biostudies-literatureUnknown9(5)Imran MSeqirus Inc<h4>Background</h4>Age-related immunosenescence may impair the immune response to vaccination in older adults. Adjuvanted influenza vaccines are designed to overcome immune senescence in older adults. This study estimated the relative vaccine effectiveness (rVE) of MF59-adjuvanted trivalent inactivated influenza vaccine (aIIV3) vs egg-derived quadrivalent inactivated influenza vaccine (IIV4e) and high-dose trivalent inactivated influenza vaccine (HD-IIV3) in preventing influenza-related medical encounters in the 2019-2020 US season.<h4>Methods</h4>This retrospective cohort study used electronic medical records linked to pharmacy and medical claims data. The study population included adults age ≥65 years with a record of aIIV3, IIV4e, or HD-IIV3 vaccination. A doubly robust inverse probabilOpen forum infectious diseasesofac167https://www.ebi.ac.uk/biostudies/studies/S-EPMC9045943biostudies-literatureRelative Effectiveness of MF59 Adjuvanted Trivalent Influenza Vaccine vs Nonadjuvanted Vaccines During the 2019-2020 Influenza Season.PMC9045943Boikos CPuig-Barbera JOrtiz JRImran MMansi JABonafede MFischer LO'Brien DfalseRelative Effectiveness of MF59 Adjuvanted Trivalent Influenza Vaccine vs Nonadjuvanted Vaccines During the 2019-2020 Influenza Season.<h4>Background</h4>Age-related immunosenescence may impair the immune response to vaccination in older adults. Adjuvanted influenza vaccines are designed to overcome immune senescence in older adults. This study estimated the relative vaccine effectiveness (rVE) of MF59-adjuvanted trivalent inactivated influenza vaccine (aIIV3) vs egg-derived quadrivalent inactivated influenza vaccine (IIV4e) and high-dose trivalent inactivated influenza vaccine (HD-IIV3) in preventing influenza-related medical encounters in the 2019-2020 US season.<h4>Methods</h4>This retrospective cohort study used electronic medical records linked to pharmacy and medical claims data. The study population included adults age ≥65 years with a record of aIIV3, IIV4e, or HD-IIV3 vaccination. A doubly robust inverse probabil2022-01-01T00:00:00Z2022 May2025-04-04T07:34:57.733Z2025-04-04T07:34:57.733ZS-EPMC90459433549313110.1093/ofid/ofac167