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  {Excerpt} (...) COVID-19 current vaccine safety status and insights   -- Since 2021, GACVS has regularly reviewed the safety of COVID-19 vaccines , including through global pharmacovigilance data and dedicated reviews of myocarditis, pregnancy outcomes and other adverse events of special interest (AESI).  -- The most recent updates reaffirmed that the benefits of vaccination outweigh the risks across all groups and advised continued monitoring for younger males and follow-up of persons who have reported vaccine-associated myocarditis .  -- Many individuals have received three or more doses of COVID-19 vaccine.  -- Some adverse events – such as myocarditis – seem to occur mainly after the second dose of mRNA COVID- 19 vaccines.  -- However, the outcomes were less severe in persons who developed myocarditis after vaccination compared to those unvaccinated and following infections, including SARS- CoV-2.  -- Also, children under six months of age seem t...

  Abstract The development of broadly protective and dose-sparing influenza vaccines remains a critical challenge , particularly for zoonotic H5N1 strains with pandemic potential . This study evaluates BECC470s, a synthetic TLR4 adjuvant , for its ability to enhance the immunogenicity and protective efficacy of recombinant H5 hemagglutinin (rHA) vaccination in murine models . BECC470s-adjuvanted rHA elicited robust IgG1/IgG2a antibody responses and complete survival following homologous 2004 H5N1 challenge in a prime–boost model . Although BECC470s broadened antibody binding to both variable HA head and conserved stalk domains by ELISA, functional neutralizing antibody responses were restricted to the matched 2004 H5N1 isolate, with no detectable neutralization of H5N1 viruses isolated in 2022 or 2024. These data indicate that BECC470s enhances the magnitude and apparent breadth of binding antibody responses while maintaining strain-specific neutralizing activity, supporting its po...

  Abstract Transmission of highly pathogenic avian influenza from H5 clade 2.3.4.4b has expanded in recent years to infect large populations of birds and mammals , heightening the risk of a human pandemic . Influenza viruses that are adapted to transmission in birds and a variety of mammals tend to have a less stable hemagglutinin (HA) than seasonal influenza viruses, enabling membrane fusion at comparatively higher pH levels . Here, we combined five mutations in the H5 HA that increased its melting temperature and promoted stable closure of the HA trimer . Structural analysis by cryo–electron microscopy revealed that the stabilizing mutations create several new hydrophobic interactions while maintaining the local HA structure . We found that vaccinating mice with stabilized H5 HA immunogens resulted in higher hemagglutination inhibition and neutralization titers than nonstabilized comparators. Epitope mapping of vaccine-elicited polyclonal antibody responses using negative-stain e...

  Abstract Highly pathogenic avian influenza (HPAI) clade 2.3.4.4b H5N1 virus has recently emerged in dairy cattle in the United States . The virus replicates primarily in the mammary gland of infected cattle, leading to dramatic reductions in milk production . It is thought that the virus transmits from animal to animal through viral shedding in milk , and therefore, vaccines that decrease the amount of virus in milk can potentially limit the current outbreak and reduce the risk of H5N1 spillover into humans . Here, we assess the immunogenicity and efficacy of a clade 2.3.4.4b H5 mRNA-LNP vaccine in lactating dairy cows . We found that the H5 mRNA-LNP vaccine elicited robust antibody responses in sera and milk and significantly reduced viral replication and disease caused by clade 2.3.4.4b H5N1 intramammary infection. Competing Interest Statement S.E.H. and D.W. are co-inventors on patents that describe the use of nucleoside-modified mRNA as a platform to deliver therapeutic prote...

  Abstract High pathogenicity avian influenza A(H5) viruses pose a pandemic threat . These viruses have rapidly evolved in birds and frequently crossed species barriers , resulting in over 1,000 confirmed human infections , with a case fatality proportion of approximately 50%. In response, the U.S. CDC has developed dozens of A(H5) candidate vaccine viruses (CVVs) over the past two decades, primarily targeting clades known to infect humans. This report summarizes the development and characterization of the CVVs, with a particular focus on their antigenic relationships with clades 2.3.2.1e and 2.3.4.4b A(H5N1) viruses , which have been responsible for the majority of recent human infections. Source:  Link:  https://academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiag132/8502029 ____

