ETIDIOH - NEW

  Abstract As part of its role in the World Health Organization (WHO) Global Influenza Surveillance and Response System (GISRS), the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne received 12,180 human influenza-positive samples during 2024 . Viruses were analysed for their antigenic, genetic, and antiviral susceptibility properties . Selected viruses were propagated in qualified cells or embryonated hens’ eggs for potential use in seasonal influenza virus vaccines. During 2024 , influenza A( H1N1 )pdm09 and A( H3N2 ) viruses predominated , accounting for 33% and 42%, respectively, of all viruses received, compared to 5% for influenza B/Victoria . Of note, one influenza A(H5N1) virus was also received in 2024 . The majority of A(H1N1)pdm09 (98%), A(H3N2) (88%) and influenza B (100%) viruses analysed at the Centre were found to be antigenically and genetically similar to the respective WHO recommended vaccine strains for the Southern Hemisphere in 2024...

  Abstract Newly emerging influenza virus strains pose a constant threat as they encounter a population lacking neutralizing antibodies against the new strain . However, cross-reactive non-neutralizing antibodies (nnABs) may be present and assist in mitigating disease symptoms via various effector mechanisms, including antibody-dependent cellular cytotoxicity (ADCC). Although nnABs to influenza virus have received more attention lately , little information is available on their age-related prevalence , steady-state levels, functional properties , and changes in these parameters over time. Using longitudinal samples from adolescents, adults, and older adults , collected before and after the 2009 swine flu pandemic , we comprehensively characterized the specificity and functionality of nnAB responses against H1N1 pandemic 2009 (H1N1pdm09) virus . Remarkably, all participants exhibited cross-reactive antibodies to this virus before having encountered it through infection or vaccinatio...

  Abstract Background :  Genetic drift and host-associated adaptation in influenza A viruses threaten the long-term reliability of RT-qPCR-based diagnostics , particularly when nucleotide mismatches arise within primer and probe binding regions . Conventional assay evaluations often emphasize sequence conservation but rarely assess functional mismatch tolerance across divergent subtypes and hosts.  Methods :  We performed an in silico evaluation of a matrix (M) gene–targeted RT-qPCR assay by aligning primer and probe binding regions against 22 H1N1 isolates and representative H3N2 and H5N1 reference strains, including recent zoonotic isolates from avian and bovine hosts . Nucleotide mismatches were identified, quantified, and mapped relative to assay components and oligonucleotide termini. Mismatch burden was summarized by subtype and assay region.  Results :  H1N1 isolates exhibited complete conservation across primer and probe regions. In contrast, H3N2 a...