays. Outbreak control relies on rapid case identification, isolation and care, contact tracing, safe burials and strong community engagement, as no approved vaccines or specific treatments currently exist for BVD. 

Public health response

    For detailed information about the ongoing public health response actions by the respective Ministry of Health, WHO and partners please refer to the latest situation reports published by the WHO Regional Office for Africa: Ongoing outbreak in the Democratic Republic of the Congo | WHO | Regional Office for Africa | WHO| Regional Office for Africa  

    Health authorities in the Democratic Republic of the Congo, in collaboration with WHO and partners, are continuing to implementing extensive public health measures, including: 

    ° the continental preparedness and response plan, 

    ° a strategic six-month framework plan designed to guide coordinated efforts to strengthen outbreak response measures, including 

    ° emergency coordination, 

    ° disease surveillance, 

    ° laboratory testing, 

    ° infection prevention and control, 

    ° clinical care, 

    ° community engagement, 

    ° research, 

    ° logistics and support for essential health services, 

    ° engaging donors and mobilizing additional resources to address critical funding gaps and 

    ° sustain response operations across affected and at-risk areas. 

    A substantial scale-up is ongoing across all response pillars to get ahead of the outbreak.

WHO risk assessment

    On 6 June 2026, WHO reassessed the risk of the outbreak of BVD to incorporate newly available information and align with the WHO Temporary Recommendations. 

    The risk for countries sharing land borders with countries with documented Bundibugyo virus detection, the Democratic Republic of the Congo and Uganda at the time of assessment, was separated from the risk for other countries in the African Region. 

    The risk in the Democratic Republic of the Congo was assessed as very high due to ongoing transmission and the continued expansion of the outbreak into new health zones, increasing the potential for further national and regional spread. 

    The risk in Uganda was assessed as high due to confirmed cross-border spread through imported cases and ongoing epidemiological links along the eastern Democratic Republic of the Congo–western Uganda corridor, which has historically been affected by Ebola outbreaks, including Bundibugyo virus and Sudan virus disease.  

    The risk for countries sharing land borders with countries reporting BDBV detection was assessed as high due to sustained population mobility linked to cross-border trade and mining activities, variation in capacities and experience of BVD response, and variable levels of readiness.  

    The risk for the rest of the African region and at the global level was assessed as low. 

    For further information, please see the WHO Rapid Risk Assessment – Ebola disease caused by Bundibugyo virus, Democratic Republic of the Congo, Uganda and countries with land borders adjoining countries with documented BDBV detection v3. 

    An updated Rapid Risk Assessment is being developed in advance of the upcoming IHR Emergency Committee meeting regarding the epidemic of Ebola Bundibugyo virus disease in the Democratic Republic of the Congo scheduled for 18 August. This is the second meeting of the committee, following their initial meeting after the Director-General characterized the situation as a Public Health Emergency of International Concern on 17 May 2026.  

(...)

Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON615

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#USA, MDHHS confirms detection of #influenza A #H1N2 variant (#swine flu) in #Michigan resident (August 15 '26)

 

    LANSING, Mich. – The Michigan Department of Health and Human Services (MDHHS), Kent County Health Department (KCHD) and Ionia County Health Department have identified a human case of influenza A H1N2 variant (swine flu) in an Ionia County resident who was a swine exhibitor at the Kent County Youth Fair. 

    The fair took place Aug. 3-8 at the Grand Agricultural Center of West Michigan in Lowell.

    The individual tested presumptive positive at the MDHHS Bureau of Laboratories for swine flu and was confirmed by the Centers for Disease Control and Prevention (CDC) on Friday.

    MDHHS and KCHD have been reaching out to swine exhibitors and their families who visited the swine barns at the Kent County Youth Fair to identify any additional illnesses in those who may have been exposed to influenza from infected pigs. 

    KCHD has alerted providers in the area to watch for patients presenting with respiratory symptoms who report exposure to swine or visited the fair.

    “While the risk to the general public remains low, we want visitors who attended the Kent County Youth Fair to be alert to symptoms and take appropriate precautions,” said Dr. Natasha Bagdasarian, chief medical executive. 

