Cross-reactive #neuraminidase inhibition #antibodies against #H5N1 by consecutive #influenza A imprinting cohorts of the past century: population-based serosurvey, British Columbia, #Canada
Abstract Background : Avian influenza of the H5N1 subtype shares substantial relatedness in its neuraminidase (NA) surface protein with human influenza A H1N1 viruses of the past century. Understanding variation in pre-existing anti-N1 antibodies against H5N1 is critical to pandemic risk assessment and preparedness. Methods : We used anonymized, residual sera collected equally from ten age groups spanning one to >80 years during an August 2024 cross-sectional serosurvey in British Columbia, Canada . We assessed NA inhibition antibody titres by enzyme-linked lectin assay against H5N1 (N=575), H1N1pdm09 (N=250) and H3N2 (N=205). We compared anti-NA titres by birth (imprinting) cohorts defined in relation to historic N1 and/or N2 exposure opportunities. Results : Among participants with median age 32 (IQR: 15-62) years, 404 ( 70%) had cross-reactive anti-N1 titre ≥10 against H5N1 , with 260 (45%), 182 (32%) and 98 (17%), having titres ≥40, ≥80 and ≥...