Effect of hydroxychloroquine on SARS-CoV-2 viral load in patients with COVID-19

Faico-Filho, K. S.; Conte, D. D.; Souza Luna, L. K.; Carvalho, J. M. A.; Perosa, A. H. S.; Bellei, N.

Background: Some studies have shown that hydroxychloroquine (HCQ) is an effective drug in reducing the in vitro replication of SARS-CoV-2. However, the in vivo effect of HCQ still unclear. This study aims to evaluate viral load clearance in patients with COVID-19 who underwent HCQ treatment in comparison with a control group that did not receive the drug. Methods: This prospective study comprised consecutive viral load measurements in patients with COVID-19 hospitalized with a moderate illness. Patients received 400 mg of HCQ every 12 hours for 10 days according to the medical decision. Nasal swab samples were collected at the 1st, 7th, and 14th days of the admission. Results: 155 samples were collected from 66 patients with COVID-19 (60% female), with a median age of 58 years. The viral load between studied groups, assumed as a semiquantitative measure of cycle threshold (Ct) values, presented no significant difference within the three consecutive measures ({Delta}Ct) (p>0.05). We also analyzed the {Delta}Ct viral load at different intervals of sample collection ({Delta}t <7; 7-12 and >12 days) without significant differences at any {Delta}Ct (p>0.05). Conclusion: In this study, we did not observe any change in viral load in vivo with the use of HCQ.