{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T07:38:56Z","timestamp":1790753936374,"version":"4.1.0"},"update-to":[{"DOI":"10.1371\/journal.pmed.1003877","type":"new_version","label":"New version","source":"publisher","updated":{"date-parts":[[2022,1,4]],"date-time":"2022-01-04T00:00:00Z","timestamp":1641254400000}}],"reference-count":26,"publisher":"Public Library of Science (PLoS)","issue":"12","license":[{"start":{"date-parts":[[2021,12,10]],"date-time":"2021-12-10T00:00:00Z","timestamp":1639094400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001411","name":"Indian Council of Medical Research","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001411","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosmedicine.org"],"crossmark-restriction":false},"short-container-title":["PLoS Med"],"abstract":"<jats:sec id=\"sec001\">\n<jats:title>Background<\/jats:title>\n<jats:p>India began COVID-19 vaccination in January 2021, initially targeting healthcare and frontline workers. The vaccination strategy was expanded in a phased manner and currently covers all individuals aged 18 years and above. India experienced a severe second wave of COVID-19 during March\u2013June 2021. We conducted a fourth nationwide serosurvey to estimate prevalence of SARS-CoV-2 antibodies in the general population aged \u22656 years and healthcare workers (HCWs).<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec002\">\n<jats:title>Methods and findings<\/jats:title>\n<jats:p>We did a cross-sectional study between 14 June and 6 July 2021 in the same 70 districts across 20 states and 1 union territory where 3 previous rounds of serosurveys were conducted. From each district, 10 clusters (villages in rural areas and wards in urban areas) were selected by the probability proportional to population size method. From each district, a minimum of 400 individuals aged \u22656 years from the general population (40 individuals from each cluster) and 100 HCWs from the district public health facilities were included. The serum samples were tested for the presence of IgG antibodies against S1-RBD and nucleocapsid protein of SARS-CoV-2 using chemiluminescence immunoassay. We estimated the weighted and test-adjusted seroprevalence of IgG antibodies against SARS-CoV-2, along with 95% CIs, based on the presence of antibodies to S1-RBD and\/or nucleocapsid protein. Of the 28,975 individuals who participated in the survey, 2,892 (10%) were aged 6\u20139 years, 5,798 (20%) were aged 10\u201317 years, and 20,285 (70%) were aged \u226518 years; 15,160 (52.3%) participants were female, and 21,794 (75.2%) resided in rural areas. The weighted and test-adjusted prevalence of IgG antibodies against S1-RBD and\/or nucleocapsid protein among the general population aged \u22656 years was 67.6% (95% CI 66.4% to 68.7%). Seroprevalence increased with age (<jats:italic>p &lt;<\/jats:italic> 0.001) and was not different in rural and urban areas (<jats:italic>p =<\/jats:italic> 0.822). Compared to unvaccinated adults (62.3%, 95% CI 60.9% to 63.7%), seroprevalence was significantly higher among individuals who had received 1 vaccine dose (81.0%, 95% CI 79.6% to 82.3%, <jats:italic>p &lt;<\/jats:italic> 0.001) and 2 vaccine doses (89.8%, 95% CI 88.4% to 91.1%, <jats:italic>p &lt;<\/jats:italic> 0.001). The seroprevalence of IgG antibodies among 7,252 HCWs was 85.2% (95% CI 83.5% to 86.7%). Important limitations of the study include the survey design, which was aimed to estimate seroprevalence at the national level and not at a sub-national level, and the non-participation of 19% of eligible individuals in the survey.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec003\">\n<jats:title>Conclusions<\/jats:title>\n<jats:p>Nearly two-thirds of individuals aged \u22656 years from the general population and 85% of HCWs had antibodies against SARS-CoV-2 by June\u2013July 2021 in India. As one-third of the population is still seronegative, it is necessary to accelerate the coverage of COVID-19 vaccination among adults and continue adherence to non-pharmaceutical interventions.<\/jats:p>\n<\/jats:sec>","DOI":"10.1371\/journal.pmed.1003877","type":"journal-article","created":{"date-parts":[[2021,12,10]],"date-time":"2021-12-10T18:36:22Z","timestamp":1639161382000},"page":"e1003877","update-policy":"https:\/\/doi.org\/10.1371\/journal.pmed.corrections_policy","source":"Crossref","is-referenced-by-count":77,"title":["Seroprevalence of IgG antibodies against SARS-CoV-2 among the general population and healthcare workers in India, June\u2013July 2021: A population-based cross-sectional study"],"prefix":"10.1371","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1720-7628","authenticated-orcid":true,"given":"Manoj V.","family":"Murhekar","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tarun","family":"Bhatnagar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jeromie Wesley Vivian","family":"Thangaraj","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"V.","family":"Saravanakumar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muthusamy","family":"Santhosh