Published: 2021-03-25

Seroprevalence of SARS CoV 2 specific Ig G antibodies in District Srinagar, Kashmir: a population based study

Taha Ayub, Malik Waseem Raja, S. M. Salim Khan, Inaamul Haq, Mariya Amin Qureshi, Sabhiya Majid, Iqra Nisar Chowdri, Tanzeela Bashir Qazi, Rafiya Kousar, Abdul Aziz Lone, Iram Sabah, Shahroz Nabi, Ishtiyaq Ahmad Sumji, Misbah Ferooz Kawoosa, Shifana Ayoub, Mehvish Afzal Khan, Shaista Ismail, Anjum Asma, Munaza aziz


Background: The seroprevalence studies are conducted with the aim of estimating the extent of SARS CoV2 infection in any community. A cross sectional population based study was conducted in Srinagar district of Kashmir, India so as to provide relevant information on the proportion of people who have experienced a recent or past infection.

Methods: An estimated sample size of 2400 was calculated based on anticipated seroprevalence of 20% and an absolute error of 2.5%. 20 clusters were selected using 2 stage cluster sampling. A set of questions on a mobile based application i.e Epicollect 5 was used to collect information on various variables and 3-5 ml of venous blood was taken for Ig G antibody testing. Chemiluminiscent Microparticle Immunoassay (CMIA) procedure using fully automated analyser by Abbott with sensitivity of 100% and specificity of 99.6% was used to detect IgG antibodies against SARS COVID-2.

Results: 2480 eligible individuals participated in the study. The overall seroprevalence of Ig G antibodies against SARS-CoV 2 in the current study was 40.6% (95% CI 38.7-42.6), with seroprevalence being significantly higher among females (44.7% as compared to 37.5%).  Age standardized seroprevalence revealed that seroprevalence increased with the increasing age.

Conclusions: The findings of Seroprevalence study may fail to reveal the true picture of covid-19 infection as there were certain participants who were positive for COVID on RTPCR but were IgG negative. Thus, the individual variation of immune response to the virus, role of mucosal Ig A antibodies and T cell mediated immunity cannot be ruled out.


COVID 19, IgG antibodies, SARS CoV2, Seroprevalence, Srinagar

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World Health Organization. WHO Director-General’s opening remarks at the media briefing on COVID-19-. Available at: speeches/detail/whodirector-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020 (2020).

Guan W. Clinical characteristics of coronavirus disease 2019 in China.N. Engl. J. Med. Available at; (2020).

Alberto L. Garcia-Basteiro, Moncunill G, Dobano C. Seroprevalence of antibodies against SARS-CoV-2 among health care workers in a large Spanish reference hospital. Nat Commun. 2020;11(1):3500.

Stringhini S, Wisniak A, Piumatti G, Azman AS. Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Geneva, Switzerland (SEROCoV-POP):a population-based study. Lancet. 2020;396:313-19.

Gerco den Hartog, Schepp RM, Kuijer M, GeurtsvanKessel C, Beek JV, Rots N, et al. SARS-CoV-2–Specific Antibody Detection for Seroepidemiology: A Multiplex Analysis Approach Accounting for Accurate Seroprevalence .The Journal of Infectious Diseases®. 2020;222:1452-61.

Kumar MS, Bhatnagar T, Manickam P. National sero-surveillance to monitor the trend of SARS-CoV-2 infection transmission in India: Protocol for community-based surveillance. Indian J Med Res. 2020;151(5):419-23.

Worldometers. Worldometers Global coronavirus update. Available at: from Accessed on 15 November 2020

Khan SM, Qurieshi MA, Haq I, Majid S, Bhat AA, Nabi S, et al. Seroprevalence of SARS-CoV-2 specific IgG antibodies in District Srinagar, northern India–a cross-sectional study. PloS one. 2020;15(11):e0239303.

Folgueira MD, Munoz-Ruiperez C, Alonso-Lopez MA, Delgado R. SARS-CoV-2 infection in health care workers in a large public hospital in Madrid, Spain, during March 2020. Med Rxiv. 2020.

Epicollect5 - Free and easy-to-use mobile data-gathering platform. Available at:

SARS-CoV-2 Immunoassay Abbott Core Laboratory. Available at: disease/sars-cov-2.

Borges LP, Martins AF, Melo MS, Oliveira MGB, Neto JMR, Dósea MB, et al. Seroprevalence of SARS-CoV-2 IgM and IgG antibodies in an asymptomatic population in Sergipe, Brazil. Rev Panam Salud Publica. 2020;44:e108.

Stringhini S, Wisniak A, Piumatti G, Azman AS, Lauer SA, Baysson H, et al. seroprevalence of anti-SARS-CoV-2 IgG antibodies in Geneva, Switzerland (SEROCoV POP): a population-based study. Lancet. 2020;396:313-9.

Havers FP, Reed C, Lim T, Montgomery JM, Klena JD, Hall AJ, et al. Seroprevalence of Antibodies to SARS-CoV-2 in 10 Sites in the United States, March 23-May 12, 2020. JAMA Intern Med. 2020.

Pollán M, Pérez-Gómez B, Pastor-Barriuso R, Oteo J, Hernán MA, Pérez-Olmeda M, et al. Prevalence of SARS-CoV-2 in Spain (ENE-COVID): a nationwide, population-based seroepidemiological study. Lancet. 2020;396.