    “Anyone who develops flu‑like symptoms after possible exposure should contact their health care provider and let them know about their recent contact with pigs at the fair. Individuals who are sick should stay home until they have fully recovered.”

    “It’s not unusual for flu viruses to occur in pigs, and while rare, those flu viruses can be transmitted to people by sick pigs,” said Dr. Nora Wineland, State Veterinarian, Michigan Department of Agriculture and Rural Development (MDARD). 

    “MDARD encourages exhibitors to follow disease prevention practices and work with their veterinarian if they suspect illness in an animal. It is still safe to enjoy your local fair, and visitors are encouraged to follow simple hygiene practices to help keep both people and animals healthy.”

    Pigs may be infected with swine influenza viruses that are different from human flu viruses. Swine flu viruses spread among pigs and – while rare – they can spread from pigs to people too. Spread of swine flu viruses from a pig to a person is thought to happen in the same way that human flu viruses spread; mainly through droplets when infected pigs cough and sneeze.

    MDHHS reiterates precautions the public can take to avoid potential exposure at farms, fairs and exhibits:

        ° Do not eat or drink in livestock barns or show rings.

        ° Do not take toys, pacifiers, cups, baby bottles, strollers or similar items into pig areas.

        ° Anyone who is at high risk of serious flu complications should avoid contact with pigs and swine barns when attending a fair.

        ° Get an annual influenza vaccination.

Below are some steps you can take to protect yourself and prevent the spread of any illness:

        ° Wash hands often with soap and water. If soap and water are not available, use an alcohol-based hand rub. 

        ° Avoid touching your eyes, nose and mouth. Germs spread this way. 

        ° Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it. 

        ° Avoid close contact with sick people. If you are sick, stay home from work or school until your illness is over.

        ° Avoid contact with pigs if you have flu-like symptoms. Wait seven days after your illness started or until you have been without fever for 24 hours without the use of fever-reducing medications, whichever is longer. 

    Symptoms of variant influenza infection in people are similar to those of seasonal flu viruses and may include:

        ° Fever.

        ° Cough.  

        ° Runny nose.

        ° Body aches.

        ° Nausea.

        ° Vomiting.

        ° Diarrhea.

    Variant influenza infections, including influenza A H1N2 can sometimes cause severe disease, even in healthy people.

    Severe illness can include complications, such as pneumonia, which may require hospitalization, and in some cases can result in death.

    People who are at high risk of developing complications if they get variant influenza infection include:

        ° Children younger than five years of age.

        ° People 65 years of age and older.

        ° Pregnant people.

    People with certain long-term health conditions, such as asthma, diabetes, heart disease, weakened immune systems and neurological or neurodevelopmental conditions.

    The time period it takes from exposure to illness for variant influenza is similar to that of seasonal influenza, which can be up to 10 days, but is most commonly three days. 

    Currently, there is no human vaccine for swine flu and the seasonal flu vaccine will not protect against swine flu; however, prescription antiviral drugs, such as oseltamivir and zanamivir, are effective in treating swine flu in humans. 

    Early treatment works best and may be especially important for people with a high-risk condition.

    For more information, visit CDC.gov/Swine-Flu.

Source: 

Link: https://www.michigan.gov/mdhhs/inside-mdhhs/newsroom/2026/08/14/mdhhs-confirms-detection-of-influenza-a-h1n2-variant-in-michigan-resident

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#Ebola is #winning: #Epidemic now killing one person every 30 minutes (UN News Centre, August 15 '26)

 

“Ebola is winning in the Democratic Republic of the Congo,” UN humanitarian affairs chief Tom Fletcher said. “We cannot let the virus outrun our response.” 

    Alongside the startling current fatality rate, Mr. Fletcher announced on Friday that he has allocated an additional $30.5 million from the UN’s Central Emergency Response Fund (CERF) – building on the $24 million previously allocated to the DRC and its neighbors to tackle the outbreak.

    The UN’s humanitarian office (OCHA) recently deployed a further 20 staff to the epicentre of the outbreak, but Mr. Fletcher said more may be needed to slow the spread. 

    Declared on 15 May by national authorities in the DRC, the Ebola Bundibugyo outbreak has now killed 2,184 people – nearly 47 per cent of those who have been infected. 

