Community seroprevalence and risk factors for SARS-CoV-2 infection in different subpopulations in Vellore, India, and their implications for future prevention. (March 2022)

• Record Type: Journal Article
• Authors: Dayanand, Divya; Irudhayanathan, Indhuja; Kundu, Debasree; Manesh, Abi; Abraham, Vinod; Abhilash, Kundavaram PP; Chacko, Binila; Moorthy, Mahesh; Samuel, Prasanna; Peerawaranun, Pimnara; Mukaka, Mavuto; Joseph, Jayaraj; Sivaprakasam, Mohanasankar; Varghese, George M
• Is Part Of: International journal of infectious diseases. Volume 116(2022)
• Page Start: 138
• Page End: 146
• Publication Date: 2022-03
• Subjects: Seroprevalence -- SARS-CoV-2 -- COVID -- India; Communicable diseases -- Periodicals; Communicable Diseases -- Periodicals; Communicable diseases; Periodicals; Electronic journals; 616.9
• DOI: 10.1016/j.ijid.2021.12.356
• Languages: English
• ISSNs: 1201-9712

Abstract

Highlights: The seroprevalence of SARS-CoV-2 in Vellore, India had reached over 70% by July 2021 Seroprevalence varied according to subpopulation, with the highest levels found in urban slums The vast majority of the infections (75%) were asymptomatic Vaccine uptake among urban slums and the rural population was poor A targeted vaccination for high-risk individuals is suggested Abstract: Objectives: The 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. Methods: The 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. Results: For 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. Conclusion: Although 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.