Ivermectin and zinc for viruses?

The short version: the evidence for ivermectin plus zinc against viruses is weak, uncontrolled, and does not meet the burden of proof for a healthy person.

The best study you have on ivermectin for a virus is a retrospective look at 338 COVID-19 patients in the Philippines who all got the drug [1]. There was no control group that did not get ivermectin. The study found that 95.6% recovered, but without a comparison group you cannot know if they would have recovered just as fast without it. The same study did find that zinc, when added to ivermectin, had a statistically significant effect on recovery [1]. That is a signal worth noting, but it comes from the same uncontrolled design.

A separate retrospective series of 320 high-risk outpatients given a multidrug cocktail that included ivermectin and zinc reported only 1.9% hospitalized and 0.3% died [3]. Again, no control group. The authors themselves note the limitation: the patients were selected by clinician judgment, so the low event rate could reflect who was chosen for treatment, not the treatment itself [3].

For the common cold, a small randomized trial of high-dose vitamin C plus zinc found a modest reduction in runny nose duration that reached statistical significance only when the two small studies were pooled [2]. The individual studies did not reach significance [2]. That is a weak signal for a minor outcome.

What is missing from this retrieval is more important than what is present. There is no randomized, placebo-controlled trial of ivermectin plus zinc for any viral infection that measures hard outcomes like hospitalization or death. The studies here are all observational, all uncontrolled, and all from early pandemic settings where background recovery rates were high. The burden of proof has not been met.

My call: the evidence does not support using ivermectin plus zinc as a treatment for viral infections in a healthy person. Confidence: low.