Data and evidence
Strain selection
Exact strain matching is not essential for public health benefit.
Evidence from recent seasons shows that vaccines targeting closely related variants have delivered similar real-world effectiveness, even when the specific targeted strain was no longer dominant by the time of peak circulation (Sharff et al., Vaccine 2025).
For example, vaccines targeting JN.1- and KP.2-lineage variants showed comparable protection, despite rapid changes in circulating strains during the season (Sharff et al., Vaccine 2025; Laniece Delaunay et al., 2025).
Broad, lineage-level vaccine updates that prioritise cross-protection, rather than precise strain matching, may therefore offer more robust and reliable population-level protection (Sharff et al., Vaccine 2025).