    Six of the DRC’s 26 provinces have recorded Ebola cases, and Uganda has reported 20 cases. 

    “This is a wake-up call,” Mr. Fletcher said.” We need speed, scale and solidarity before this virus gets even further ahead of us.” 

WFP expands food assistance 

    Starting tomorrow, the UN’s World Food Programme (WFP) will bring its hot meal programme to additional Ebola treatment centres in Ituri and other provinces, UN spokesperson Daniela Gross said on Friday. 

    Civilians in the North Kivu and South Kivu provinces are simultaneously dealing with Ebola and the ongoing conflict between the Congolese military and Rwanda-backed M23 militia. 

    Ituri province remains the heart of the outbreak; of the more than 4,660 cases total, Ituri has recorded over 3,400. 

    Across eastern DRC, 2.6 million people are seriously malnourished, with more than half located in Ituri. 

    Since the end of May, WFP has provided more than 260,000 hot meals at treatment and isolation centres in Ituri, North Kivu and South Kivu provinces. 

    Following Friday’s meeting of the UN’s Inter-Agency Standing Committee, Mr. Fletcher said the world’s largest humanitarian organisations had agreed to scale up the global Ebola response. 

More support needed 

    Still, Ms. Gross said that civilians’ needs in the DRC far outpace the Ebola response, and that more support is needed. 

    In order to protect lives across the region, Mr. Fletcher said the UN and its partners responding to Ebola must double the number of teams ensuring safe and dignified burials, triple the treatment capacity, improve contact tracing, and deploy more experienced managers. 

    They also need to keep providing water, hygiene and healthcare assistance to those affected by the both outbreak and the years-long conflict between multiple armed groups and national troops which is complicating the fight against Ebola. 

    Food insecurity assistance is only 25 per cent funded, highlighting the need for additional funding for lifesaving food aid. 

    “The world needs to wake up and show up,” Mr. Fletcher said. 

Source: 

Link: https://news.un.org/en/story/2026/08/1168148

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Innate Immune Responses Induced by #H9N2 #Influenza A Virus and #Klebsiella pneumoniae Co-Infection

 

Abstract

Klebsiella pneumoniae infection following H9N2 Influenza A virus (IAV) infection causes severe pneumonia. But the underlying pathogenic mechanisms of H9N2 IAV and K. pneumoniae co-infection are complex and need to be further explored. In this study, the lung transcriptomes of mice with H9N2 IAV and K. pneumoniae co-infection were characterized by transcriptomic profiling. As a result, GO enrichment analysis revealed that the differential genes were primarily involved in the activation of immune responses, cellular components of membranes and extracellular spaces, and defense responses against pathogen infections. According to KEGG enrichment, the differentially expressed genes (DEGs) were concentrated in TLR signaling pathways, RLR signaling pathways, TNF signaling pathways and NLRP3 signaling pathways. Furthermore, in vitro cell models were established to investigate the innate immune responses induced by H9N2 IAV and K. pneumoniae CPS co-stimulation. K. pneumoniae CPS stimulation influenced the cytokine profiles of mink lung epithelial cells infected with H9N2 IAV, worsened cell viability, and aggravated apoptosis, indirectly inhibiting H9N2 IAV replication. The findings demonstrated that K. pneumoniae superinfection modulated the innate immune responses induced by H9N2 IAV infection, contributing to its pathogenesis.

Source: 

Link: https://www.mdpi.com/1999-4915/18/8/900

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#Wastewater Data for Avian #Influenza #H5 (US CDC, August 14 '26)

 

{Excerpt}

(...)

A(H5) detections in the past week

Time Period: August 02, 2026 - August 08, 2026

    -- A(H5) Detection: 5 site(s) (1.2%)

    -- No Detection: 422 site(s) (98.8%)

    -- No samples: 88 site(s)

{Click on Image to Enlarge}

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(...)

Source: 

Link: https://www.cdc.gov/wastewater/emerging-viruses/h5.html?

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Seasonal #surveillance in #humans in 2026 for #WNV - Weekly Update (ECDC, August 14 '26): 429 cases so far, of which 224 in #Italy

 

{Summary}

Week 33, 2026 | Produced on 14 August 2026 at 06:00, based on data submitted up until and including 13 August 2026.

