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“The study results do not support the use of ivermectin for patients with COVID-19,” the researchers conclude in the article published online today in JAMA internal medicine .
The open trial was conducted in 20 public hospitals and one COVID-19 quarantine center in Malaysia between May 31 and October 25, 2021. It was led by Steven Chee Loon Lim, MRCP, Department of Medicine, Raja Permaisuri Bainun Hospital, Perak, Malaysia.
Of the 490 patients in the primary analysis, 52 of 241 patients (21.6%) in the ivermectin group and 43 of 249 patients (17.3%) in the control group progressed to severe disease (relative risk [RR], 1.25; 95% confidence interval [CI]0.87 – 1.80; P = 0.25). All of Malaysia’s major ethnic groups were well represented, the researchers write.
Participants (mean age 62.5% and 54.5% female) were randomized 1:1 to receive either a 5-day course of oral ivermectin (0.4 mg/kg body weight per day for 5 days) plus standard of care (n = 241) or standard of care alone (n = 249). The standard of care included symptomatic treatment and monitoring for early deterioration, based on clinical findings, laboratory tests, and chest imaging.
Secondary outcomes included rates of mechanical ventilationintensive care unit (ICU) admission, 28-day hospital mortality, and side effects.
In all secondary outcomes, there were no significant differences between the groups.
Mechanical ventilation occurred in four patients on the ivermectin protocol (1.7%) versus 10 patients in the control group (4.0%) (RR, 0.41; 95% CI, 0.13 – 1.30 ; P = 0.17); ICU admission occurred in six (2.4%) versus eight (3.2%) (RR, 0.78; 95% CI, 0.27, 2.20; P = 0.79); and in-hospital death at 28 days occurred in three (1.2%) versus 10 (4.0%) (RR, 0.31; 95% CI, 0.09-1.11; P = 0.09).
The most common adverse event was diarrheareported by 5.8% in the ivermectin group and 1.6% in the control group.
No difference by vaccination status
The researchers conducted a subgroup analysis to assess any differences in participants’ vaccination. They said the scan was “unremarkable.”
Just over half of the participants (51.8%) were fully vaccinated with two doses of COVID-19 vaccines. Among fully vaccinated patients, 17.7% in the ivermectin group and 9.2% in the control group developed severe disease (RR, 1.92; 95% CI, 0.99, 3.71; P = 0.06).
Ivermectin, an inexpensive and widely available antiparasitic drug, is prescribed to treat COVID-19, but has not been approved by the United States Food and Drug Administration for this purpose. Evidence for or against use is scarce.
The authors write, “Although some early clinical studies suggested the potential efficacy of ivermectin in the treatment and prevention of COVID-19, these studies had methodological weaknesses.
Lim and colleagues point out that their findings are consistent with those of IVERCOR-COVID19 trial, which found ivermectin ineffective in reducing the risk of hospitalization.
Previous randomized trials of ivermectin for COVID-19 patients that have included at least 400 patients have focused on outpatients.
In the current study, the authors note, patients were hospitalized, which allowed investigators to observe ivermectin administration with a high compliance rate. Additionally, the researchers used clearly defined criteria to determine progression to severe disease.
Limitations of the current study include that the open-label design could lead to underreporting of adverse events in the control group while overestimating the drug effects of ivermectin. The study was also not designed to assess the effects of ivermectin on COVID-19 mortality.
Marcia Frellick is a Chicago-based freelance journalist. She has already written for the Chicago Grandstand, Scientific News, and Nurse.com, and was editor at Chicago Sun-Timesthe Cincinnati Applicantand the St Cloud (Minnesota) hours. Follow her on Twitter at @mfrellick.