ETIDIOH - NEW

  Abstract Up-to-date estimates of COVID-19 vaccine effectiveness (VE) are needed to inform COVID-19 vaccination strategies and recommendations . This target trial emulation study aimed to estimate the long-term vaccine effectiveness (VE) of the 2024-2025 COVID-19 vaccines targeting the KP.2 Omicron variant within the Veterans Health Administration . The study population (90.9% male, mean age 70.7 years) included 538,631 pairs of vaccinated (i.e., received the KP.2 COVID-19 vaccine) and matched unvaccinated (i.e., did not receive the KP.2 COVID-19 vaccine) persons enrolled from August 2024 to January 2025. Over a mean follow-up of 172 days (range 97-232) extending to April 12, 2025, VE was low against laboratory-diagnosed SARS-CoV-2 infection ( 16.60%, 95% confidence interval [CI], 11.92-21.44), SARS-CoV-2-associated emergency department/urgent care (ED/UC) visit ( 21.05%, 95% CI, 14.22-27.21), SARS-CoV-2-associated hospitalization ( 19.53%, 95% CI 6.56-30.10) and much higher again...

  Situation at a glance Since the beginning of 2025 and as of 21 December 2025, a total of 19 cases of Middle East respiratory syndrome coronavirus (MERS- CoV), including four deaths have been reported to WHO globally.  Of the 19 cases, 17 were reported by the Kingdom of Saudi Arabia (KSA), and two were reported from France .  Between 4 June and 21 December 2025, the Ministry of Health (MoH) of KSA reported a total of seven cases of MERS-CoV infection, including two deaths .  In addition , at the beginning of December 2025, the National IHR Focal Point (IHR NFP) for France also reported two MERS-CoV travel – associated cases ; involving individuals with recent travel to countries in the Arabian Peninsula.  The notification of these latest cases does not change the overall risk assessment , which remains moderate at both the global and regional levels .  These cases show that the virus continues to pose a threat in countries where it is circulating in dromed...

  {Eurasian Teal} {Eurasian Wigeon} {Mute Swan} ___ This is a new event opened to report outbreaks for which the N subtype could not be determined due to insufficient diagnostic material; in these cases, only the presence of H5 can be confirmed. Three Common Teals (Friuli Venezia Giulia, Lombardy) , two Eurasian Wigeons (Friuli Venezia Giulia), one Mute Swan (Lombardy).  Source:  Link:  https://wahis.woah.org/#/in-review/7144 ____

  The Official Veterinary Service (OVS) of the state of Mato Grosso received a notification of a suspected case influenza A viruses of high pathogenicity in domestic birds from a multi-species backyard , on December 20, 2025. Official Laboratory (LFDA-SP) analysis confirmed the presence of the H5N1 virus, clade 2.3.4.4b. The premises have been placed under quarantine. Birds will be culled, and carcasses, products, and any potentially contaminated materials will be destroyed. The OVS is currently conducting an epidemiological investigation in the surrounding area. Source:  Link:  https://wahis.woah.org/#/in-review/7147 ____

  Abstract Since 2021, highly pathogenic avian influenza viruses (HPAIV) belonging to H5N1 clade 2.3.4.4b have caused high mortality in North American wild birds and poultry . In 2025 , a new D1.1 genotype caused two human deaths and host-switched to dairy cattle . However, the evolutionary origins and dynamics of D1.1 have not been fully characterized. Here, our phylogenetic analysis of 17,516 H5N1 genome sequences uncovers how D1.1 introduced a major shift in the antigenic diversity and ecology of the H5N1 epizootic in North America. D1.1 is the first major H5N1 genotype to (a) emerge in the Pacific flyway and spread west-to-east faster than any prior genotype; (b) antigenically shift via reassortment with the North American N1 segment, displacing the previously fixed Eurasian N1 ; and (c) transmit to a broader range of host species than any H5N1 genotype to date, introducing mammalian adaptations . Competing Interest Statement The authors have declared no competing interest. Fun...

  ABSTRACT The 2009 pandemic H1N1 (pH1N1) influenza A virus (IAV) is a reassortant virus with two polymerase components, PA and PB2, originating from avian IAV . Avian IAV polymerase does not function efficiently in mammalian cells without host-adaptive mutations . The mechanism by which pH1N1 replicates in human hosts is not fully elucidated , as pH1N1 does not contain the host-adaptive PB2 E627K mutation required for species-specific interaction with ANP32 , which facilitates replicase (polymerase oligomer) formation. Our previous research revealed that mutations in PA played a key role in mammalian host adaptation of pH1N1. These mutations were found in two separate domains of PA, the C-terminal (CTD) and N-terminal domains (NTD). We reported that the NTD mutations increase the expression of NP through enhanced association of GRSF1 with the mRNA transcripts. However, the role of CTD mutations, which are located at the interface of the polymerase oligomers , has not been elucidat...

