The RECOVERY Collaborative Group conducted a randomized, controlled, open-label trial to evaluate the effectiveness of hydroxychloroquine in hospitalized patients with COVID-19. The primary outcome was 28-day mortality, and the secondary outcomes included time to hospital discharge and the need for invasive mechanical ventilation or death among those not on invasive mechanical ventilation at baseline. A total of 1561 patients were randomized to hydroxychloroquine and 3155 to usual care. The results showed no significant difference in 28-day mortality between the two groups (421 [27.0%] vs. 790 [25.0%]; rate ratio 1.09; 95% CI 0.97 to 1.23; P=0.15). However, patients allocated to hydroxychloroquine had a longer hospital stay and a higher risk of progressing to invasive mechanical ventilation or death. The study concluded that hydroxychloroquine was not an effective treatment for hospitalized patients with COVID-19.The RECOVERY Collaborative Group conducted a randomized, controlled, open-label trial to evaluate the effectiveness of hydroxychloroquine in hospitalized patients with COVID-19. The primary outcome was 28-day mortality, and the secondary outcomes included time to hospital discharge and the need for invasive mechanical ventilation or death among those not on invasive mechanical ventilation at baseline. A total of 1561 patients were randomized to hydroxychloroquine and 3155 to usual care. The results showed no significant difference in 28-day mortality between the two groups (421 [27.0%] vs. 790 [25.0%]; rate ratio 1.09; 95% CI 0.97 to 1.23; P=0.15). However, patients allocated to hydroxychloroquine had a longer hospital stay and a higher risk of progressing to invasive mechanical ventilation or death. The study concluded that hydroxychloroquine was not an effective treatment for hospitalized patients with COVID-19.