Competent immune responses to SARS-CoV-2 variants in older adults following two doses of mRNA vaccination

Aging is associated with a reduced magnitude of primary immune responses to vaccination. mRNA-based SARS-CoV-2 vaccines have shown efficacy in older adults but virus variant escape is still unclear. Here we analyze humoral and cellular immunity against an early-pandemic viral isolate and compare that to the P.1 (Gamma) and B.1.617.2 (Delta) variants in two cohorts (55 age) of mRNA vaccine recipients. We further measure neutralizing antibody titers for B.1.617.1 (Kappa) and B.1.595, with the latter SARS-CoV-2 isolate bearing the spike mutation E484Q. Robust humoral immunity is measured following second vaccination, and older vaccinees manifest cellular immunity comparable to the adult group against early-pandemic SARS-CoV-2 and more recent variants. More specifically, the older cohort has lower neutralizing capacity at 7-14 days following the second dose but equilibrates with the younger cohort after 2-3 months. While long-term vaccination responses remain to be determined, our results implicate vaccine-induced protection in older adults against SARS-CoV-2 variants and inform thinking about boost vaccination. mRNA-based SARS-CoV-2 vaccines can induce protective immunity in older individuals, but whether they encompass new variants is not clear. Here the authors assess mRNA vaccine responses in both younger (<50) and older (>55) cohorts to find slightly delayed humoral and cellular immunity in the latter but, more importantly, reactivity to multiple variants. (I understand an eTOC summary is provided, but unfortunately it does not conform with our format.)

Automated summary

Aging is associated with reduced immune responses to vaccination, but mRNA-based vaccines can induce protective immunity in older individuals against SARS-CoV-2 variants. The immune response in older vaccine recipients is slightly delayed compared to younger individuals, but reaches comparable levels after 2-3 months.