Previous SARS-CoV-2 Infection, Age, and Frailty Are Associated With 6-Month Vaccine-Induced Anti-Spike Antibody Titer in Nursing Home Residents.
J Am Med Dir Assoc
; 23(3): 434-439, 2022 03.
Article
in English
| MEDLINE | ID: covidwho-1616555
ABSTRACT
OBJECTIVES:
Older nursing home residents make up the population at greatest risk of morbidity and mortality from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. No studies have examined the determinants of long-term antibody responses post vaccination in this group.DESIGN:
Longitudinal cohort study. SETTING ANDPARTICIPANTS:
Residents from 5 nursing homes assessed before vaccination, and 5 weeks and 6 months post vaccination, with the BNT162b2 messenger RNA SARS-CoV-2 vaccine.METHODS:
Comprehensive clinical assessment was performed, including assessment for comorbidity, frailty, and SARS-CoV-2 infection history. Serum nucleocapsid and anti-spike receptor binding domain (RBD) antibodies were analyzed at all timepoints. An in vitro angiotensin-converting enzyme (ACE2) receptor-spike RBD neutralization assay assessed serum neutralization capacity.RESULTS:
Of 86 participants (81.1 ± 10.8 years; 65% female), just under half (45.4%; 39 of 86) had evidence of previous SARS-CoV-2 infection. All participants demonstrated a significant antibody response to vaccination at 5 weeks and a significant decline in this response by 6 months. SARS-CoV-2 infection history was the strongest predictor of antibody titer (log-transformed) at both 5 weeks [ß 3.00; 95% confidence interval (CI) 2.32-3.70; P < .001] and 6 months (ß 3.59; 95% CI 2.89-4.28; P < .001). Independent of SARS-CoV-2 infection history, both age in years (ß -0.05; 95% CI -0.08 to -0.02; P < .001) and frailty (ß -0.22; 95% CI -0.33 to -0.11; P < .001) were associated with a significantly lower antibody titer at 6 months. Anti-spike antibody titers at both 5 weeks and 6 months significantly correlated with in vitro neutralization capacity. CONCLUSIONS AND IMPLICATIONS In older nursing home residents, SARS-CoV-2 infection history was the strongest predictor of anti-spike antibody titers at 6 months, whereas age and frailty were independently associated with lower titers at 6 months. Antibody titers significantly correlated with in vitro neutralization capacity. Although older SARS-CoV-2 naïve nursing home residents may be particularly vulnerable to breakthrough SARS-CoV-2 infection, the relationship between antibody titers, SARS-CoV-2 infection, and clinical outcomes remains to be fully elucidated in this vulnerable population.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Age Factors
/
Frailty
/
COVID-19
/
BNT162 Vaccine
/
Antibodies, Viral
Type of study:
Cohort study
/
Observational study
/
Prognostic study
Topics:
Vaccines
Limits:
Aged
/
Female
/
Humans
/
Male
Language:
English
Journal:
J Am Med Dir Assoc
Journal subject:
History of Medicine
/
Medicine
Year:
2022
Document Type:
Article
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