biostudies-literatureStuart ASVNational Institute for Health Research (NIHR)Wellcome TrustAcademy of Medical Sciences36-49https://www.ebi.ac.uk/biostudies/studies/S-EPMC8648333biostudies-literatureUnknown399(10319)<h4>Background</h4>Given the importance of flexible use of different COVID-19 vaccines within the same schedule to facilitate rapid deployment, we studied mixed priming schedules incorporating an adenoviral-vectored vaccine (ChAdOx1 nCoV-19 [ChAd], AstraZeneca), two mRNA vaccines (BNT162b2 [BNT], Pfizer-BioNTech, and mRNA-1273 [m1273], Moderna) and a nanoparticle vaccine containing SARS-CoV-2 spike glycoprotein and Matrix-M adjuvant (NVX-CoV2373 [NVX], Novavax).<h4>Methods</h4>Com-COV2 is a single-blind, randomised, non-inferiority trial in which adults aged 50 years and older, previously immunised with a single dose of ChAd or BNT in the community, were randomly assigned (in random blocks of three and six) within these cohorts in a 1:1:1 ratio to receive a second dose intramuscularly (8-1Lancet (London, England)Immunogenicity, safety, and reactogenicity of heterologous COVID-19 primary vaccination incorporating mRNA, viral-vector, and protein-adjuvant vaccines in the UK (Com-COV2): a single-blind, randomised, phase 2, non-inferiority trial.PMC8648333211153/Z/18/ZCL-2013-01-003NIHR201409NF-SI-0617-10010NIHR202437AMS-SGCL11-DuncanGreenland MFerreira DMNguyen-Van-Tam JSRamsay MRead RCMujadidi YFTurner PJCameron JCHeath PTLillie PJWhite RLiu XCharlton SSnape MDClutterbuck EASingh NLazarus RDarton THorsington BMHallis BPlested ELDuncan CJADinesh TCollins AMHill HEngland AStuart ASVShaw RHRobinson HLambe TPayne RCom-COV2 Study GroupFinn ATurner DPJGoodman ALScreaton GRGreen CARamasamy MNAndrews NJLibri VVichos IProvstgaard-Morys SAley PKFaust SNfalseImmunogenicity, safety, and reactogenicity of heterologous COVID-19 primary vaccination incorporating mRNA, viral-vector, and protein-adjuvant vaccines in the UK (Com-COV2): a single-blind, randomised, phase 2, non-inferiority trial.<h4>Background</h4>Given the importance of flexible use of different COVID-19 vaccines within the same schedule to facilitate rapid deployment, we studied mixed priming schedules incorporating an adenoviral-vectored vaccine (ChAdOx1 nCoV-19 [ChAd], AstraZeneca), two mRNA vaccines (BNT162b2 [BNT], Pfizer-BioNTech, and mRNA-1273 [m1273], Moderna) and a nanoparticle vaccine containing SARS-CoV-2 spike glycoprotein and Matrix-M adjuvant (NVX-CoV2373 [NVX], Novavax).<h4>Methods</h4>Com-COV2 is a single-blind, randomised, non-inferiority trial in which adults aged 50 years and older, previously immunised with a single dose of ChAd or BNT in the community, were randomly assigned (in random blocks of three and six) within these cohorts in a 1:1:1 ratio to receive a second dose intramuscularly (8-12022-01-01T00:00:00Z2022 Jan2025-04-19T10:42:55.248Z2022-02-11T15:06:17.075ZS-EPMC86483333488305310.1016/S0140-6736(21)02718-510.1016/s0140-6736(21)02718-5