Seroprevalence of SARS-CoV-2 specific IgG antibodies in District Srinagar, northern India – A cross-sectional study
Muhammad Salim Khan, Mariya Amin Qurieshi, Inaamul Haq, Sabhiya Majid, Arif Akbar Bhat, Sahila Nabi, Nisar Ahmad Ganai, Nazia Zahoor, Auqfeen Nisar, Iqra Nisar Chowdri, Tanzeela Bashir Qazi, Rafiya Kousar, Abdul Aziz Lone, Iram Sabah, Shahroz Nabi, Ishtiyaq Ahmad Sumji, Misbah Ferooz Kawoosa, Shifana Ayoub
Abstract
BACKGROUND: Prevalence of IgG antibodies against SARS-CoV-2 infection provides essential information for deciding disease prevention and mitigation measures. We estimate the seroprevalence of SARS-CoV-2 specific IgG antibodies in District Srinagar. METHODS: 2906 persons >18 years of age selected from hospital visitors across District Srinagar participated in the study. We tested samples for the presence of SARS-CoV-2 specific IgG antibodies using a chemiluminescent microparticle immunoassay-based serologic test. RESULTS: Age- and gender-standardized seroprevalence was 3.6% (95% CI 2.9% to 4.3%). Age 30-69 years, a recent history of symptoms of an influenza-like-illness, and a history of being placed under quarantine were significantly related to higher odds of the presence of SARS-CoV-2 specific IgG antibodies. The estimated number of SARS-CoV-2 infections during the two weeks preceding the study, adjusted for test performance, was 32602 with an estimated (median) infection-to-known-case ratio of 46 (95% CI 36 to 57). CONCLUSIONS: The seroprevalence of SARS-CoV-2 specific IgG antibodies is low in the District. A large proportion of the population is still susceptible to the infection. A sizeable number of infections remain undetected, and a substantial proportion of people with symptoms compatible with COVID-19 are not tested.