Hydroxychloroquine pre-exposure prophylaxis for COVID-19 among healthcare workers: Initial experience from India

Background: Hydroxychloroquine (HCQ) had generated considerable interest for coronavirus disease 2019 (COVID-19) prophylaxis. We conducted a prospective observational study at a tertiary care hospital in India, with dedicated COVTD-19 care facilities. Objectives: Primary objective was incidence of adverse effects, secondary objective being efficacy in preventing COVID-19. Methods: Healthcare workers were recruited and grouped based on voluntary HCQ prophylaxis as per national guidelines. Side effects in HCQ group were graded in accordance with national cancer institute-common terminology criteria for adverse events (NCI-CTCAE) version 5.0. At 3-7-week follow-up, groups were compared for COVID-19 exposure, symptoms development and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RT-PCR results. Results: Among 358 participants recruited, 216 (60.3%) were males and mean age was 31.2 +/- 6.6 years. Chemoprophylaxis was initiated by 258 (72%) participants. After loading dose, 7 (2.7%) reported grade 2 and 1 (0.4%) grade 3 adverse effects. Discontinuation of HCQ due to side effects was reported in 11 (4.3%) participants. Electrocardiogram was done by 50 (19.4%) participants on HCQ; no abnormalities were noted. A total of 106 (41%) among those taking and 63 (63%) among those not taking HCQ were tested for SARS-CoV-2 due to influenza-like illness or significant exposure. Among all participants, 25 (6.9%, 95% confidence interval [CI] 4.3-9.6) developed COVID-19 during the study period. In the group taking HCQ 10 (3.9%) tested positive compared to 15 (15%) in the group not taking HCQ (P< 0.001). Odds ratio with HCQ intake was 0.34 (95% CI 0.13-0.83, P= 0.01) and the number needed to treat was 12. Conclusion: IICQ is safe at the recommended dose for pre-exposure prophylaxis of COVID-19.