Background/objectives: The safety and immunogenicity of the BNT162b2 coronavirus disease 2019 (COVID-19) vaccine in older adults with different frailty and disability profiles have not been well determined. Our objective was to analyze immunogenicity of the BNT162b2 mRNA COVID-19 vaccine in older adults across frailty and disability profiles.

Design: Multicenter longitudinal cohort study.

Setting and participants: A total of 134 residents aged ≥65 years with different frailty and disability profiles in five long-term care facilities (LTCFs) in Albacete, Spain. INTERVENTION AND

Measurements: Residents were administered two vaccine doses as per the label, and antibody levels were determined 21.9 days (SD 9.3) after both the first and second dose. Functional variables were assessed using activities of daily living (Barthel Index), and frailty status was determined with the FRAIL instrument. Cognitive status and comorbidity were also evaluated.

Results: Mean age was 82.9 years (range 65-99), and 71.6% were female. The mean antibody titers in residents with and without previous COVID-19 infection were 49,878 AU/ml and 15,274 AU/ml, respectively (mean difference 34,604; 95% confidence interval [CI]: 27,699-41,509). No severe adverse reactions were observed, after either vaccine dose. Those with prevaccination COVID-19 had an increased antibody level after the vaccine (B = 31,337; 95% CI: 22,725-39,950; p < 0.001). Frailty, disability, older age, sex, cognitive impairment, or comorbidities were not associated with different antibody titers.

Conclusions: The BNT162b2 mRNA COVID-19 vaccine in older adults is safe and produces immunogenicity, independently of the frailty and disability profiles. Older adults in LTCFs should receive a COVID-19 vaccine.