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ABSTRACT Recently, human infections with H10 influenza viruses, including H10N8 and H10N3, have been reported. In January 2024 , a case of H10N5 and H3N2 co-infection was reported in Zhejiang Province, China , which is the first human infection with H10N5 avian influenza virus (AIV) globally. Almost simultaneously, we isolated a wild bird-derived H10N5 strain similar to the human H10N5 strain. To assess the public health risk , it is necessary to understand the zoonotic characteristics of these novel H10N5 viruses. Here, we evaluated the biological characteristics of human H10N5 , wild bird H10N5, as well as poultry H10N8 in vitro and in vivo. We demonstrate that the novel H10N5 isolates infected and replicated effectively in human lung epithelial cells . They infected BALB/c mice without adaptation , which exhibited robust pathogenicity and caused mouse death. In guinea pig transmission experiments , the H10N5 strain spread through neither direct contact nor airborne exposure , wherea...

LETTER Highly pathogenic avian influenza (HPAI) viruses of genotype B3.13 were first reported in dairy cattle in March 2024 and, by 4 March 2025, had infected at least 989 cattle herds in 17 states in the US ( https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/hpai-confirmed-cases-livestock ; accessed on March 24, 2025). Importantly, spillover infections of poultry and mammalian species , including cats and humans , have occurred ( https://www.cdc.gov/bird-flu/situation-summary/index.html ; accessed on 4 March 2025). Texas reported several infected herds in the spring (1) and early summer of 2024 but saw fewer outbreaks during the second half of 2024, with reported outbreaks in July and December (2). Since September 2024, almost all reported outbreaks of genotype B3.13 viruses in dairy cattle have occurred in California . Here, we characterized self-submitted samples from a farm in Texas that experienced an outbreak in December 2024. This farm ha...

Highlights •  This study evaluated differences in SARS-CoV-2 variant severity from 2020-2023 •  SARS-CoV-2 whole-genome sequencing from 6,916 respiratory swabs was performed •  Four conserved kmer sequences associated with severity were identified •  Infections from the Delta variant had highest likelihood of severe infection •  Omicron BA.4/5 variant was more severe than BA.1 in children, vice-versa in adults Abstract We performed virus whole-genome sequencing of 6,916 upper respiratory swabs from adults and children from March 2020 through May 2023 and collected clinical metadata to assess differences in SARS-CoV-2 variant severity and symptomatology. Multivariable logistic regression showed a severity peak with Delta , which had the highest likelihood of severe infection. In children , another peak was observed with BA.4/BA.5 , which was associated with more severe infection than both prior ( BA.1 ) and later ( BQ.1, BF.7, and XBB ) Omicron variants . In cont...

Summary The recent emergence of highly pathogenic H5N1 avian influenza virus infections in dairy cows and humans in the U.S. has raised alarms regarding the potential for a pandemic . Over 995 dairy cow herds and at least 70 humans have been affected, including cases of severe disease and the first reported H5N1-related death in the U.S . Sporadic human infections with no known contact with infected animals highlight the possibility of viral adaptation for efficient human-to-human transmission. Concurrently, the virus continues to circulate in wild birds, backyard flocks, and hunted migratory species , further amplifying the risk to humans and domestic animals. This article provides an overview of the current outbreak status , emphasizes the importance of robust surveillance systems to detect emerging strains with pandemic potential, and highlights risks to the U.S. dairy and poultry industries. Recommendations for risk mitigation include enhanced biosecurity measures, improved surveil...

Summary Background mRNA-1283 is an investigational, next-generation COVID-19 vaccine that encodes only the immunodominant regions of the SARS-CoV-2 spike protein —the receptor-binding domain (RBD) and the N-terminal domain rather than the full-length spike used in currently authorised mRNA vaccines. We evaluated the relative vaccine efficacy (rVE), immunogenicity, and safety of mRNA-1283 compared to the first-generation vaccine (mRNA-1273). Methods This randomised, observer-masked, active-controlled, phase 3 trial (NextCOVE) was conducted in individuals (aged ≥12 years) with no evidence of SARS-CoV-2 infection within 90 days of screening in the USA, the UK, and Canada. Participants were randomly assigned in a 1:1 ratio to receive one 10 μg dose of the bivalent formulation of mRNA-1283 (original plus omicron BA.4/BA.5) or 50 μg of the bivalent mRNA-1273, encoding the same variants. Randomisation was stratified by age (12–17 years, 18–64 years, and ≥65 years). Primary objectives comparin...

Abstract Collection of systemic tissues from influenza A virus (IAV)-infected ferrets at a fixed timepoint post-inoculation represents a frequent component of risk assessment activities to assess the capacity of IAV to replicate systemically. However, few studies have evaluated how the frequency and magnitude of IAV replication at discrete tissues contribute to within-host phenotypic outcomes, limiting our ability to fully contextualize results from scheduled necropsy into risk assessment settings. Employing aggregated data from ferrets inoculated with > 100 unique IAV ( both human- and avian-origin viruses, spanning H1, H2, H3, H5, H7, and H9 subtypes ), we examined relationships between infectious virus detection in four discrete tissue types ( nasal turbinate, lung, brain, and olfactory bulb [BnOB]) to clinical outcomes of IAV-inoculated ferrets, and the utility of including these discrete tissue data as features in machine learning (ML) models. We found that addition of viral ti...

Abstract Panzootic spillover of H5N1 virus clade 2.3.4.4b has resulted in expanded host range among placental mammals , with lactation transmission via milk documented. Whether infection during pregnancy leads to in utero or lactational vertical transmission remains unknown. Pregnant outbred mice were infected with A/bovine/Ohio/B24OSU-472/2024 during the second or third trimester equivalent. Second trimester infection caused in utero infection , with infectious virus detected in the uterus, placenta, and fetus . Birth following third trimester infection resulted in offspring with decreased size and neurodevelopmental delays , with infectious virus detected in the neonatal milk ring and lungs as well as mammary tissues . Ongoing H5N1 infections present increased risk for human exposure and an H5N1 vertical transmission model in placental mammals is essential for understanding viral spread and evaluating treatments during pregnancy. Source: BioRxIV,  https://www.biorxiv.org/content/...