  February 2026  WHO convenes technical consultations {1} in February and September each year to recommend viruses for inclusion in influenza vaccines {2} for the northern hemisphere (NH) and southern hemisphere (SH) influenza seasons, respectively.  This recommendation relates to the influenza vaccines for use in the NH 2026-2027 influenza season .  A recommendation will be made in September 2026 relating to vaccines that will be used for the SH 2027 influenza season.  WHO guidance for choosing between the NH and SH formulations for countries in tropical and subtropical regions is available on the WHO Global Influenza Programme website {3}.   National or regional authorities approve the composition and formulation of influenza vaccines used in each country.  National public health authorities are responsible for making recommendations regarding the use of the vaccine.  WHO has published recommendations on the prevention of influenza {4}....

  Highlights •  Global Health Impact : Improved influenza vaccines have the potential to avert between 6.6 and 18 billion additional influenza cases, prevent 2.3 to 6.2 million additional deaths, and save 21 to 57 million disability-adjusted life years (DALYs) globally beyond those averted by current seasonal influenza vaccines •  Cost-Effectiveness : Depending on the price, coverage, and vaccine characteristics, improved influenza vaccines could be cost-effective in 9 to 48 % of countries, offering substantial global economic value under most scenarios •  Financial Viability : The development and commercialization of improved influenza vaccines present a robust financial value proposition, with positive net present value (NPV) across all vaccine profiles •  Policy and Decision Making : Vaccine efficacy, duration of protection, and breadth of protection are key factors influencing the adoption of improved influenza vaccines in national immunization programs •...

  Abstract Background   Seasonal human influenza viruses can escape from antibody-mediated neutralization when amino acid changes occur in the hemagglutinin protein . Routine surveillance identified circulation of an A(H3N2) virus variant in the Netherlands with amino acid substitutions at hemagglutinin positions 158 and 189 . These amino acid positions were previously responsible for antigenic change of influenza A(H3N2) viruses and potentially lead to escape of this variant from vaccine-mediated immunity .  Aim   To characterize the emergence and antigenic properties of N158K and K189R double substitution virus variants .  Methods   We analyzed the geographical and temporal dynamics of the double-substitution variant using a phylogeographic approach and used hemagglutination inhibition assays and antigenic cartography methods to map its antigenic properties.  Results   A(H3N2) viruses carrying K189R were first detected in Guatemala in June 2024,...

  {Summary} In summer 2025, the SARS-CoV-2 JN.1 sublineage became dominant with more resistant variants, such as XFG, LP.8.1, and NB.1.8.1 . COVID-19 mRNA boosters were therefore updated for the 2025–2026 season to target the LP.8.1 spike .1 Previous boosters, particularly the WA1/2020+BA.5 bivalent booster , were characterised by substantial boosting of the ancestral strain , a phenomenon known as immune imprinting .2,3 We therefore evaluated whether the phylogenetically more distant LP.8.1 mRNA booster would preferentially boost currently circulating strains. Recent data from European and Asian populations have reported the immunogenicity of the LP.8.1 mRNA booster .4,5 Herein, we report the immunogenicity of the LP.8.1 mRNA booster in a US population with a different exposure history and high population immunity. We show that the LP.8.1 mRNA booster induced neutralising antibody (NAb) and binding antibody responses, primarily to the vaccine-matched L.P.8.1 variant and other curr...

  Highlights •  Randomized trial of 1st and 2nd mRNA SARS-CoV-2 booster vaccination in advanced age •  Higher anti-RBD IgG level and neutralizing capacity with full-dose mRNA-1273 than BNT162b2 •  Decrease in viral neutralization capacity after 12 months against all 25 tested SARS-COV-2 variants •  Oldest population in a SARS-CoV-2 vaccination study (mean 81 yrs) ABSTRACT Background To determine long-term immunogenicity and reactogenicity of different SARS-CoV-2 mRNA-vaccines in a population ≥75 years in a randomized trial. Methods Participants were randomised to receive either BNT162b2 30µg or double booster dose mRNA-1273 , i.e.100µg, as 3rd and 4th vaccination (1st and 2nd booster). Primary endpoint was rate of 2-fold geometric mean titre (GMT) antibody increase 14 days after vaccination targeting the receptor binding domain (RBD) region of wild-type SARS-CoV-2. Secondary endpoints included neutralising capacity against wild-type and 25 variants at 14 days (D...

