Does Ivermectin help treat or prevent COVID-19?

Treatments Uncertainty and Misinformation

A: We don’t know for sure, but the best available existing data does not support its use to treat or prevent COVID-19. Lots of studies are ongoing and may give us a clearer answer over time.

Ivermectin is a medicine that is used to treat infections from parasites (like worms) in people and animals. People got really excited about ivermectin early in the pandemic because studies showed that ivermectin could inhibit the replication of the virus in lab samples. Everyone was hoping maybe it would work in people too! That meant a lot of folks started taking ivermectin to prevent and treat COVID-19, especially in parts of the world where ivermectin is available over the counter without a prescription.

Unfortunately, and despite being one of the most studied drug interventions for COVID-19, we don’t have very good data about the safety or efficacy of ivermectin for COVID-19 prevention or treatment. Why, you ask? Because a lot of the studies were poorly done, had too few people in them, didn’t randomize, or did too many interventions at one time. One very large and frequently cited study preprint from Elgazzar and colleagues was actually retracted by Research Square for concerns over plagiarism and data manipulation (that is a huge deal). In short, there is a lot of data out there and much of it is lousy.

Our best available evidence comes from a systematic review conducted by the Cochrane Collaboration (linked below). Systematic reviews are often the very top of the evidence pyramid because they provide a very structured, transparent method to look at a lot of data at once to answer a question. Good systematic reviews look at all the available data out there but only include information that really does answer the question and uses reliable methods. Systematic reviews tell you up front what studies are included, and which ones are not (and why). This prevents something called “cherry picking,” where people only pick data that supports the conclusion they want to draw and leaves out anything that might contradict that. Using various statistical methods, systematic reviews can then put together data from a bunch of different trials to come up with an answer to the question. (Excited about systematic reviews? Cochrane has a useful video talking about systematic reviews.

This systematic review wanted to know if ivermectin reduced death, illness, and length of infection in people with COVID-19 and if it prevented infection in the first place. They only included randomized controlled trials and excluded trials that did not answer the question, had a high risk of bias, or compared ivermectin to something that doesn’t work (like hydroxychloroquine). Out of over 300 trials, only 14 studies met eligibility criteria with a total 1678 participants and compared treatment with ivermectin to no treatment, placebo, or typical treatments (As I said, a lot of the studies out there are junk). There were 9 studies that had people with moderate illness in the hospital and 4 that had people with mild COVID-19 getting treatment at home. All the studies used different doses and duration of treatment, making comparisons super hard. Only 1 study looked at ivermectin to prevent COVID-19.

So, what does this systematic review show for ivermectin?

➡For people in the hospital, ivermectin compared with placebo or typical care doesn’t seem to make a real difference in improving a patient’s condition 28 days after treatment or how long someone stays in the hospital.

➡For both people treated in the hospital and at home, it is unclear if ivermectin reduces or increases the risk of death, the need for oxygen, or COVID-19 symptoms. Can’t tell if it helps or hurts or does nothing at all.

➡There was no clear improvement demonstrated for people with COVID-19 infections.

➡Only one small study looked at prevention of COVID-19. Because no one died in the study (the study was too small), it could not tell us if ivermectin prevented death. The study only reported results for development of symptoms but did not report results for confirmed cases of COVID-19 infection. Ultimately, this study wasn’t helpful.

➡All the studies were small and few were high quality. More and better studies are needed.

For now, there is not convincing data to use ivermectin for treatment or prevention. The good news is that many studies are ongoing and looking to answer this question.

Currently, the FDA and WHO recommend AGAINST using ivermectin outside of clinical trials. Ivermectin has NOT been approved for use in COVID-19. There are some safety concerns to taking ivermectin as well. People can have side effects like dizziness, itching, nausea, and diarrhea. Too much ivermectin can cause low blood pressure, balance problems, seizures, and even death. Ivermectin can interact with other medications people take, too, creating all sorts of problems.

One last thing: NEVER take ivermectin intended for animals. Animal products are different than ones prescribed to people. It is usually a much higher dose and can contain other ingredients that are not used for people.

If you have questions about ivermectin and use in COVID-19, talk with your healthcare team.

Stay safe. Stay sane. Enjoy reading well done systematic reviews.

Those Nerdy Girls


Nature article discussing the retraction of the Elgazzar preprint

Cochrane Systematic Review

WHO Recommendation against Ivermectin

FDA statement against Ivermectin

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