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Showing posts from July 16, 2025

Detection of low pre-existing humoral #immunity against #influenza virus #H5N1 clade 2.3.4.4b in unexposed individuals

Abstract The spill-over of Influenza A virus H5N1 clade 2.3.4.4b from cattle to humans highlights the risk of a human H5N1 pandemic . Given the impact of pre-existing immunity on the course and severity of viral infections, we comprehensively assessed the humoral immunity against the H5N1 A/Texas/37/2024 isolate in H5N1- naive individuals . To this end, we performed complementary binding and neutralization assays on 66 subjects and ranked activities among a panel of 76 influenza A virus isolates. We detected low but distinct cross-neutralizing titers against A/Texas/37/2024 with a 3.9 to 15.6-fold reduction compared to selected H1N1 or H3N2 strains. By cloning and evaluating 136 monoclonal antibodies from memory B cells, we identified potent A/Texas/37/2024-neutralizing monoclonal antibodies in five out of six investigated individuals. These antibodies cross-neutralize H1, compete with antibodies targeting the HA stem, and protect mice from lethal H5N1 challenge. Our findings demonstra...

Development of #DNA and #mRNA-LNP #vaccines against an #H5N1 clade 2.3.4.4b #influenza virus

ABSTRACT Effective vaccines are an important public health tool which may be needed to combat the emerging, highly pathogenic H5N1 avian influenza viruses currently circulating in cattle and poultry in the United States . While nucleic acid-based vaccines such as mRNA -lipid nanoparticles (LNPs) have several potential advantages during a viral epidemic compared to traditional seasonal influenza vaccines , their utility and efficacy against H5N1 viruses remain incompletely defined. Here, we developed novel DNA- and mRNA-LNP-based vaccines encoding both hemagglutinin (HA) and neuraminidase (NA) proteins from the human-isolated highly pathogenic avian influenza H5N1 strain, A/Texas/37/2024, in a single open reading frame. This dual-antigen expression approach elicited strong protective immune responses targeting both the HA and NA proteins and provided complete protection against lethal viral challenges in a murine model . The pre-clinical data described in this work suggest that these mu...

Low levels of #H5N1 HA and NA #antibodies in the #human population are boosted by seasonal #H1N1 #infection but not by #H3N2 infection or influenza #vaccination

Abstract An increase in the number of human cases of influenza A/H5N1 infection in the US has raised concerns about the pandemic potential of the virus . Preexisting population immunity is a key determinant for risk assessment and pandemic potential for any virus. Antibody responses against the bovine A/H5N1 hemagglutinin (HA) and neuraminidase (NA) proteins were measured among a population of influenza-vaccinated or influenza-infected individuals . Modest titers of bovine A/H5N1 HA-binding antibodies and low to undetectable neutralizing antibody responses were detected in a cohort of 73 individuals . Conversely, bovine A/H5N1 NA binding and neuraminidase-inhibiting antibody responses were comparable to those against a human A/ H1N1 NA at baseline. Seasonal influenza vaccination failed to significantly increase antibody titers against both HA and NA glycoproteins of bovine A/H5N1. Recent infection with human A/H1N1 but not A/H3N2 viruses induced significant increases in bovine A/H5N1 n...

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

  By Scott Wieman - Own work, CC BY-SA 3.0,  https://commons.wikimedia.org/w/index.php?curid=24620634 A wild Herring Gull in Nordland Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6621 ____

#Russia - #Influenza A #H5 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

Di dierat-stock - Crow-1, CC BY 3.0,  https://commons.wikimedia.org/w/index.php?curid=33155653 A wild Carrion Crow in Khabarovsk Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6622 ____

The #impact of highly pathogenic avian #influenza #H5N1 virus infection on dairy #cows

Abstract Highly pathogenic avian influenza (HPAI) H5N1 virus has been associated with severe mastitis in dairy cows , leading to decreased milk production . Here we investigated the impact of H5N1 virus infection in health and production parameters in an affected dairy herd in Ohio . Clinical disease , which lasted for about three weeks , was recorded in 20.0% (777/3876) of the adult cows. Milk losses of ~900 kg per cow were recorded in affected cows during a 60 day-post-outbreak period . Seroprevalence was 89.4% (570/637) in the herd, with 76.1% (485/637) of seropositive animals being subclinically infected . Clinically affected cows presented an increased risk of death (6 times) and of premature herd removal (3.6 times) when compared to non-clinical cows. Economic losses due to decreased milk production, mortality, and early herd removal were estimated at $950 per clinically affected cow for a total cost of ~$737,500 for the herd during the observation period. Our results demonstrate...

#Surveillance and follow up #outcomes of #myocarditis after #mRNA #COVID19 #vaccination in #Australia

Abstract Clinical progression and medium-long term morbidity from myocarditis following mRNA COVID-19 vaccinations remains an important but undefined public health concern . We conducted prospective follow-up of individuals with either confirmed or probable myocarditis following monovalent Pfizer-BioNTech BNT162b2 or Moderna mRNA-1273 vaccination between 21 April 2021 and 5 July 2022 in Australia . Of 256 individuals who consented to follow up, mostly males following a second dose, 60% (133/221) had ongoing symptoms at 3-6 months and 35% (81/231) at 12-18 months. Self-reported ongoing exercise restrictions, medication requirements, and hospital re-presentations were associated with ongoing symptoms, as was a lower self-reported health status and quality of life. Clinical severity remained mild , with low hospitalisation rates and no deaths in the follow-up period and health-related quality of life improved over time. These findings support ongoing use of mRNA COVID-19 vaccines in at-ri...