Recent studies have suggested that to reach immunity, immunocompetent SARS-CoV-2 seropositive adults may only require 1 dose rather than 2 doses of a messenger RNA vaccine, however, these studies did not include older adults. Older adults living in nursing homes are at higher risk for severe COVID-19, and the immune response to the vaccine may differ from that of younger, healthier adults.
In a recent study published in JAMA Network, 102 residents participated, 60 had no prior SARS-CoV-2 infection, 36 had a positive RT-PCR result and were seropositive for SARS-CoV-2 N-protein IgG in June 2020, and 6 had a positive RT-PCR results or were seropositive for SARS-CoV-2 N-protein IgG. Of the 36 residents who had a positive RT-PCR result and were seropositive for SARS-CoV-2 N-protein in June 2020, 26 remained seropositive in January-February 2021 (72.2).
Preliminary findings of this study suggest that a single dose of BNT162b2 vaccine may be sufficient to obtain a high level of S-protein IgG antibody in nursing home residents previously diagnosed with COVID-19 based on RT-PCR results. Again, researchers are doing a great job trying to figure out the secret to preventing the spread of COVID-19 as well as “reinfection”! Stay current, read everything you can and stay well!