Serosurveillance of SARS CoV 2 among the healthcare workers of a tertiary care teaching institution in Central Kerala during the post lockdown phase

Abstract

Background. Kerala was the first state to have the confirmed case of COVID 19 in the country and it was first confirmed in Thrissur district on 30 January 2020.Our institute being in the heart of the city had to take adequate measures to mitigate the spread and treat the required patients by keeping its staff safe & healthy. The hallmark of COVID 19 infection is high infectivity, pre symptomatic transmission and asymptomatic prevalence which could result in high cumulative numbers of infections, hospitalizations, and deaths. Kerala was the first state to confirm community transmission in July 2020.Health care workers being in the forefront in the war against COVID19 are very prone in acquiring the infection and are possible to be asymptomatic sources for cluster formation. Knowing the development of immunity as shown by the presence of anti COV2 antibodies in the population contributes to the epidemiological understanding of the disease. The intent of the study is to do an antibody testing in our hospital to find the serosurveillance of SARS CoV 2 among the healthcare workers in our hospital. Aim: To estimate the seropositivity of SARS CoV 2 among the healthcare workers at Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, six months after revoking the lockdown Methodology: A cross sectional study among the health care workers of the medical college. Multistage Sampling was done with the hospital block as the first stage and departments as the second stage. In the final stage of sampling the test individuals were selected on a first come first served basis after the antibody test availability was declared open and free for all staff. A consent form and a Google form were given to all staff who volunteered for participating in the study. Each consented participant recruited into the investigation completed a questionnaire which covers details regarding demographics, exposure history, Residence & travel. Blood sample was collected and Anti SARS COV2 IgG antibody testing which targets the Spike Protein 1(SP1) was done using the VITROS chemiluminescence platform (Orthoclinical diagnostics, USA). Sampling & testing ranged over a time frame from September 5th to December 15th, 2020 Results: Jubilee Mission Medical College has 2785 working staff at the time of study. A total of 423 staff consented and their samples were tested. 37 staff members tested positive for COVID 19 antibody, yielding an overall prevalence of 8.75% (95% CI, 6.23 to 11.86). 86.5 % (32/37) of them were having a history of COVID-19 Antigen / RT PCR Positivity. We identified a statistically significant linear trend (p value =0.00001), between seropositivity and the degree of severity of COVID 19. Among the various factors which increase the risk of seroconversion, history of undergoing quarantine (p value < 0.001), contact with a confirmed case (p value = 0.002), contact with a caregiver for COVID 19 (p value =0.001) and history of Upper respiratory symptoms (p value =0.001), were found to be significantly associated with positive serology. Conclusions: The overall seropositivity in the current study was found to be 8.75% which is comparable to seroprevalence studies conducted in the United States and Wuhan in China. The pattern of seropositivity across the different category of health workers observed in the present study showed a higher prevalence among nurses. This result is also in agreement with a recent published report from united states. Various measures advised by the national and state health authorities were adequately adhered to. Keeping track of the pattern of development of immunity in the community is part of understanding the illness and forecasting the spread. For the tested HCW, it will boost up morale by ending uncertainty. For the hospital administration it will help in decision making about relative focusing of interventions on patients in general and HCWs. By knowing the immunity status of HCWs, the Institution will be able to contribute authentically to the development of intervention strategies and guidelines from time to time, besides following the available guidelines. Being an educational institution, it is obligatory to train all the elements of care delivery to the future generation of health care workers. Getting experienced from a small but relevant sample was expected to facilitate larger community study envisaged in peripheral areas Jubilee served