  Abstract Influenza D virus (IDV) is prevalent in cattle in China , and a risk for spillover to other species exists. We detected IDV antibodies in 6/315 of black donkeys in northern China , suggesting cattle-to-donkey transmission and demonstrating the expanding host range of IDV and the need for reassessment of cross-species transmission risks. Source:  Link:  https://wwwnc.cdc.gov/eid/article/31/12/25-0666_article ____

  Abstract Poultry workers in Washington, USA, were infected with highly pathogenic avian influenza A(H5N1) virus and recovered. The viruses were clade 2.3.4.4b genotype D1.1, closely related to viruses causing poultry outbreaks . Continued surveillance and testing for influenza A(H5) clade 2.3.4.4b viruses remain essential for risk assessment and pandemic preparedness of zoonotic influenza viruses. Source:  Link:  https://wwwnc.cdc.gov/eid/article/31/12/25-1118_article ____

{Excerpt}  Avian influenza A(H9N2) :  -- Guangdong Province :  1) An individual with onset in November 2025.  -- Guangxi Zhuang Autonomous Region :  2) An individual with onset in November 2025.  -- Hubei Province:  3) An individual with onset in November 2025.  (...) Source:  Link:  https://www.chp.gov.hk/files/pdf/2025_avian_influenza_report_vol21_wk51.pdf ____

  Abstract Many pathogens, both those with human spillover potential as well as avian-specific viruses, are maintained in wild bird populations . While much surveillance for influenza A viruses (IAVs) is performed annually, surveillance for other pathogens is limited. Sampling of wild birds is often time-consuming , labour-intensive, involves physically handling wild birds, often limited in sample size, and involves handling of potentially infected birds , posing an increased risk of direct exposure for personnel. Given this, additional methods for surveillance are needed. Longitudinal, bi-weekly fecal and sediment sampling was performed at various sites in southern Manitoba, Canada , particularly focused in Winnipeg from May - October 2025. Sites were chosen based on the suitability of the area for waterfowl habitat , the presence of waterfowl in the area, as well as sites in proximity to reported outbreaks of H5N1 influenza virus . Fecal and sediment samples were collected and sc...

  Abstract The recent emergence of highly pathogenic H5N1- especially clade 2.3.4.4b has led to widespread mortality in poultry and wild birds and has raised significant concerns for the dairy industry and human health. Migratory waterfowl are considered the main source of infection, and we used publicly available surveillance data and bird observation data from continental North America to show clear seasonal signals correlated with waterfowl movement, both on the continental scale and in three of the four flyways . In early 2024, the virus expanded its host range , and we observed a phase transition with the loss of the seasonal signal coupled with a concomitant increase in the proportion of mammalian cases . We also identified a second harmonic , with a regional east-to-west movement with infections spreading between regional flyways , followed by local viral amplification. We likened this to the movement of balls in a Newton's Cradle with an analogy between potential and viral ...

  Abstract In a new study, Zhao et al. (2025) obtain 959 whole genome sequences of H1N1 subtype swine influenza virus (SIV) isolated from China . Their analysis of the sequences , isolated between 1977 and 2020, reveals how H1N1 lineages have co-evolved and contributed to instances of zoonotic transmission within the region. This study’s findings characterize the long-term evolutionary effects of frequent viral reassortment in SIV and highlight its potential to drive future pandemics. Source:  Link:  https://academic.oup.com/evolut/advance-article/doi/10.1093/evolut/qpaf262/8400336 ____

{Summary} Highlights     • All clades of monkeypox virus (MPXV) continue to circulate.  - Unless mpox outbreaks are rapidly contained and human-to-human transmission is interrupted , there is a risk of sustained community transmission .   • In November 2025, 48 countries across all WHO regions reported a total of 2150 new confirmed mpox cases , including five deaths ( case fatality ratio [CFR] 0.2%).  - About 68% of these cases were reported in the African Region .  - Four regions observed a decline in confirmed cases in November, compared to October 2025, while the European and Western Pacific regions reported more cases than the previous month.      • Nineteen countries in Africa reported active transmission of mpox in the last six weeks (2 November– 14 December 2025), with 1435 confirmed cases , including seven deaths (CFR 0.5%).  - Countries reporting the highest number of cases in this period are the Democratic Republic of the ...

  Influenza at the human-animal interface  Summary and risk assessment, from 6 November to 19 December 2025 {1} -- New human cases {1,2}:  - From 6 November to 19 December 2025, based on reporting date , the detection of influenza A( H5N1 ) in one human , A( H5N5 ) in one human , A( H9N2 ) in seven humans , and an influenza A( H1N1 ) variant virus in one human were reported officially.  - In addition , one human case of infection with an influenza A( H1N2 ) variant virus was detected.  -- Circulation of influenza viruses with zoonotic potential in animals :  - High pathogenicity avian influenza (HPAI) events in poultry and non-poultry animal species continue to be reported to the World Organisation for Animal Health (WOAH).{3}  - The Food and Agriculture Organization of the United Nations (FAO) also provides a global update on avian influenza viruses with pandemic potential.{4}  - Additionally, low pathogenicity avian influenza viruses as well a...