HCQ for Primary Prophylaxis Against COVID19 in Health-care Workers

Background: Aim: To demonstrate the efficacy of low-dose hydroxychloroquine as primary prevention in healthcare workers Design, participants and interventions: Prospective, randomized, parallel group, double-blinded, placebo controlled, study. including 440 participants who will be randomised to 2 treatment arms: hydroxychloroquine or placebo. Outcome variables: symptomatic or asymptomatic SARS-CoV-2 infection confirmed by PCR, viral load during SARS-CoV-2 infection, seroconversion during the study period, incidence of any acute respiratory infection, days of sick leave. Statistical considerations: No trials have been published investigating the efficacy of HCQ as primary prophylaxis of SARS-CoV-2 infection in health care workers. Thus, sample size calculations in the proposed trial are based on the investigators' best estimates for several parameters. In accordance to the effect of oseltamivir against symptomatic influenza, we assumed an approximate effectiveness of approximately 60% (HR of 0.4) (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6464969/) as realistic. As a prophylactic intervention with HCQ, which may have side effects and for which supply shortage can be expected, was judged justifiable only if its effectiveness is high, we based our sample size consideration on a HR of 0.3. To estimate the probability of an event in both the experimental and the control group, very little data is available. In a Dutch point-prevalence study 0-10% of health-care workers were infected depending on the healthcare institution, depending on the hospital. This point-prevalence study was performed between 6 and 9 March, when the reported number of cases in the Netherlands was 33 and 77, respectively, according to the RIVM (https://www.rivm.nl/nieuws/resultaat-steekproef-4-ziekenhuismedewerkers-heeft-coronavirus). Additionally, in an a report published in the Lancet, 20% of responding healthcare workers in Italy were found to be infected with SARS-CoV2 within less than