Despite “great advances in our ability to follow influenza occurrence and determine vaccine effectiveness (VE)” during the 2010–2020 decade, outcomes remain suboptimal for influenza vaccines, conclude authors of a review article. The decade had a pair of pandemic bookends: the 2009–2010 influenza pandemic and the start of the SARS-CoV-2 pandemic in 2020. During this time, advances in tracking influenza and measuring VE were “largely based on the widespread use of the polymerase chain reaction assay,” they note.
Focusing primarily on U.S. data and inactivated vaccines, the writers found the following: “Surveillance has expanded, resulting in increased ability to characterize circulating viruses and their impact. The surveillance has often confirmed previous observations on timing of outbreaks and age groups affected, which can now be examined in greater detail. Selection of strains for vaccines is now based on enhanced viral characterization using immunologic, virologic, and computational techniques not previously available. Vaccine coverage has been largely stable, but VE has remained modest and, in some years, very low. We discuss ways to improve VE based on existing technology while we work toward supraseasonal vaccines.”