Current situation

    Since the beginning of the 2026 transmission season, and as at 13 August, 77 areas affected by West Nile virus (WNV) have been identified in nine countries across Europe.

    These areas are located in 

        § Italy (40), 

        § Greece (13), 

        § Romania (12), 

        § France (four), 

        § North Macedonia (three), 

        § Spain (two), 

        § Germany (one), 

        § Kosovo* (one) and 

        § Serbia (one).

    This week, 19 areas are reported as affected for the first time this season. (...)

    The nine countries have reported 429 locally acquired human cases of WNV infection: 

        § Italy has reported 224, 

        § Greece 105, 

        § Spain 42, 

        § North Macedonia 30, 

        § Romania 18, 

        § France six, 

        § Serbia two, 

        § Germany one and 

        § Kosovo* one case.

(...)

Source: 

Link: https://www.ecdc.europa.eu/en/west-nile-fever/surveillance-and-disease-data/disease-data-ecdc

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

 

The date of last occurrence corresponds to the end date of the most recent event involving backyard birds in Biobío region, involving birds that were not considered poultry as defined by the OIE Terrestrial Code.

Source: 

Link: https://wahis.woah.org/#/in-review/7757

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#Antibody #evasion and receptor binding of #SARS-CoV-2 variants #PQ.16.1.1 and RK.1

 

{Excerpt}

Since its rapid global spread beginning in late 2024, the SARS-CoV-2 variant NB.1.8.1 has progressively displaced older omicron variants, and has established near-total dominance in Asia. More recently, two NB.1.8.1-derived sublineages, PQ.16.1.1 and RK.1, have emerged and expanded substantially, particularly in China and Singapore (...). Specifically, the sublineage PQ.16.1.1 acquired the amino acid substitutions Asp253Gly (within the N-terminal domain), alongside Asn417Thr, Asp420Asn, and Ile478Thr (within the receptor-binding domain) relative to the parental NB.1.8.1 strain (...). Concurrently, the RK.1 sublineage (formally classified as a descendant of the PQ.17.7.2.1 branch) acquired Asp420Asn, His445Pro, and Ile478Thr (...). Furthermore, PQ.16.1.1 has continued to evolve into the SV series sublineages (predominantly SV.2 and SV.2.1), which have maintained all receptor-binding domain mutations, including Asp420Asn, and have subsequently come to dominate the circulating SARS-CoV-2 strains in Singapore (...).

(...)

In summary, the convergent acquisition of the Asp420Asn substitution in NB.1.8.1 sublineages again illustrates a classic SARS-CoV-2 receptor-binding domain evolution trade-off: a sacrifice in hACE2 receptor engagement in exchange for profound, targeted evasion of class 1 neutralising antibodies. (...) Given the increased evasion of class 1 antibodies by these Asp420Asn-carrying sublineages, these variants will likely spread from Asia and begin to prevail in countries where mRNA vaccination is common and populations are enriched with class 1 neutralising antibodies. 

Source: 

Link: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(26)00429-9/fulltext?rss=yes

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#Vaccine #imprinting drives increased #SARS-CoV-2 #variant infection in #children

 

Abstract

Virus exposure history, particularly first exposure, is believed to shape vaccine efficacy and infection susceptibility; however, evidence for mechanistic links between immune responses in individuals and epidemiological outcome in populations is scarce. Recent co-circulation of SARS-CoV-2 variants XFG and BA.3.2 has revealed a striking enrichment in BA.3.2 cases among children. By combining epidemiological modeling, serology and monoclonal antibody analysis in children and adults, we show the dependence of effective variant-specific antibodies on vaccination history which may explain birth-year influence on differential susceptibility to these co-circulating variants. Ancestral cross-reactive site I antibodies frequently neutralize BA.3.2, but not XFG. By contrast, Omicron type-specific site I/III and III antibodies frequently neutralize XFG but not BA.3.2, revealing a tradeoff in the ability to neutralize these two co-circulating strains. These findings mechanistically link immune history, variant neutralization, antibody repertoire and variant infection risk, and suggest that vaccination regimens in children should prioritize neutralization breadth.

