Abstract

Background: SARS-CoV-2 (Severe acute respiratory syndrome corona virus 2) seroprevalence studies are being conducted all over the world to identify the level of exposure to the virus, thus giving us a true estimate of the hidden burden of infection in undiagnosed asymptomatic subjects.
Aim: To determine the serological status for SARS CoV 2 among unvaccinated frontline health care workers in a Covid designated hospital.
Materials and methods - A mono-centric, retrospective, observational, cross sectional study was carried out with the institutional ethical committee approval (CTRI/2021/03/031933). 269 HCW were tested for SARS COV-2 antibodies. Out of these, 250 were frontline HCWs posted in Covid wards. Their data on demographics and symptomology was collected through validated Questionnaires. HCWswith active symptoms and a positive RT-PCR history of less than 14 days at the time of testing were excluded. IgG antibodies were detected by CLIA with 100% sensitivity and 99.8% specificity. A p value of Results: Data regarding RT-PCR and serological status was collected from all the 250 subjects, but only 174 questionnaires which were completed was analyzed statistically. Among the 250 subjects, 43(17.2%, 95%CI: 0.125,0.219) were seropositive and 14(5.6%) were positive for RTPCR. 70%(n=30) of the seropositive HCWs were totally asymptomatic. About 84% of the asymptomatic seropositive subjects were RT-PCR negative, thus reflecting the hidden burden of the infection. Further statistical analysis on the background characteristics was done only for 174 individuals out of the 250 HCWs. 19% of the medical staff were reactive compared to 37.7% of reactivity among the non-medical staff and this was the only statistical significance observed(p=0.008). No significant difference was noted with respect to gender, age, department, BCG vaccination, use of immune boosters or HCQ, no of days of exposure.
Conclusion: This analysis helped us generate a pre vaccination baseline information regarding the proportion of asymptomatic / symptomatic frontline workers with respect to serological status. If asymptomatic, they remain undiagnosed, thus playing a significant role in  Covid transmission and crippling the healthcare system, and emphasize on educating our non-medical staff on the importance of PPE use, provides an opportunity for generating a database and data comparison of this newly emerged viral disease, thus helping in predicting and monitoring the future course of the pandemic.