Kumar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sriram","family":"Selvaraju","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kiran","family":"Rade","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C. P. Girish","family":"Kumar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R.","family":"Sabarinathan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3547-1393","authenticated-orcid":true,"given":"Smita","family":"Asthana","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9940-4878","authenticated-orcid":true,"given":"Rakesh","family":"Balachandar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sampada Dipak","family":"Bangar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Avi Kumar","family":"Bansal","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8788-2250","authenticated-orcid":true,"given":"Jyothi","family":"Bhat","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Debjit","family":"Chakraborty","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vishal","family":"Chopra","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dasarathi","family":"Das","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6595-2251","authenticated-orcid":true,"given":"Kangjam Rekha","family":"Devi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gaurav Raj","family":"Dwivedi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2207-3465","authenticated-orcid":true,"given":"Agam","family":"Jain","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1494-688X","authenticated-orcid":true,"given":"S. Muhammad Salim","family":"Khan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. Sunil","family":"Kumar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7799-271X","authenticated-orcid":true,"given":"Avula","family":"Laxmaiah","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3609-9797","authenticated-orcid":true,"given":"Major","family":"Madhukar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amarendra","family":"Mahapatra","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Talluri","family":"Ramesh","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1550-8416","authenticated-orcid":true,"given":"Chethana","family":"Rangaraju","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8821-6097","authenticated-orcid":true,"given":"Jyotirmayee","family":"Turuk","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8996-8998","authenticated-orcid":true,"given":"Suresh","family":"Yadav","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Balram","family":"Bhargava","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"name":"on behalf of the ICMR serosurveillance group","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2021,12,10]]},"reference":[{"key":"pmed.1003877.ref001","volume-title":"WHO coronavirus (COVID-19) dashboard.","year":"2021"},{"key":"pmed.1003877.ref002","unstructured":"Government of India. #IndiaFightsCorona COVID-19. New Delhi: Government of India; 2021 [cited 2021 Dec 8]. Available from: https:\/\/www.mygov.in\/covid-19."},{"key":"pmed.1003877.ref003","volume-title":"Population-based age-stratified seroepidemiological investigation protocol for coronavirus 2019 (COVID-19) infection, 26 May 2020, version 2.0","year":"2020"},{"key":"pmed.1003877.ref004","first-page":"48","volume-title":"Indian J Med Res","author":"MV Murhekar","year":"2020"},{"key":"pmed.1003877.ref005","first-page":"e257","volume-title":"Lancet Glob Health","author":"MV Murhekar","year":"2021"},{"key":"pmed.1003877.ref006","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1016\/j.ijid.2021.05.040","article-title":"SARS-CoV-2 seroprevalence among the general population and healthcare workers in India, December 2020\u2013January 2021","volume":"108","author":"MV Murhekar","year":"2021","journal-title":"Int J Infect Dis"},{"key":"pmed.1003877.ref007","volume-title":"Frequently asked questions.","author":"Ministry of Health and Family Welfare","year":"2021"},{"key":"pmed.1003877.ref008","volume-title":"C-13 single year age returns by residence and sex","author":"Office of the Registrar General & Census Commissioner","year":"2021"},{"key":"pmed.1003877.ref009","volume-title":"SARS-CoV-2 IgG assay","author":"Siemens Healthineers","year":"2021"},{"key":"pmed.1003877.ref010","volume-title":"EUA authorized serology test performance","author":"US Food and Drug Administration","year":"2021"},{"key":"pmed.1003877.ref011","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1016\/j.jinf.2021.05.026","article-title":"Persistence of humoral immune response to SARS-CoV-2 up to 7 months post-infection: cross-sectional study, South India, 2020\u201321","volume":"83","author":"JWV Thangaraj","year":"2021","journal-title":"J Infect."},{"key":"pmed.1003877.ref012","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1093\/aje\/kwaa174","article-title":"Adjusting coronavirus prevalence estimates for laboratory test kit error","volume":"190","author":"CT Sempos","year":"2021","journal-title":"Am J Epidemiol"},{"key":"pmed.1003877.ref013","doi-asserted-by":"crossref","first-page":"861","DOI":"10.1016\/j.cell.2021.01.007","article-title":"Adaptive immunity to SARS-CoV-2 and COVID-19","volume":"184","author":"A Sette","year":"2021","journal-title":"Cell"},{"key":"pmed.1003877.ref014","doi-asserted-by":"crossref","first-page":"eabe0367","DOI":"10.1126\/sciimmunol.abe0367","article-title":"Persistence and decay of human antibody responses to the receptor binding domain of SARS-CoV-2 spike protein in COVID-19 patients","volume":"5","author":"AS Iyer","year":"2020","journal-title":"Sci Immunol."