  Abstract Middle East respiratory syndrome coronavirus (MERS-CoV) was identified as a human pathogen in 2012 and causes ongoing sporadic infections and outbreak clusters . Despite case fatality rates (CFRs) of over 30% and considerable pandemic potential , a safe and efficacious vaccine has not been developed. Here we report the design, characterization, and preclinical evaluation of MERS-CoV antigens . Our lead candidate comprises a stabilized spike displayed on a self-assembling ferritin nanoparticle that can be produced from a high-expressing, stable cell pool . This vaccine elicits robust MERS-CoV pseudovirus and authentic virus neutralizing antibody titers in BALB/c mice. Immunization of male non-human primates (NHPs) with one dose of Alhydrogel-adjuvanted vaccine elicited a > 103 geometric mean titer of pseudovirus neutralizing antibodies that was boosted with a second dose. Sera from these NHPs exhibited cross-reactivity against spike-pseudotyped lentiviruses from MERS-C...

  Abstract Introduction Seasonal influenza causes significant global morbidity, mortality, and economic burden . Ongoing viral evolution can lead to vaccine mismatch and the emergence of antiviral resistance , highlighting the importance of genomic surveillance. The 2024–2025 influenza season was characterized by high incidence and increased hospitalizations. Methods We analyzed influenza A virus (IAV) genomes and clinical characteristics from the 2024–2025 season . Whole-genome sequencing was performed on 648 influenza A–positive clinical specimens collected between October 2024 and April 2025. Results Hemagglutinin (HA) sequences were recovered from 74.23% (481/648) of samples and used for subtyping and phylogenetic analysis. A(H1N1)pdm09 and A(H3N2) viruses co-circulated , representing 55.5% and 44.5% of cases, respectively. Among A(H1N1)pdm09 viruses, the HA1 substitution T120A , located near the Sa antigenic site , increased more than twofold compared with the prior season. Ci...

  Abstract Highly pathogenic avian influenza H5N1 virus has spread to over 1,080 dairy farms across 18 states in the United States, resulting in 41 human infections and posing serious risks to both animal and public health . To address these risks, a hemagglutinin-based mRNA–lipid nanoparticle vaccine was developed , and its safety, immunogenicity, and protective efficacy in high-yielding lactating dairy cows were evaluated. The vaccine was well tolerated, had no adverse effects on health or milk production , and induced strong antibody responses . Two weeks after the second immunization, all the immunized cattle were fully protected against a high-dose H5N1 virus challenge . Notably, two-thirds of the cattle were still completely protected even at the 19th week after the first vaccination , when their serum antibody levels were very low. These data demonstrate that the mRNA vaccine confers robust, lasting protection against H5N1 virus in lactating dairy cows, providing a foundatio...

  {Summary} Recent headlines about influenza have reported a “super flu” causing a “record-breaking season” that is “overwhelming hospitals.” Although less dramatic, data from the Centers for Disease Control and Prevention (CDC) reveal substantial influenza activity : the agency estimated that there were more than 20 million cases of influenza illness, 270,000 influenza-related hospitalizations , and 11,000 deaths from influenza in the United States through January 24, 2026. These numbers aren’t extraordinary as compared with those from previous seasons, but some indicators of influenza activity and severity have been remarkable. (...) Source:  Link:  https://www.nejm.org/doi/full/10.1056/NEJMp2600395?query=TOC ____

  Highlights •  IN-delivered ChAd-Texas vaccine elicits mucosal antibody and T cell responses •  IN-delivered ChAd-Texas vaccine protects against H5N1 in mice and hamsters •  IN delivery of ChAd-Texas vaccine confers greater protection than IM delivery •  ChAd-Texas induces H5N1 immunity in the setting of prior influenza immunity Summary The emergence of highly pathogenic avian H5N1 influenza viruses in dairy cows and humans has increased the potential for another pandemic . To address this risk, we developed chimpanzee adenoviral (ChAd)-vectored H5 hemagglutinin-targeted vaccines and tested their immunogenicity and efficacy in rodents . Immunization with ChAd-Texas (clade 2.3.4.4b) vaccine in mice elicits neutralizing antibody responses and confers protection against viral infection and mortality upon challenge with a human H5N1 isolate (A/Michigan/90/2024, clade 2.3.4.4b). Intranasal delivery of the ChAd-Texas vaccine elicits mucosal antibody and T cell respon...