An epidemic surge of influenza A(H3N2) virus at the end of the 2016-2017 season in Taiwan with an increased viral genetic heterogeneity

The data in this study indicate that antigenic drift is not the primary determinant of the epidemic wave at the end of the 2016-2017 season. The fitness changes in new variants, waning immunity and climatic changes are considered as possible contributors to the resurgence of the influenza A(H3N2) virus.