Title: Immunity status of Health Care Workers post recovery from COVID-19: An online longitudinal panel survey

Shah, S. B.; Chawla, R.; Pahade, A.; Bansal, N.; Mehta, A.; Dewan, A. K.; Parkash, A.; Bhatia, M.

Abstract Background: Corona virus has literally travelled 'around the world in 80 days' akin to Fogg and Passepartoute of Jules Verne fame. Manning of corona virus disease 2019 (COVID-19) wards and ICUs, also surgery on COVID-positive patients is increasingly being relegated to that subset of health care workers (HCW) who themselves have resumed duties after surviving COVID-19 infection. Convalescent plasma therapy has been widely endorsed. Several vaccines are in the pipeline as potential preventive measures against the virus keeping HCW on the priority-list of recipients. Immunity passports are being validated for foreign travel. These events share a common presumption that exposure to COVID-19 virus (natural infection/inoculation) produces protective adaptive immunity. It is unknown whether all (COVID-19) infected patients mount a protective immune response and for how long any protective effect will last. Methods: This single institutional prospective longitudinal panel survey questions were deployed to the respondents online via email/WhatsApp groups to ascertain the symptomology and immunity status of HCW in the months following COVID-19 infection. The survey was administered to the same set/cohort of health care workers over 6 months. Results: 165 responses from 151 respondents (70 at 1-2months; 95 at 3-4 months including 14 at both time points) were analysed.7.14% of infected HCW failed to develop IgG antibodies at 4-6 weeks. 91.7% HCW with IgG titres in the highest bracket had experienced anosmia. Mean antibody titres were 12.08 {+/-} 9.56 and 9.72 {+/-} 9.34 at 1-2 months and 3-4 months post-development of first symptom, respectively. Conclusion: Understanding of COVID-19 patterns of variation in HCW may guide their deployment in the COVID ward and COVID-OTs. Revelation of this enigma (by quantification of serial IgG antibody levels) is critical for predicting response to vaccines under trial, fostering effective stratagems and tactics for pandemic control, ascertaining validity of immunity passports and understanding longevity/durability of protection by forecasting immunological memory against SARS-CoV-2.