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Vaccine Effectiveness Against All-Cause Death Varies According to Frailty Status in Veterans with SARS-CoV-2 Infection During the Delta Surge
24 Pages Posted: 18 Mar 2022
More...Abstract
Background: Recent studies have shown that COVID-19 vaccination is effective at preventing infection and death in older populations. However, it is unclear whether vaccination effectiveness is reduced among patients with frailty. We compared vaccine effectiveness against all-cause death after COVID-19 infection during the Delta surge according to patients’ frailty status.
Methods: In this cohort study, we used data from US Veterans Health Administration (VHA) COVID-19 Shared Data. We included veterans who tested positive for SARS-CoV-2 between July 25, 2021, and September 30, 2021. We retrieved data including socio-demographic characteristics, baseline diagnoses, frailty score, vaccination information, and examined all-cause death at 30 days and up to 6 months. The hazard ratio (HR) of vaccinated compared to the unvaccinated for all-cause death was estimated for robust, pre-frail, and frail patients; vaccine effectiveness was estimated as 1- HR.
Findings: We identified 57,784 veterans mean age 57.5(SD-16·7), 50642(87·6%) male, 40743(70·5%) white, 28497, 49·3% robust; 16737, 29·0% prefrail; and 12550, 21·7% frail. Over a median follow-up of 4·8 months (IQR=1·07) there were 3422 deaths (n=1055, 30·8% in the vaccinated and n=2367, 69·2% in the unvaccinated). The vaccine effectiveness against all-cause death was 76% (95%CI:71-80) in the robust group, 73% (95% CI: 69-77) in the prefrail but only 62% (95% CI: 58-66) in the frail group.
Interpretation Compared to non-frail (prefrail and robust), patients with frailty had lower levels of vaccination protection against all-cause death. Future studies investigating COVID vaccine effectiveness should incorporate frailty assessments and actively recruit older adults with frailty.
Funding Information: This study was supported Miami Geriatric Research Education and Clinical Center (GRECC) and was supported using resources and facilities of the VA Informatics and Computing Infrastructure (VINCI), VA HSR RES 13-457.
Declaration of Interests: JR holds a grant from Longeveron Inc and received consulting fee from Pfizer. MA reports grants from the Canadian Frailty Network, CIHR, Public Health Agency of Canada, Sanofi, Pfizer, Merck and GSK, and payments from Pfizer, Sanofi and Seqirus outside the submitted work. All other authors declare no competing interests.
Ethics Approval Statement: This study was approved by the Institutional Review Board at the Miami Veterans Affairs Healthcare System and was exempted from the requirement for informed consent because study data was anonymized and deidentified in the Shared Data Resource.
Keywords: Frailty, COVID-19, SAS-Cov-2, Vaccine Effectiveness, Delta variant
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