Competing Interest Statement

E.J.W. advises Arpelos Bioscience, Arsenal Biosciences, Coherus, Danger Bio, IpiNovyx, New Limit, Marengo, Pluto Immunotherapeutics Related Sciences, Santa Ana Bio, and Synthekine. E.J.W. is a founder of and holds shares of Coherus, Danger Bio, and Arsenal Biosciences. All other authors declare no competing interests.

Funder Information Declared

National Institute of Allergy and Infectious Diseases, https://ror.org/043z4tv69, 75N93021C00015, U19AI082630, AI105343, AI108545, AI155577, AI149680

National Cancer Institute, 75N91019D00024, 75N91022F00005, 75N91023F00016

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.08.12.739589v1

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Identification and characterization of #PB2 #mutations associated with #mammalian #adaptation of highly pathogenic #H5N1 avian #influenza viruses

 

Abstract

The highly pathogenic avian influenza virus (HPAIV) subtype H5N1 has been continuously circulating among wild bird populations and domestic poultry. It’s ongoing circulation has led to outbreaks in poultry and U.S. dairy cattle populations, as well as sporadic severe infections in individuals engaged in poultry and dairy farming. These occurrences have raised concerns about the potential evolution of this virus into a pandemic strain. To elucidate the molecular determinants facilitating H5N1 cross-species adaptation and to evaluate its implications for public health, we conducted serials of sequence analysis and specific-site mutations on the viral polymerase subunit PB2 to determine its effect on polymerase activity and viral infectivity. The results showed that three mutations in the PB2 protein (E362G, D441N and M631L) were presented cooperative effects associated with enhanced viral replication in mammalian cells. Compared to the original isolated strain of the 2.3.4.4b clade, A/chicken/NL/FAV-0033/2021, these three mutations were predominantly identified in isolates obtained from cattle and other mammalian hosts between 2021 and 2024. The M631L mutation, identified as the primary determinant of increased polymerase activity in mammalian cells, significantly enhanced the binding affinity of PB2 to ANP32A. The mutation E362G and D441N did not increased polymerase activity and viral replication significantly but enhanced binding affinity of PB2 to ANP32A. The combined mutations with E362G, D441N and M631L resulted in a significantly increased polymerase activity and viral replication in H5N1 virus, and significantly elevated viral loads and aggravated pulmonary pathology in lungs of mice with H5N1 infection. These findings indicate that the PB2-M631L mutation constitutes a crucial molecular marker for the adaptation of H5N1 to mammalian hosts, whereas the E362G and D441N mutations likely function as supportive modulatory factors that optimize this host-adaptation process.

Source: 

Link: https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2026.1867604/full

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False-Reactive Fourth-Generation #HIV #Screening Results Before, During, and After #COVID19 #Pandemic in a High-Prevalence Urban Medical Center

 

Highlights

    • False-reactive HIV screens increased during the COVID-19 pandemic

    • Elevated HIV false-reactive proportions persisted post-pandemic

    • False-reactive HIV screens are predominantly low S/CO values

    • Age, race/ethnicity, and syphilis infection were associated with false-reactive results

    • Unresolved reactive screens reveal gaps in reflex nucleic acid test completion

Abstract

Objective

False-reactive results of the fourth-generation HIV-1/2 antigen/antibody (Ag/Ab) Combo assay trigger additional testing, increased costs, and patient anxiety. Large-scale analyses of false-reactive results spanning the COVID-19 pandemic in high-prevalence communities are lacking. This study aims to investigate the frequency of false-reactive HIV-1/2 Ag/Ab Combo screening results before, during, and after the COVID-19 pandemic and to identify associated patient factors.

Design

We conducted a retrospective study of HIV-1/2 Ag/Ab Combo assays performed from 2019 – 2024 at a tertiary care medical center in Baltimore, MD. False-reactive proportions were compared across pre-pandemic (January – December 2019; n=12,347), pandemic (January 2020 – June 2023, n=33,546), and post-pandemic (July 2023 – December 2024; n=12,238). Associations between false-reactive results and selected patient factors were assessed.