Shakiba M, Hashemi Nazari SS, Mehrabian F, Rezvani SM, Ghasempour Z, Heidarzadeh A. Seroprevalence of COVID-19 virus infection in Guilan province, Iran. medRxiv. Cold Spring Harbor Laboratory Press; 2020.

Doi A, Iwata K, Kuroda H, Hasuike T, Nasu S, Kanda A, et al. Estimation of seroprevalence of novel coronavirus disease (COVID-19) using preserved serum at an outpatient setting in Kobe, Japan: A cross-sectional study. Infectious Diseases (except 361 HIV/AIDS). 2020.

Snoeck CJ, Vaillant M, Abdelrahman T, Satagopam VP, Turner JD, Beaumont K, et al. Prevalence of SARS-CoV-2 infection in the Luxembourgish population the CON-VINCE study. Medrxiv. 2020.

Sood N, Simon P, Ebner P, Eichner D, Reynolds J, Bendavid E, et al. Seroprevalence of SARS-CoV-2-Specific Antibodies among Adults in Los Angeles County, California, on April 10-11, 2020. JAMA - Journal of the American Medical Association. American Medical Association; 2020.

Sero-prevalence study conducted by National Center for Disease Control NCDC, 371 MoHFW, in Delhi, June 2020. 2020. Available at:

Ray A, Singh K, Chattopadhyay S, Mehdi F, Batra G, Gupta A, et al. Seroprevalence of anti-SARS-CoV-2 IgG antibodies in hospitalized patients at a tertiary referral center in North India.

Population-based seroprevalence surveys of anti-SARS-CoV-2 antibody: An up-to-date review Chih-Cheng Laia, Jui-Hsiang Wanga, Po-Ren Hsueh.International Journal of Infectious Diseases 101. 2020:314-22.

Faustini SE, Jossi SE, Perez-Toledo M. Detection of antibodies to the SARS-CoV-2 spike glycoprotein in both serum and saliva enhances detection of Infection. MedRxiv. 2020.

Long Q-X, Tang X-J, Shi Q-L. Clinical and immunological assessment of asymptomatic SARS-CoV-2 infections. Nat Med 2020;26:1200-4.

Pawelec G Weng NP.Can an effective SARS-CoV-2 vaccine be developed for the older population?. Immun Ageing. 2020;17:8.

Letter to editor. Seroprevalence of SARSCoV 2 significantly increases with age: Preliminary results from a population mass screening. Journal of infection.m5G. 2020;17:12.

Yang J, Zheng Y, Gou X, Pu K, Chen Z, Guo Q, et al. Prevalence of comorbidities in the novel Wuhan coronavirus (COVID-19) infection: a systematic review and meta-analysis. Int J Infect Dis. 2020;94:91-5.

Wang W, Su B, Pang L, Qiao L, Feng Y, Ouyang Y, et al. . High-dimensional immune profiling by mass cytometry revealed immunosuppression and dysfunction of immunity in COVID-19 patients. Cell Mol Immunol. 2020;17:650-2.

Emami A, Javanmardi F, Pirbonyeh N, Akbari A. Prevalence of underlying diseases in hospitalized patients with COVID-19: a systematic review and meta-analysis. Arch Acad Emerg Med. 2020;8:e35.

Lauren A. Callender, Michelle Curran, Stephanie M. Bates, MaelleMairesse, Julia Weigandt, Catherine J. Betts. The Impact of Pre-existing Comorbidities and Therapeutic Interventions on COVID-19. Front Immunol. 2020.

Linda Hueston, Jen Kok, Ayla Guibone, Damien McDonald, George Hone et al.The Antibody Response to SARS-CoV-2 Infection.Open Forum Infect Dis. 2020;7(9):ofaa387.

Wu, J. SARS-CoV-2 infection induces sustained humoral immune responses in convalescent patients following symptomatic COVID-19. Preprint at medRxiv. 2020.

Liu A, Li Y, Peng J, Huang Y, Xu D. Antibody responses against SARS‐CoV‐2 in COVID‐19 patients. 2020.

Sekine T, Perez-Potti A, Rivera-Ballesteros O. Robust T cell immunity in convalescent individuals with asymptomatic or mild COVID-19. Cell2020.

Sungnak W, Huang N, Bécavin C. HCA Lung Biological Network. SARS-CoV-2 entry factors are highly expressed in nasal epithelial cells together with innate immune genes. Nat Med. 2020;26:681-7.

Corthésy B. Multi-faceted functions of secretory IgA at mucosal surfaces. Front Immunol. 2013;4:185.

Ma H, Zeng W, He H. Serum IgA, IgM, and IgG responses in COVID-19. Cell Mol Immunol. 2020;17:773-5.

Guo L, Ren L, Yang S. Profiling Early Humoral Response to Diagnose Novel Coronavirus Disease (COVID-19). Clin Infect Dis. 2020;71:778-85.

Knabl L, Mitra T, Kimpel J. High SARS-CoV-2 seroprevalence in children and adults in the Austrian ski resort Ischgl. MedRxiv. 2020.

Kontou PI, Braliou GG, Dimou NL, Nikolopoulos G, Bagos PG. Antibody tests in detecting SARS-CoV-2 infection: A meta-analysis. Diagnostics. 2020;10.

Okba NMA, Müller MA, Li W, Wang C, Geurtsvankessel CH, et al. Severe Acute Respiratory Syndrome Coronavirus 2-Specific Antibody Responses in Coronavirus Disease Patients. Emerg Infect Dis. 2020;26:1478-88.