Abstract
BACKGROUND: The clustering of metabolic abnormalities may weaken vaccine-induced immunity, but epidemiological data regarding SARS-CoV-2 vaccines are scarce. The present study aimed to examine the cross-sectional association between metabolic syndrome (MetS) and humoral immune response to Pfizer-BioNTech vaccine among the staff of a research center for medical care in Japan. METHODS: Participants were the staff (aged 21-75 years) of the National Center of Global Health and Medicine who had completed the second dose of Pfizer-BioNTech vaccine 1-3 months before the survey. MetS was defined according to the Joint Interim Statement. SARS-CoV-2 spike immunoglobulin G (IgG) antibody was measured using quantitative assays. Multivariable linear regression was used to estimate the geometric mean titers (GMT) and geometric mean ratio (GMR) of IgG titers, relative to MetS status. RESULTS: Of 946 participants who received the second vaccine dose, 51 (5.4%) had MetS. Those with MetS had a significantly lower IgG titer (GMT 4125; 95% confidence interval [CI], 2885-5896) than those without MetS (GMT 5348; 95% CI, 3914-7309); the GMR was 0.77 (95% CI 0.64-0.93). Taking those having no MetS component as reference, fully adjusted GMR (95% CI) for those having 1, 2, 3 or ≥ 4 components was 1.00 (0.90, 1.11), 0.89 (0.77, 1.04), 0.86 (0.68, 1.10) and 0.61 (0.45, 0.82), respectively (P trend = 0.024). CONCLUSION: Results suggest that having MetS and a greater number of its components are associated with a weaker humoral immune response to the Pfizer-BioNTech vaccine.