Seroconversion and side effects after COVID vaccination among persons with type 2 diabetes in urban, rural, and tribal areas in Kerala, India

Abstract

Background: Persons with type 2 diabetes mellitus (T2DM) are at high-risk for COVID-19 infection and are a priority group for vaccination. Objectives: The objective of this study is to estimate the seroconversion and determine the side effects after COVID-19 vaccination among persons with T2DM in urban, rural, and tribal areas in Kerala. Methods: A cross-sectional study was conducted in urban, rural, and tribal field practice areas of a medical college in Central Kerala, among 396 persons with T2DM. The participants were selected by simple random sampling from the 200–250 diabetic patients visiting each health center. Qualitative and quantitative estimation of antibodies were done by WANTAI Ab enzyme-linked immunosorbent assay kit and Abbott SARS COV-2 IgG Quantitative assay, respectively. Results: The mean age of the respondents was 59.40 ± 12.25 years. A majority (65.5%) had received both doses of vaccine. About half (51.5%) experienced side effects after vaccination. Antibodies (IgG or IgM) were detected in 93.2% (95% confidence interval [CI] 90.2, 95.5) of participants. Those with a duration of diabetes ≥5 years, with a single dose of vaccine, were five times (adjusted odds ratio [aOR] – 5.23,95% CI 1.86, 14.66) and four times (aOR – 4.11, 95% CI 1.66, 10.13) more likely, respectively, to be seronegative. Those who took medication for diabetes were protected against a no antibody (aOR – 0.05, 95% CI 0.02, 0.148) response. The median antibody titer in a subset (150) of participants was 365.2 (90–1587) AU/ml. Past COVID infection was an independent determinant of high IgG titers (aOR – 4.95, 95% CI 1.50, 16.36). Conclusion: Reinforcing the importance of vaccination particularly among those with longer duration of diabetes is imperative.

Keywords

• covid-19
• seroconversion
• type 2 diabetes mellitus
• covid vaccine
• antibody titer