biostudies-literatureRouers AFDA HHSAgency for Science, Technology and ResearchU.S. Food and Drug Administratione28258https://www.ebi.ac.uk/biostudies/studies/S-EPMC9874655biostudies-literatureUnknown95(1)Waning antibody levels against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the emergence of variants of concern highlight the need for booster vaccinations. This is particularly important for the elderly population, who are at a higher risk of developing severe coronavirus disease 2019 (COVID-19) disease. While studies have shown increased antibody responses following booster vaccination, understanding the changes in T and B cell compartments induced by a third vaccine dose remains limited. We analyzed the humoral and cellular responses in subjects who received either a homologous messenger RNA(mRNA) booster vaccine (BNT162b2 + BNT162b2 + BNT162b2; ''BBB") or a heterologous mRNA booster vaccine (BNT162b2 + BNT162b2 + mRNA-1273; ''BBM") at Day 0 (prebooster), Day 7, andJournal of medical virologyEfficient recall of SARS-CoV-2 variant-reactive B cells and T responses in the elderly upon heterologous mRNA vaccines as boosters.PMC987465575F40120C00085Lye DCChia PYWong JXEWang CIRao SCOVID-19 Study GroupSalleh SNMLin RJHLee THBei WRen ECRouers ANeo VPoh XYWong NNg LFPYeo NKOng SWXTay MZNgoh EZXTeo JRenia LYoung BEMacary PALoh CYGoh YSHor PXTan YJQian XChang ZWLim CHuang YKam IKJTorres-Ruesta AFong SWfalseEfficient recall of SARS-CoV-2 variant-reactive B cells and T responses in the elderly upon heterologous mRNA vaccines as boosters.Waning antibody levels against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the emergence of variants of concern highlight the need for booster vaccinations. This is particularly important for the elderly population, who are at a higher risk of developing severe coronavirus disease 2019 (COVID-19) disease. While studies have shown increased antibody responses following booster vaccination, understanding the changes in T and B cell compartments induced by a third vaccine dose remains limited. We analyzed the humoral and cellular responses in subjects who received either a homologous messenger RNA(mRNA) booster vaccine (BNT162b2 + BNT162b2 + BNT162b2; ''BBB") or a heterologous mRNA booster vaccine (BNT162b2 + BNT162b2 + mRNA-1273; ''BBM") at Day 0 (prebooster), Day 7, and2023-01-01T00:00:00Z2023 Jan2026-05-29T05:32:47.323Z2025-04-05T20:21:06.031ZS-EPMC98746553630505210.1002/jmv.28258