We investigated Favipiravir (FPV) efficacy in mild cases of COVID-19 without pneumonia and its effects towards viral clearance, clinical condition, and risk of COVID-19 pneumonia development. PCR-confirmed SARS-CoV-2-infected patients without pneumonia were enrolled (2:1) within 10 days of symptomatic onset into FPV and control arms. The former received 1800 mg FPV twice-daily (BID) on Day 1 and 800 mg BID 5-14 days thereafter until negative viral detection, while the latter received supportive care only. The primary endpoint was time to clinical improvement, which was defined by a reduced National Early Warning Score (NEWS) or score of <1. 62 patients (41 female) comprised the FPV arm (median age: 32 years, median BMI: 22 kg/m2) and 31 patients (19 female) comprised the control arm (median age: 28 years, median BMI: 22 kg/m2). The median time to sustained clinical improvement by NEWS was 2 vs 14 days for FPV and control arms respectively (adjusted hazard ratio (aHR) of 2.77, 95% CI 1.57-4.88, P <0.001). The FPV arm also had significantly higher likelihoods of clinical improvement within 14 days after enrolment by NEWS (79% vs 32% respectively, P <0.001), particularly female patients (aOR 6.35, 95% CI 1.49-27.07, P <0.001). 8 (12.9%) and 7 (22.6%) patients in FPV and control arms developed mild pneumonia at a median (range) 6.5 (1-13) and 7 (1-13) days after treatment, respectively (P = 0.316); all recovered well without complications. We can conclude that early treatment of FPV in symptomatic COVID-19 patients without pneumonia was associated with faster clinical improvement.

The authors have declared no competing interest.

TCTR20200514001

This study was funded by the National Research Council of Thailand under grant and the Siriraj Research and Development Fund, Faculty of Medicine Siriraj Hospital, Mahidol University.

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Ethics committee/IRB of Siriraj Institutional Review Board and the institutional review board of Bamrasnaradura infection disease institute gave ethical approval for this work

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