biostudies-literatureBoikos CSeqirus (United States)Seqirus896https://www.ebi.ac.uk/biostudies/studies/S-EPMC9228909biostudies-literatureUnknown10(6)The adaptation of influenza seed viruses in egg culture can result in a variable antigenic vaccine match each season. The cell-based quadrivalent inactivated influenza vaccine (IIV4c) contains viruses grown in mammalian cell lines rather than eggs. IIV4c is not subject to egg-adaptive changes and therefore may offer improved protection relative to egg-based vaccines, depending on the degree of match with circulating influenza viruses. We summarize the relative vaccine effectiveness (rVE) of IIV4c versus egg-based quadrivalent influenza vaccines (IIV4e) to prevent influenza-related medical encounters (IRMEs) from three retrospective observational cohort studies conducted during the 2017-2018, 2018-2019, and 2019-2020 US influenza seasons using the same underlying electronic medical record dVaccinesReview of Analyses Estimating Relative Vaccine Effectiveness of Cell-Based Quadrivalent Influenza Vaccine in Three Consecutive US Influenza Seasons.PMC9228909NABoikos CMolrine DOrtiz JRPuig-Barbera JMcGovern IHaag MfalseReview of Analyses Estimating Relative Vaccine Effectiveness of Cell-Based Quadrivalent Influenza Vaccine in Three Consecutive US Influenza Seasons.The adaptation of influenza seed viruses in egg culture can result in a variable antigenic vaccine match each season. The cell-based quadrivalent inactivated influenza vaccine (IIV4c) contains viruses grown in mammalian cell lines rather than eggs. IIV4c is not subject to egg-adaptive changes and therefore may offer improved protection relative to egg-based vaccines, depending on the degree of match with circulating influenza viruses. We summarize the relative vaccine effectiveness (rVE) of IIV4c versus egg-based quadrivalent influenza vaccines (IIV4e) to prevent influenza-related medical encounters (IRMEs) from three retrospective observational cohort studies conducted during the 2017-2018, 2018-2019, and 2019-2020 US influenza seasons using the same underlying electronic medical record d2022-01-01T00:00:00Z2022 Jun2025-04-19T17:38:05.941Z2025-04-19T17:38:05.941ZS-EPMC92289093574650410.3390/vaccines10060896