biostudies-literatureLewis NMNational Center for Advancing Translational SciencesNational Institute of Allergy and Infectious DiseasesNCATS NIH HHSNIAID NIH HHSNHLBI NIH HHSUS Centers for Disease Control and PreventionNational Institutes of HealthNIGMS NIH HHSNIH HHS1694-1700https://www.ebi.ac.uk/biostudies/studies/S-EPMC9113447biostudies-literatureUnknown225(10)Vaccine effectiveness (VE) against COVID-19 hospitalization was evaluated among immunocompetent adults (≥18 years) during March-August 2021 using a case-control design. Among 1669 hospitalized COVID-19 cases (11% fully vaccinated) and 1950 RT-PCR-negative controls (54% fully vaccinated), VE was 96% (95% confidence interval [CI], 93%-98%) among patients with no chronic medical conditions and 83% (95% CI, 76%-88%) among patients with ≥ 3 categories of conditions. VE was similar between those aged 18-64 years versus ≥65 years (P > .05). VE against severe COVID-19 was very high among adults without chronic conditions and lessened with increasing comorbidity burden.The Journal of infectious diseasesEffectiveness of mRNA Vaccines Against COVID-19 Hospitalization by Age and Chronic Medical Conditions Burden Among Immunocompetent US Adults, March-August 2021.PMC9113447UL1 TR002243K23 GM1296611K23AI137321K23 AI13732175D30121F00002T32 HL087738T32 GM135169K23 HL153584Douin DGhamande SAGordon AJThornton-Thompson SOuellette SGhamande SMurthy KBaughman AChang SYZepeski AMartin ETHuynh DCrider CDSeiler SPoynter BCaspers SVisweswaran ASettele NNaioti EABowers RBrown SMBeeram MSelf WHWomack KNCalhoun NWalter AKaniclides AKampe CHalasa NAnderson LAMcNeal TAGarner OChandrasekaran SMaldonado PNZouyed ZTruscon RHough CLDouin DJLauring ASHager DNArroliga ASibenaller ZZhu YChappell JDBriceno GThomas JGibbs KWVerani JRZayed MTenforde MWThomas LPaulson TCHart KWGershengorn HShapiro NIClark Files DMallow CClinansmith BQadir NDriver CPatel MMScharber TGrijalva CGHendrickson APeltan IDParks LTen Lohuis CCHerrick JHicks MMitchell MMcSpadden EJDe Souza LPrekker MEBurnham CAMcDonald DGinder AOlson LNassar PMohr NMExline MCGoff JRice TWSilverman EHink TSo PLewis NMSchrag SJKobayashi MFrankel TMills EWilson JGMcKillop AHubel KArter OGHenning DJArmbruster BShehu ATyler PKarow SLandreth LSteingrub JSKrol OCarricato MBabcock HMMares JSteinbock KAGilbert JErickson HLMcHenry RGinde AABrennan CMcNeal TRhoads JPBongu JCasey JDLevitt JPark DBusse LWIVY Network CollaboratorsMehkri OChambers IKwon JHJohnson JAshok KWallace MRothman REChen JTLindsell CJValesano ALRivas CNair RGaglani MKindle RJensen KPriest EStubblefield WBFong RKing JPerez CFitzsimmons WJBielak RValvano WDCass CGong MNHoffman EBlair MLaRose MShort LMohamed AKeipp Talbot HKhan AStanley NBlair CSmith MStout LKhan MJorgensen JDuggal ARobart EEttlinger JRoque JKozikowski LAAston VfalseEffectiveness of mRNA Vaccines Against COVID-19 Hospitalization by Age and Chronic Medical Conditions Burden Among Immunocompetent US Adults, March-August 2021.Vaccine effectiveness (VE) against COVID-19 hospitalization was evaluated among immunocompetent adults (≥18 years) during March-August 2021 using a case-control design. Among 1669 hospitalized COVID-19 cases (11% fully vaccinated) and 1950 RT-PCR-negative controls (54% fully vaccinated), VE was 96% (95% confidence interval [CI], 93%-98%) among patients with no chronic medical conditions and 83% (95% CI, 76%-88%) among patients with ≥ 3 categories of conditions. VE was similar between those aged 18-64 years versus ≥65 years (P > .05). VE against severe COVID-19 was very high among adults without chronic conditions and lessened with increasing comorbidity burden.2022-01-01T00:00:00Z2022 May2026-05-07T17:57:54.324Z2025-04-05T08:47:35.767ZS-EPMC91134473493211410.1093/infdis/jiab619