Effects of Ivermectin on COVID-19 Symptom Resolution

Ivermectin did not significantly improve time to resolution of novel coronavirus (COVID-19) symptoms in adults with mild cases of the infection compared to placebo, according to a paper published in JAMA.

Investigators from Colombia conducted a randomized trial among adult COVID-19 patients in order to determine the effect of ivermectin on the duration of symptoms in patients with mild cases. The study authors noted that ivermectin is “widely” prescribed for COVID-19 treatment despite uncertainty about any clinical benefit.

Patients were randomized to either receive ivermectin (300 μg/kg of body weight per day for 5 days) or placebo. There were 200 patients in each group between July and December 2020. The COVID-19 patients were confirmed to have the infection based on results of PCR or antigen tests. The cohorts were balanced in demographic and disease characteristics at baseline, the investigators noted. Additionally, the median age was 37 years, a slight majority (58 percent) were women, and 79 percent did not have any known comorbidities at baseline.

Patients were asked to take ivermectin on an empty stomach, except on the first day of the study when it was administered after a screening and the randomization process.

The study authors followed up with the patients for 21 days and used an 8-category ordinal scale similar to the one used in other COVID-19 trials. No clinical evidence of infection begins the scale at 0, progressing to hospitalization requiring supplemental oxygen at 4 and concluding with death at 7. The study authors also defined time to recovery as the first day during the 21 days of follow-up where the patient reported a score of 0.

The most common symptoms were myalgia, headache, smell and taste disturbances, and dry cough, the study authors said, while adding that most patients were still able to perform their routine activities and were at home.

Overall, though, the study authors learned the time to resolution of symptoms in patients assigned to ivermectin compared to placebo was not significantly different, they wrote. The difference was 10 days for ivermectin compared to 12 days using placebo. By day 21, the study authors observed symptom resolution in 82 percent of the ivermectin patients and 79 percent of the placebo cohort. The study authors also found that the type of placebo did not alter the results; neither ivermectin vs. dextrose in saline or ivermectin vs. manufacturer’s placebo was much different.

Based on the 8-category scale, the investigators saw that few patients had a clinical deterioration of 2 or more points. This was not different between the 2 treatment cohorts, they said. There was also no significant difference in the proportion of patients who required escalation of care in the 2 cohorts. The length of time to this escalation of treatment, the proportion of patients who developed fever, or the duration of fever were also not significantly different between the groups.

Adverse events were reported in 77 percent of the ivermectin group and 81 percent of the placebo group between baseline and day 21, the study authors observed, adding that 15 patients in the ivermectin group and 5 patients in the placebo group discontinued treatment due to an adverse event. There were serious adverse events developed in 4 patients (2 in each cohort) but none were related to the trial medication, according to the study authors.

“Among adults with mild COVID-19, a 5-day course of ivermectin, compared with placebo, did not significantly improve the time to resolution of symptoms,” the study authors concluded. “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.”