The use of ivermectin does not appear to significantly shorten the duration of symptoms in patients with mild coronavirus disease 2019 (COVID-19), according to findings from a randomized clinical trial published in JAMA.

Ivermectin, an antiparasitic agent, continues to be widely used as a potential treatment for COVID-19 based on experimental studies showing antiviral activity during the early stages of other infections. To assess its effect on the duration of symptoms in patients with mild COVID-19, the study authors conducted a double-blind, randomized trial in a single site in Cali, Colombia ( NCT04405843).

Using the state’s health department electronic database, study participants were selected if they had laboratory-confirmed COVID-19 with mild disease and symptom duration of 7 days or less. A total of 476 adults were enrolled and 400 (the primary analysis population; median age, 37 years; 58% women) were randomly assigned to receive ivermectin 300μg/kg of body weight/day for 5 days (n=200) or placebo (n=200). The primary outcome measure of the study was the time to complete resolution of COVID-19 symptoms within the 21-day follow-up period.

Among the 398 patients that completed the trial, results showed the median time to resolution of COVID-19 symptoms was 10 days (interquartile range [IQR], 9-13) for patients who received ivermectin and 12 days (IQR, 9-13) for those who received placebo (hazard ratio 1.07 [95% CI, 0.87-1.32]; P =.53). By day 21, symptoms had resolved for 82% of the ivermectin-treated group and 79% of the placebo group.

As for safety, adverse events were reported by 77% of the ivermectin group and 81.3% of the placebo group. Headache was the most common solicited adverse event (52% in the ivermectin group and 56% in the placebo group).

The authors noted several limitations of the trial including a change in study design 6 weeks in (the original outcome measure was meant to assess clinical deterioration), a lack of virological assessments, and a young study population. 

“The findings do not support the use of ivermectin for treatment of mild COVID-19, although larger trials may be needed to understand the effects of ivermectin on other clinically relevant outcomes,” the authors concluded.

Disclosure: Some authors have declared affiliations with or received funding from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


López-Medina E, López P, Hurtado IC, et al. Effect of ivermectin on time to resolution of symptoms among adults with mild COVID-19. [Published online March 4, 2021]. JAMA doi:10.1001/jama.2021.3071.