Molecular analysis of influenza A(H3N2) in a remote tropical island during 2014-2019 to identify the frequency of introduction and local circulation.

Background: The sources of new antigenic Influenza A(H3N2) variants and the role of tropical regions in the global A(H3N2) circulation remain unclear. By conducting molecular analysis, this study aimed to identify A(H3N2) introduction events and the duration of local circulation in a geographically remote tropical island.

Methods: Nasopharyngeal/nasal samples were collected from symptomatic children under five years old in a remote tropical island of the Philippines between 2014-2019.