Abstract: Original Article Hydroxychloroquine/Chloroquine Prophylaxis among Health‑care Workers: Was it Really Preventive? – Evidence from a Multicentric Cross‑sectional Study Arun Kumar Yadav, Atul Kotwal1, Subhadeep Ghosh2 Department of Community Medicine, Armed Forces Medical College, Pune Maharashtra, 1Executive Director, NHSRC, 2Department of Community Medicine, ACMS, New Delhi, India Abstract Background: Despite the low level of clinical evidence in hydroxychloroquine (HCQ) favor, it was prescribed for pre‑ and post‑exposure prophylaxis in India and worldwide. In absence of a large randomized control trial, the evidence needs to be generated through observation study, hence the study was conducted to find the evidence for prophylaxis of HCQ. Materials and Methods: A multi‑centric cross‑sectional study involving government hospitals was chosen for serosurvey conducted from August 21, 2020, to November 20, 2020. Questionnaire was adopted from WHO. Data about chloroquine (CQ) use among health‑care workers (HCWs) were added and the duration of CQ intake was also noted. Results: A total of 2,224 HCWs were recruited. The mean duration of time of taking HCQ was 7.1 weeks (standard deviation ± 6.1 weeks, median = 4 weeks with IQR, 3–10 weeks). Training on personal protective equipment (PPE), knowledge of handwashing, direct care to the patient, availability of alcohol hand rub, close contact with the patient, duration of contact, and usage of PPE were associated with HCQ intake. The antibody formation in group taking HCQ was 16.9% compared to 19.8% not taking it (P = 0.08). The Chi‑square for linear trend for weeks of HCQ intake and antibody formation. However, the same was not statistically significant (Chi‑square = 3.61, P = 0.06). Conclusion: Our study did not find a statistically significant association in the large multicentric study. The absolute difference of 2.9% in the two groups may not be sufficient to warrant its widespread use for prophylaxis. Keywords: Chemo‑prophylaxis, COVID‑19, hydroxychloroquine Hydroxychloroquine (HCQ), the widely used drug for rheumatologic conditions, attracted widespread interest for the prevention of severe acute respiratory syndrome coronavirus‑2 (SARS‑CoV‑2) infection. Despite a low level of clinical evidence in its favor, the necessity of coronavirus disease (COVID‑19) pandemic, saw it being officially prescribed for pre‑ and post‑exposure prophylaxis in India as well as worldwide. The in‑vitro, as well as observational studies, provided scant evidence regarding the effectiveness of HCQ in the prophylaxis of SARS‑CoV‑2 infection.[1,2] An observational study in South Korea at the beginning of the pandemic, using postexposure prophylaxis with HCQ after a large COVID‑19 exposure event in a hospital, showed all follow‑up PCR tests as negative.[3] The Indian National Task Force for COVID‑19 on March 22, 2020, recommended HCQ on the basis of Access this article online Quick Response Code: Website: www.ijcm.org.in DOI: 10.4103/ijcm.ijcm_684_21 202 in vitro and preclinical data for prophylaxis of health‑care workers (HCWs) and household contacts with caution and strict advisory for extensive reporting of adverse reactions.[4,5] A systematic review showed the prophylactic effects of chloroquine (CQ) and HCQ against SARS‑CoV‑2. [6] Although preclinical results were promising, to date there is a dearth of evidence to support the efficacy of CQ or HCQ in preventing COVID‑19. Considering potential safety..