Seroprevalence of SARS-CoV-2 specific IgG antibodies in District Srinagar, northern India - A cross-sectional study

PLoS One. 2020 Nov 11;15(11):e0239303. doi: 10.1371/journal.pone.0239303. eCollection 2020.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Antibodies, Viral / blood*
  • Betacoronavirus / genetics
  • Betacoronavirus / immunology*
  • Betacoronavirus / isolation & purification
  • COVID-19
  • Comorbidity
  • Coronavirus Infections / diagnosis*
  • Coronavirus Infections / epidemiology
  • Coronavirus Infections / virology
  • Cross-Sectional Studies
  • Female
  • Humans
  • Immunoglobulin G / blood*
  • India / epidemiology
  • Male
  • Middle Aged
  • Odds Ratio
  • Pandemics
  • Pneumonia, Viral / diagnosis*
  • Pneumonia, Viral / epidemiology
  • Pneumonia, Viral / virology
  • RNA, Viral / genetics
  • RNA, Viral / metabolism
  • SARS-CoV-2


  • Antibodies, Viral
  • Immunoglobulin G
  • RNA, Viral

Grants and funding

This work was supported by primarily Institutional funding with support from the District Disaster Management Authority, Srinagar.