Speaker
Description
The seasonal influenza virus subtypes and lineages differ in their impact in different age groups. Influenza A(H3N2) viruses have been regarded as affecting the elderly particularly hard. Consistent with this, Norwegian virological surveillance has for many years shown that the A(H3N2) viruses have been disproportionately represented among elderly patients compared with other subtypes and lineages. However, in recent seasons we have seen a trend with less pronounced over-representation of elderly persons among H3N2 cases.
In late summer 2025, a new H3N2 antigenic drift variant, subclade K, emerged and spread rapidly, causing unusually early outbreaks in many northern hemisphere countries, including Norway where this variant was clearly predominant among characterised H3N2 viruses. The K variant harbours mutations at several antigenically important sites in the viral haemagglutinin, which may differentially affect immunity in older and younger population groups, given their distinct histories of exposure to previous H3N2 antigenic variants.
In the present study, we investigate whether the age profile of H3N2 subtyped cases during the variant K-dominated 2025/2026 season differs from the H3N2 age profile prior to the emergence of subclade K.
| Registration ID | INF26-73 |
|---|---|
| Professional status of the speaker | Senior Scientist |
| Junior scientist status | No, I am not a junior scientist. |
Author
Co-authors
External references
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