As COVID-19 continues to spread, medical institutes across the world are working towards strategies to prevent the disease.  The current strategies, however, are limited to non-pharmacologic interventions. Several studies have indicated the effectiveness of hydroxychloroquine in the prevention of COVID-19, but definitive evidence is lacking. This study aims to investigate the efficacy of hydroxychloroquine for the prevention of COVID-19.

This open-label, cluster-randomized trial included a total of 2,314 healthy asymptomatic contracts of patients with PCR-confirmed COVID-19. The patients were randomly assigned in a 1:1 ratio to receive hydroxychloroquine or usual care. The primary outcome of the study was PCR-confirmed symptomatic COVID-19 within 14 days after exposure.

The findings showed similar results in the hydroxychloroquine and the usual-care group. The incidence of PCR-confirmed, symptomatic COVID-19 was 5.7% in the usual care group and 6.2% in the usual-care group. In addition, hydroxychloroquine was not found to be superior to usual care for lower transmission (18.7% vs. 17.8%). The incidence of serious adverse events was also higher in the hydroxychloroquine group (56.1%) compared with the usual-care group (59%).

The research concluded that postexposure therapy with hydroxychloroquine was not associated with a lower incidence of PCR-confirmed, symptomatic COVID-19 when compared with usual care.