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ObjectivesThe aim of this study was to inform public health policy decisions through the assessment of IgG antibody seroprevalence in the population and the risk factors for SARS-CoV-2 infection.MethodsThe seroprevalence of IgG antibodies among different subpopulations at the end of the first and second waves of the pandemic was estimated. Various risk factors associated with seropositivity, including sociodemography, IgG antibodies against endemic human coronavirus, and vaccination status, were also assessed.ResultsFor all 2433 consenting participants, the overall estimated seroprevalences at the end of first and second waves were 28.5% (95% CI 22.3-33.7%) and 71.5% (95% CI 62.8-80.5%), respectively. The accrual of IgG positivity was heterogeneous, with the highest seroprevalences found in urban slum populations (75.1%). Vaccine uptake varied among the subpopulations, with low rates (< 10%) among rural and urban slum residents. The majority of seropositive individuals (75%) were asymptomatic. Residence in urban slums (OR 2.02, 95% CI 1.57-2.6; p < 0.001), middle socioeconomic status (OR 1.77, 95% CI 1.17-2.67; p = 0.007), presence of diabetes (OR 1.721, 95% CI 1.148-2.581; p = 0.009), and hypertension (OR 1.75, 95% CI 1.16-2.64; p = 0.008) were associated with seropositivity in multivariable analyses.ConclusionAlthough considerable population immunity has been reached, with more than two-thirds seropositive, improved vaccination strategies among unreached subpopulations and high-risk individuals are suggested for better preparedness in future.

Original publication

DOI

10.1016/j.ijid.2021.12.356

Type

Journal

International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases

Publication Date

03/2022

Volume

116

Pages

138 - 146

Addresses

Department of Infectious Diseases, Christian Medical College, Vellore, Tamil Nadu, India.

Keywords

Humans, Antibodies, Viral, Risk Factors, Seroepidemiologic Studies, India, COVID-19, SARS-CoV-2