Severe acute respiratory syndrome coronavirus-2 IgG antibodies among health-care workers in a tertiary care hospital in Delhi India

Abstract

Introduction: COVID-19 is a novel viral disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that was first detected in Wuhan, China, in December 2019. Hospital health care workers (HCW's) are the frontline workforce for clinical care of cases and they are exposed to a higher risk of acquiring the disease than the general population. Thus, this study was planned with the aim to detect the presence of IgG antibody against SARS-CoV2 among the HCW's. Materials and Methods: This retrospective study was carried out from June to August 2020 among the HCW's of a tertiary care hospital in New Delhi. Information on demography, risk factors and COVID-19 infection was obtained on predesigned pro forma and the blood sample was collected in the plain vial for the detection of COVID 19 IgG antibodies, targeting recombinant Spike 2 protein and nucleoprotein, using the Indian Council of Medical Research approved enzyme-linked immunosorbent assays kit. Results: Eight hundred HCWs voluntarily participated in the study. The seroconversion rate among the HCW's enrolled in our study was found to be 16.75%. They were divided into three groups on the basis of reverse transcription-polymerase chain reaction (RT PCR) test done for SARS-CoV2 genes since 30 January 2020. In Group I, who were RT PCR positive, 34 (70.8%) were found to be seroconverted. In Group II who were RT PCR negative, 12.09% had IgG antibodies. Group III comprised 529 HCW's, who never got themselves tested for RT PCR, of these 13.8% had developed IgG antibodies. The most common symptom was found to be cough, fever, bodyache, loss of taste and loss of smell. The odds ratio amongst seroconverted and nonseroconverted HCW's was found to be significant in all the symptoms except for nasal discharge and sore throat. Among the significant symptoms the odds ratio was observed to be 16.09 and 12.99 for loss of taste and loss of smell, respectively, and was observed to be highly significant (P < 0.001). Only 1.5% had moderate and severe infection and the rest had mild infection or were asymptomatic. Seroconversion rate among the asymptomatic HCWs was found to be 10.84%. Conclusion: Serology plays an important role in understanding the pandemic COVID-19 by identifying the individuals who have been infected and seroconverted, infected but not seroconverted, infected and remained asymptomatic or who never got themselves tested but showed the presence of IgG antibodies.