Results

Among 58,131 screens, 1,236 (2.1%) were reactive; 185 were false-reactive, yielding a false-reactive proportion of 15.0% among reactive results. The false-reactive proportion increased from 5% pre-pandemic to 17.9% at the onset of the COVID-19 pandemic and remained near 20% during the pandemic, declining to approximately 14% by 2024 post-pandemic. In multivariable analysis, age >65 or <21, White race, and American Indian/Alaska Native race were associated with higher odds of false-reactive results, whereas coinfection of syphilis was associated with lower odds. Most false-reactive results clustered at low signal-to-cutoff ratio (S/CO) values.

Conclusions

False-reactive HIV Ag/Ab screening results increased during the pandemic and remained elevated afterward. Associated factors analysis and S/CO distributions may help interpretation of questionable reactive screens. Our findings reinforce the importance of reflex HIV nucleic acid testing (NAT) for discordant results.

Source: 

Link: https://www.sciencedirect.com/science/article/abs/pii/S138665322600082X?dgcid=rss_sd_all

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Protective Efficacy Evaluation of Various Inactivated #Vaccines Against the Newly Circulated Highly Pathogenic Avian #Influenza Virus #H5N1 of Clade 2.3.4.4b in Pekin #Ducks

 

Abstract

Highly pathogenic avian influenza (HPAI) virus H5N1of clade 2.3.4.4b has emerged as the predominant lineage circulating in poultry flocks worldwide, raising concerns regarding the protective efficacy of currently available commercial vaccines, particularly in domestic ducks, which play an important role in virus maintenance and transmission. Thus, this study evaluated the immunogenicity along with the protective efficacy of four inactivated H5 vaccines against a recently isolated local HPAI-H5N1 (Newvalley-3-H5N1-2024, clade 2.3.4.4b) strain in Pekin ducks in Egypt. A total of 150 seronegative ducks were divided into vaccinated and control groups (10 groups) and vaccinated at 10 days of age. At 31 days of age, the vaccinated and positive control groups were challenged using 106.5 EID50/0.5 mL/duck with the local isolate (Newvalley-3-H5N1-2024) via the oculo-nasal route. The vaccine efficacy was assessed through clinical signs, survival rate, hemagglutination inhibition (HI) antibody titer, tracheal and cloacal viral shedding quantified by real-time RT-PCR, and histopathological examination of trachea, lung, pancreas, and brain tissues. Generally, all ducks vaccinated with the ValleyVac Avian Flu H5 plus and MEFLUVACTM H5 PLUS 8 showed a significantly higher survival rate (100%) at 10 days post-vaccination (DPV) than those in the positive control (66.7% mortality rate). In contrast, ducks exhibited mortality rates ranging from 6.7% in the SERVAC Flu H5N1 group to 13.4% in the Sinder Fluvac group. The ValleyVac Avian Flu H5 plus and MEFLUVAC™ H5 PLUS 8 vaccines induced the highest HI antibody titers at 7, 14, 21, and 28 DPV in both homologous and heterologous AIV antigens, resulting in a significant reduction in viral load among all vaccinated duck groups (p-value < 0.05) comparable to the positive control group. Conversely, the SERVAC Flu H5N1 and Sinder Fluvac vaccines provided partial protection, suboptimal immunogenicity at different time points, and elevated viral shedding. Histopathological findings in ValleyVac Avian Flu H5 plus and MEFLUVAC™ H5 PLUS 8 vaccines exhibited mild tissue alterations following AIV challenge. Marked pathological lesions were observed in the SERVAC Flu H5N1 and Sinder Fluvac vaccinated groups. Among tested vaccines, both ValleyVac Avian Flu H5 plus and MEFLUVACTM H5 PLUS 8 showed the highest level of protective efficacy against the circulating AIV strain compared with other commercial vaccines. This study highlights the need for continuous molecular surveillance, antigenic matching, and regular updating of vaccine seed strains to ensure efficient HPAI control in Egypt.

Source: 

Link: https://www.mdpi.com/1999-4915/18/8/891

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Seasonal #surveillance in #humans and #animals in 2026 for #WNV, Monthly Report (ECDC, August 12 '26): 245 cases so far

 

August 2026 | Produced on 12 August 2026 at 12:00 based on data submitted up until and including 5 August 2026

Epidemiological summary

Findings from human surveillance

    In 2026, and as at 5 August, seven countries in Europe have reported 245 locally acquired {1} human cases of West Nile Virus (WNV) infection. 

