Seroprevalence of COVID-19 in a City in India: A Community-based Cross-Sectional Study
Background: Population-based sero-epidemiological studies explain the extent of SARS-CoV-2 infection. This study was conducted in view of studying the seroprevalence in the second phase of pandemic in Nashik City of Maharashtra a state in western India. Maharashtra has the highest case fatality rate of 23.13%, hence it is necessary to study the extent of spread of infection to propose further management protocols until vaccine is made available to public. Objectives: To understand the current spread of infection in the community and thus imply the need for stringent preventive measures to be followed until the vaccine is made available to all. Methods: A Community based cross-sectional study was conducted in the six ‘Prabhags’ of Nashik Municipal Corporation. House to house survey was done from 9th to 11th of January 2021. Google forms were used for data collection and 3-5 ml of venous blood was collected after taking informed consent of the participant. The blood was transported for COVID-19 IgG antibody test by ELISA method at Viral Research and Diagnostics Laboratory, Nashik as per ICMR (Indian Council of Medical Research) guidelines. Results: Total Sero-prevalence of SARS-CoV-2 was 39.53% (CI: 37.55-41.54). A higher seropositivity rate 42.07% (CI: 39.07-46.39) was found in the slum areas (χ2=4.214; p=0.02). The Prabhag with highest seropositivity of 42.66% was New Nashik Cidco. Adding together the people who tested positive for SARS-CoV-2 antigen and those who tested positive for SARS-CoV-2 antibody, 42.29% (996 out of 2355) of population seems to be exposed to COVID-19 infection.