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Antibody Decline Among Older Adults in LTC After Second Dose of COVID-19 Vaccine
The Journal of the American Geriatrics Society recently released a multicenter longitudinal cohort study that explored antibody titer loss in older adults in long-term care facilities (LTCs) following the second dose of the BNT162b2 (BioNTech, Pfizer) COVID-19 vaccine.
According to authors of the study, this trial focused on 127 residents in 2 LTC facilities located in Albacete, Spain, which included 90 women and 37 men with the mean age of 82.7 years who had different frailty and disability profiles.
“Residents received 2 doses of BNT162b2 as per label, and antibody levels were determined 1 and 6 months after the second dose,” stated authors of the study. “Age, sex, previous history of COVID-19, comorbidity (Charlson index), performance in activities of daily living (Barthel index), frailty (FRAIL instrument), and cognitive status were assessed.”
Results of the study showed that the median antibody titer loss measured 77.6% (IQR 23.8%) across all participants.
“Notably, the decline of titers in individuals with pre-vaccination COVID-19 infection was significantly lower than in those without history of SARS-CoV-2 infection (72.2% vs 85.3%; P<.001),” stated authors of the study. “The median titer decrease per follow-up day was 0.47% (IQR 0.14%) and only pre-vaccination COVID-19 was associated with lower rate of antibody decline at 6 months (HR 0.17; 95% CI 0.07-0.41; P<.001).”
Results of the study also showed that the extent of antibody loss was not associated with frailty, disability, older age, cognitive impairment and comorbidity, according to authors.
“Older adults in LTC [facilities] experience a rapid loss of antibodies between over the first six months after the second dose of BNT162b2 vaccine,” concluded authors of the study. “Only pre-vaccination COVID-19 is associated with a slower rate of antibodies decrease. Our data support immunization with a third dose in this vulnerable, high-risk population.”
Reference:
Ríos SS, Zamora EBC, Céspedes AA, et al. Immunogenicity after six months of BNT162b2 vaccination in frail or disabled nursing home residents: the COVID-A Study. J Am Geriatr Soc. 2021. doi:10.1111/jgs.17620.