    The earliest and latest date of onset were on 12 May 2026 and 1 August 2026, respectively. 

    Locally acquired cases have been reported by Italy (139 cases), Greece (65, of which four with unknown place of infection), Spain (17 cases), North Macedonia (13 cases), Romania (six cases), France (four cases) and Germany (one case). 

    In Europe, 12 deaths have been reported by Greece (six deaths), Italy (five deaths) and Romania (one death).

    The number of human cases reported so far (245 cases) is below the average for the corresponding period over the past decade (403 cases). 

    However, reporting delays may result in an under-estimation of the current burden, as the 2026 data remain provisional, whereas the ten-year average is based on consolidated data from previous years. 

    In addition, this ten-year average is influenced by several particularly intense WNV transmission seasons, notably in 2018 (1 065 cases reported up to the corresponding week), 2022 (781 cases) and 2024 (654 cases).

    To date, most cases have been reported in Italy (139 cases) and Greece (65 cases). 

    Although the number of cases reported in Italy is lower than during the same period in 2025 (168 cases), it remains the most affected country in Europe in 2026. 

    Greece has reported more cases in 2026 than during the same period in 2025 (65 cases compared with 26 cases). 

    WNV circulation is currently most intense in the Attica NUTS 2 region (48 cases), with Anatoliki Attiki (East Attica, 34 cases) and Voreios Tomeas Athinon (North Athens, seven cases) most affected.

    As at 5 August 2026, locally acquired human cases of WNV infection had been reported in 58 NUTS 3 regions across seven countries. 

    This is higher than at the same point in 2025, when cases were reported in 40 NUTS 3 regions across six countries. 

    However, the geographical spread observed so far in 2026 remains well below the final extent recorded in recent seasons: by the end of 2025, affected regions numbered 160 and in 2024 there were 218. 

    The 2024 season remains the largest WNV season on record in terms of geographical spread.

    This year, six regions reported locally acquired human cases of WNV infection for the first time ever: France in Pyrénées-Orientales (FRJ15); Germany in Rhein-Pfalz-Kreis (DEB3I); Italy in Campobasso (ITF22) and Viterbo (ITI41); North Macedonia in Pelagoniski (MK005) and Vardarski (MK001).

    Similar to previous years, most cases were reported among males aged 65 years and above. 

    Most cases were hospitalised (72%) and presented with neurological symptoms (58%). 

    The proportion hospitalised was lower than the average reported during the previous decade (87%), while the proportion with neurological symptoms was also slightly lower than the historical 10-year average (64%). 

    The case fatality rate was approximately 5%, lower than the average reported during the previous decade (11%). 

    However, this estimate should be interpreted with caution, as clinical outcomes may not yet be known for all reported cases and additional deaths may be recorded as the season progresses and data are consolidated.

    Owing to delays in diagnosis and reporting, and because most WNV infections are asymptomatic or subclinical, the reported case numbers probably underestimate the true number of infections. Seasonal surveillance in humans primarily captures laboratory-confirmed cases, which may further contribute to reporting delays.

Findings from veterinary surveillance

    From the veterinary perspective, 17 WNV outbreaks among equids and 74 outbreaks among birds have been reported in Europe in 2026. 

    The earliest start date of an outbreak among equids and birds was on 30 March 2026 in France and 31 March 2026 in Italy, while the latest onset of an outbreak among equids and birds was, respectively, on 31 July 2026 in Netherlands and 28 July 2026 in Italy. 

    Outbreaks among equids have been reported by France (five outbreaks), Greece (five outbreaks), Italy (five outbreaks), the Netherlands (one outbreak) and Spain (one outbreak). 

    Outbreaks among birds have been reported by Italy (64 outbreaks), France (five outbreaks), Spain (three outbreaks), Austria (one outbreak) and Belgium (one outbreak).

    No information was available on the equid species involved in the outbreaks reported in the Animal Disease Information System (ADIS). 

