Background Influenza vaccine effectiveness (VE) can vary by type and subtype. Over the
past decade, the test-negative design has emerged as a valid method for estimation of VE …

Introduction: Studies in the 1970s and 1980s signaled concern that repeated influenza
vaccination could affect vaccine protection. The antigenic distance hypothesis provided a …

Background Influenza vaccine effectiveness (VE) is generally interpreted in the context of
vaccine match/mismatch to circulating strains with evolutionary drift in the latter invoked to …

Background Influenza vaccines are most effective when the antigens in the vaccine match
those of circulating strains. However, antigens contained in the vaccines do not always …

Background Influenza vaccines require annual readministration; however, several reports
have suggested that repeated vaccination might attenuate the vaccine's effectiveness. We …

Background. Each year, the US Influenza Vaccine Effectiveness Network examines the
effectiveness of influenza vaccines in preventing medically attended acute respiratory …

Background: The test-negative design is an increasingly popular approach for estimating
vaccine effectiveness (VE) due to its efficiency. This review aims to examine published test …

Abstract Background. During the 2012–2013 influenza season, there was cocirculation of
influenza A (H3N2) and 2 influenza B lineage viruses in the United States. Methods. Patients …

Background: With the emergence and spread of new SARS-CoV-2 variants, concerns are
raised about the effectiveness of the existing vaccines to protect against these new variants …

The effect of prior influenza vaccination history on vaccine effectiveness was assessed in a
community cohort over 8 seasons. Current-and previous-season vaccination generated …