Low-Dose Ivermectin Found Ineffective with High-Risk COVID-19 Patients

The peer-reviewed JAMA Network published a study today that found in a randomized clinical trial of high-risk patients with mild to moderate COVID-19, ivermectin treatment during early illness did not prevent progression to severe disease. 

This study’s findings, published on February 18, 2022, do not support the use of low-dose ivermectin for COVID-19 patients at risk.

These 500 randomized COVID-19 patients received Ivermectin 0.4mg/kg of body weight/day for 5 days.

‘Our findings are consistent with the results of the IVERCOR-COVID19 trial (July 2021), which found that ivermectin was ineffective in reducing the risk of hospitalization.’

Prior randomized clinical trials of ivermectin treatment for patients with COVID-19 and 400 or more patients enrolled focused on outpatients.

In contrast, 'the patients in our phase 3 clinical trial were hospitalized, which permitted the observed administration of ivermectin with a high adherence rate.'

Furthermore, ‘we used clearly defined criteria for ascertaining progression to severe disease.’

Before the trial started, the case fatality rate in Malaysia from COVID-19 was about 1%, a rate too low for mortality to be the primary endpoint in this study. 

Even in a high-risk cohort, there were 13 deaths (2.7%). 

The pharmacokinetics of ivermectin for treating COVID-19 has been a contentious issue. 

The plasma inhibitory concentrations of ivermectin for SARS-CoV-2 are high; thus, establishing an effective ivermectin dose regimen without causing toxic effects in patients has been difficult.

In previous studies, dose regimens that produced favorable results against COVID-19 ranged from a 0.2-mg/kg single dose to 0.6 mg/kg/d for five days. A concentration-dependent antiviral effect was demonstrated by Krolewiecki et al. However, the notably higher incidence of adverse events in the ivermectin study cohort raises concerns about the use of ivermectin without medical supervision, added these researchers.

This phase 3 study has limitations.

• First, the open-label trial design might contribute to the underreporting of adverse events in the control group while overestimating the drug effects of ivermectin.
• Second, our study was not designed to assess the effects of ivermectin on mortality from COVID-19. 
• Finally, the generalizability of our findings may be limited by the older (62 yrs. average) study population.

These findings notwithstanding, ivermectin is widely prescribed for COVID-19, contrary to the World Health Organization and U.S. FDA’s recommendations.

The U.S. FDA continues approving ivermectin tablets to treat people with intestinal strongyloidiasis and onchocerciasis, two conditions caused by parasitic worms.

In addition, some topical forms of Ivermectin are approved to treat external parasites like head lice and for skin conditions such as rosacea. 

A separate version of Ivermectin is used in veterinary applications.

The FDA has recently authorized two oral antivirals to treat early COVID-19 diagnosed patients, and other ‘pills’ are under review.  

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