    The bird species most frequently associated with the reported outbreaks were the common magpie (23) and the hooded crow (20), followed by the carrion crow (5), the common kestrel (5), the Eurasian blackbird (5), the yellow-legged gull (3), Adalbert’s eagle (2), the common wood-pigeon (2), and the little owl (2). 

    Single outbreaks were associated with the common loon, the common raven, the European turtle-dove, the golden eagle, the grey heron, the house sparrow and the northern goshawk.

    The monthly number of WNV outbreaks in equids reported during the first part of 2026 was comparable to the corresponding 10-year monthly average (2016−-2025). 

    However, the number of equid outbreaks in July 2026 remained below the levels observed in July 2018, 2024 and 2025, years characterised by particularly high WNV intensity. 

    In contrast, the number of WNV outbreaks in birds slightly exceeded the corresponding four-year monthly average (2022–2025) in April and May, and was substantially higher in June. 

    This trend reversed in July 2026, when the number of reported outbreaks in birds fell below the four-year average, although it remained higher than in July 2025. However, it should be noted that reporting delays may affect the July numbers, as some outbreaks occurring during that month may be notified in August.

    As at 5 August 2026, outbreaks in birds and/or equids have been reported in 43 NUTS 3 regions across seven countries. This compares with 55 regions (10 countries) during the same period in 2025 and 42 regions (eight countries) in 2024. All seven countries reported WNV outbreaks in birds and/or equids in 2025 and in prior years, reflecting endemic WNV activity in these territories. However, as at 5 August, outbreaks in birds and/or equids were reported to ADIS for the first time in the following six regions: by France in Hauts-de-Seine (FR105) and Seine-et-Marne (FR102); by Belgium in Arr. Namur (BE352), by Greece in Drama (EL514), by Italy in Genova (ITC33) and by the Netherlands in Delf en Westland (NL362).

Patterns across human and veterinary surveillance

    Four countries – France, Greece, Italy, and Spain – reported both human WNV infections and outbreaks in equids and/or birds. 

    As at 5 August, Italy accounted for most of the reported human cases (56.7%) and animal outbreaks (75.8%). 

    Greece reported the second-largest share of human cases (26.5%) but only five equid outbreaks and no bird outbreaks, representing 5.5% of all reported animal outbreaks.

    Differences in the patterns observed across European countries may reflect a combination of ecological, climatic and surveillance-related factors. 

    Favourable climatic conditions and the presence of ecological hotspots, such as wetlands and agricultural areas, may support mosquito vector populations and influence the distribution and behaviour of animal hosts, thereby facilitating WNV circulation. At the same time, differences in WNV surveillance systems across Europe may affect detection and reporting rates.

    The first indication of WNV activity may arise from either human or animal surveillance, depending on local epidemiology, detection capacity and surveillance system sensitivity. Therefore, the absence of reports from one sector should not be interpreted as evidence that WNV is not circulating. 

    In France (Pyrénées-Orientales, FRJ15), Greece (Drama, EL514), and Italy (Genova, ITC33), human cases were reported before, or in the absence of, notified outbreaks in birds or equids. 

    Conversely, in Belgium (Arr. Namur, BE352), France (Hauts-de-Seine, FR105 and Seine-et-Marne, FR102) and the Netherlands (Delft en Westland, NL362), animal detections preceded human cases. 

    Belgium is a relevant example, as WNV was first reported in the country in 2025 through avian surveillance, with no previous detections in humans and animals. In 2026, it has again been identified in birds in a previously unaffected region, highlighting the role of avian surveillance in detecting local virus circulation and geographical spread.

    Active mosquito surveillance is also important for the early detection of WNV circulation. However, results on WNV detection in mosquitoes are not included in this report because they are not legally required to be reported at European level, and the available information is therefore scattered and often project-based.

Seasonal outlook

    Given the favourable weather conditions for WNV transmission in Europe, ECDC and EFSA expect further human cases and outbreaks in equids and birds to be reported in the coming weeks. In previous years, transmission has typically peaked in August and September.

    ECDC and EFSA continue to closely monitor the situation in Europe.

(...)

Source: 

Link: https://www.ecdc.europa.eu/en/infectious-disease-topics/west-nile-virus-infection/surveillance-and-disease-data/monthly-updates

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