},{"issue":"6570","key":"pmed.1003877.ref015","doi-asserted-by":"crossref","first-page":"995","DOI":"10.1126\/science.abj9932","article-title":"Genomic characterization and epidemiology of an emerging SARS-CoV-2 variant in Delhi, India","volume":"374","author":"MS Dhar","year":"2021","journal-title":"Science"},{"key":"pmed.1003877.ref016","article-title":"WHO Unity Seroprevalence study team of AIIMS. Serological prevalence of SARS-CoV-2 antibody among children and young age (between age 2\u201317 years) group in India: an interim result from a large multi-centric population-based seroepidemiological study.","author":"P Misra","year":"2021","journal-title":"medRxiv"},{"key":"pmed.1003877.ref017","doi-asserted-by":"crossref","first-page":"950","DOI":"10.1016\/S1473-3099(21)00070-0","article-title":"Safety and immunogenicity of an inactivated SARS-CoV-2 vaccine, BBV152: interim results from a double-blind, randomised, multicentre, phase 2 trial, and 3-month follow-up of a double-blind, randomised phase 1 trial","volume":"21","author":"R Ella","year":"2021","journal-title":"Lancet Infect Dis"},{"key":"pmed.1003877.ref018","unstructured":"Central Drugs Standard Control Organisation (CDSCO) . ChAdOx1 nCov-19 Corona Virus Vaccine (Recombinant) COVISHIELD. Summary of Product Characteristics.CDSCO, New Delhi; 2021 [cited 2021 July 29]. Available from: https:\/\/cdsco.gov.in\/opencms\/export\/sites\/CDSCO_WEB\/en\/Smpcserum.pdf"},{"key":"pmed.1003877.ref019","doi-asserted-by":"crossref","first-page":"6492","DOI":"10.1016\/j.vaccine.2021.09.055","article-title":"Antibody response after first and second-dose of ChAdOx1-nCOV (CovishieldTM) and BBV-152 (CovaxinTM) among health care workers in India: final results of Cross-sectional Coronavirus Vaccine-induced Antibody Titre (COVAT) study","volume":"39","author":"A Kumar Singh","year":"2021","journal-title":"Vaccine"},{"key":"pmed.1003877.ref020","doi-asserted-by":"crossref","first-page":"1140","DOI":"10.1038\/s41564-021-00947-3","article-title":"Antibody responses to SARS-CoV-2 vaccines in 45,965 adults from the general population of the United Kingdom","volume":"6","author":"J Wei","year":"2021","journal-title":"Nat Microbiol"},{"key":"pmed.1003877.ref021","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1038\/s41586-021-03647-4","article-title":"SARS-CoV-2 infection induces long-lived bone marrow plasma cells in humans","volume":"595","author":"JS Turner","year":"2021","journal-title":"Nature"},{"key":"pmed.1003877.ref022","doi-asserted-by":"crossref","first-page":"1227","DOI":"10.1126\/science.abd7728","article-title":"Robust neutralizing antibodies to SARS-CoV-2 infection persist for months","volume":"370","author":"A Wajnberg","year":"2020","journal-title":"Science"},{"key":"pmed.1003877.ref023","doi-asserted-by":"crossref","first-page":"1453","DOI":"10.1515\/cclm-2021-0214","article-title":"Clinical validation of the Siemens quantitative SARS-CoV-2 spike IgG assay (sCOVG) reveals improved sensitivity and a good correlation with virus neutralization titers","volume":"59","author":"C Irsara","year":"2021","journal-title":"Clin Chem Lab Med"},{"key":"pmed.1003877.ref024","doi-asserted-by":"crossref","first-page":"1459","DOI":"10.1016\/S0140-6736(21)00675-9","article-title":"SARS-CoV-2 infection rates of antibody-positive compared with antibody-negative health-care workers in England: a large, multicentre, prospective cohort study (SIREN).","volume":"397","author":"VJ Hall","year":"2021","journal-title":"Lancet"},{"key":"pmed.1003877.ref025","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1016\/j.chom.2021.02.010","article-title":"The great escape? SARS-CoV-2 variants evading neutralizing responses","volume":"29","author":"J Pr\u00e9vost","year":"2021","journal-title":"Cell Host Microbe"},{"key":"pmed.1003877.ref026","doi-asserted-by":"crossref","first-page":"1334","DOI":"10.1093\/infdis\/jiaa796","article-title":"SARS-CoV-2 Seroprevalence survey estimates are affected by anti-nucleocapsid antibody decline","volume":"223","author":"S Bolotin","year":"2021","journal-title":"J Infect Dis"}],"updated-by":[{"DOI":"10.1371\/journal.pmed.1003877","type":"new_version","label":"New version","source":"publisher","updated":{"date-parts":[[2022,1,4]],"date-time":"2022-01-04T00:00:00Z","timestamp":1641254400000}}],"container-title":["PLOS Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pmed.1003877","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,1,4]],"date-time":"2022-01-04T18:36:08Z","timestamp":1641321368000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pmed.1003877"}},"subtitle":[],"editor":[{"given":"Amitabh Bipin","family":"Suthar","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2021,12,10]]},"references-count":26,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2021,12,10]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pmed.1003877","relation":{"new_version":[{"id-type":"doi","id":"10.1371\/journal.pmed.1003877","asserted-by":"object"}]},"ISSN":["1549-1676"],"issn-type":[{"value":"1549-1676","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,12,10]]}}}