The NIH Treatment Guidelines Panel recently changed ivermectin from firmly “against” to the neutral “neither for nor against” when it comes to mild COVID-19 treatment. Ivermectin, developed in 1975, led to the eradication of numerous parasitic diseases and earned the 2015 Nobel Prize for Physiology or Medicine for its discoverers, Dr. William Campbell and Dr. Ōmura Satoshi. It is considered safe and cheap but like another famous drug, the malaria treatment hydroxychloroquine, its claims about COVID-19 are more anecdote than science. In vitro studies are fine exploratory efforts but were only shown to do anything positive at doses far exceeding realistic human levels, unworkable for mild COVID-19. An unsubstantiated trial in humans placed the claims in the dubious camp of other debunked claims like those of the Rational Vaccines (RVx) herpes prevention, but more recently NIH said they would give ivermectin a new look if better studies arrived.

Like with hydroxychloroquine, some countries began using ivermectin despite lacking evidence on its efficacy in treating or preventing infection. A small pilot study may add evidence that a meta-analysis cannot.

The research team gave one single dose of ivermectin or placebo to 24 patients with confirmed infection and mild symptoms, within the first 72 hours after the first symptoms started. Nasal swabs and blood samples were taken at the moment of enrollment and 1, 2 and/or 3 weeks after treatment. 

SAINT Research team.

Seven days after treatments, no difference was observed in the percentage of PCR-positive patients (100% of patients were positive in both groups). However, the mean viral load in the ivermectin-treated group was lower (around 3x lower at 4 days and up to 18x lower at 7 days post-treatment), although the difference was not statistically significant. Treated patients also showed a reduced duration of certain symptoms (of 50% for loss of smell and taste and of 30% for cough). All patients developed virus-specific IgG but, again, the mean level of antibodies in the treated group was lower than in the placebo group. 

There was no effect on duration of symptoms or makers associated with inflammation so ivermectin may act through mechanisms that do not involve a possible anti-inflammatory effect. The authors believe it could be interfering with viral entry in the cells, as suggested by another study using hamsters. As always, caution is warranted about a small pilot study just like with epidemiology or animal models.