Researchers have highlighted the advantages of prior SARS-CoV-2 infection among older persons with decreased vaccination efficacy (VE) of COVID-19 immunizations in a study published in The Lancet Health Longevity.

About 500 staff members and residents over 65 years were included in the study. They received either the second dose of the BNT162b2 (BioNTech-Pfizer) or the ChAdOx1 nCoV-19 (Oxford-AstraZeneca) vaccines, and after the second COVID-19 vaccination, the titers of antibodies against the SARS-CoV-2 spike (S) protein were measured. Additionally, the impact of receiving a second COVID-19 vaccination on the neutralization of SARS-CoV-2 was assessed.

The second vaccination dramatically increased anti-S titers and improved SARS-CoV-2 neutralization among study participants who had never been exposed to COVID-19; previously seropositive residents who had antibody titers against the SARS-CoV-2 nucleocapsid (N) protein had titers that were comparable to those of the staff group. Importantly, both teams showed that SARS-CoV-2 neutralization was approximately 100% effective.

Overall, the study′s findings demonstrated that older and more fragile adults may produce anti-SARS-CoV-2 responses that were as potent and long-lasting as those produced by younger adults after COVID-19. To determine the extent to which older persons are immune protected against future SARS-CoV-2 variants by naturally occurring SARS-CoV-2 infections and to clarify the mechanisms of such immune protection, additional study is required. (News-medical.net, Jul 18 2022)