An Open Label Randomized Controlled Trial of Ivermectin Plus Favipiravir-Based Standard of Care versus Favipiravir-Based Standard of Care for Treatment of Moderate COVID-19 in Thailand

Background: The role of ivermectin in the treatment of moderate coronavirus disease 2019 (COVID-19) is controversial. We performed an open label randomized controlled trial to evaluate the role of ivermectin plus favipiravir-based standard of care versus favipiravir-based standard of care for the treatment of moderate COVID-19 infection.

Materials and methods: An open-label randomized control trial was performed at Thammasat Field Hospital and Thammasat University Hospital from October 1st, 2021 to May 31st, 2022. Patients with moderate COVID-19 infections were randomized to the intervention (ivermectin plus favipiravir-based standard of care) or control group (favipiravir-based standard of care alone). Patients were followed up to 21 days. The primary outcome was the improvement in World Health Organization (WHO) category ordinal scale by 2 points. Secondary outcomes included duration of illness, development of severe COVID-19, and adverse reactions.

Results: There were 157 patients in the intervention and 160 patients in the control group. Characteristics, underlying diseases, and risk factors for severe COVID-19 were comparable in both groups. Improvement in the WHO-category ordinal scale by 2 points was achieved in 98.7% of the intervention group and in 99.4% of the control group (relative risk [RR]: 0.487; 95% confidence interval [CI]: 0.044-5.430). The median illness duration was 5.0 days (range, 3 - 28 days) in intervention group versus 5.2 days (range, 3 - 28 days) in control group (P = 0.630). Severe COVID-19 that required intensive care occurred in 2 patients (1.3%) in the intervention group and 1 patient (0.6%) in the control group (RR: 2.052; 95% CI: 0.184 - 22.857). No significant difference in serious drug adverse events was seen.

Conclusion: In this study ivermectin plus standard of care was not associated with improvement in the WHO-category ordinal scale, reduced illness duration, or development of severe COVID-19 in moderately ill COVID-19 patients.

Trial registration: Clinicaltrials.gov Identifier: TCTR20220427005.