Is there any truth that ivermectin prevents or lessens the severity of COVID-19?

Treatments Uncertainty and Misinformation

A. So far, we still have no evidence from well-designed randomized clinical trials (RCTs) that ivermectin is safe and effective for the prevention or treatment of COVID-19.

However, several RCTs are currently underway which will hopefully provide us with an answer to this important question.

➡️What is ivermectin?

Ivermectin (Iv) is a drug FDA-approved for the treatment of some parasitic worms in humans. It’s also FDA-approved for use in some animals to prevent heartworm and to treat parasites. When the human version of the drug has been used to treat parasitic infections, few side effects have been observed – when taken at the appropriate doses. But the version of Iv approved for use in animals has NOT been evaluated for safety in humans and can cause serious harm.

➡️How did it become so popular?

There’s currently no cure for COVID-19, but researchers have been scrambling to find treatments, especially those that are cheap and widely available. Iv is one drug that meets these criteria.

Public interest was first sparked after Australian researchers showed that Iv slowed the replication of SARS-CoV-2 in cells in a lab. Although promising, lab studies such as these are just the initial stages of drug development, and are not intended to inform treatment protocols in humans. Aside from this, the concentration of Iv that was required to slow replication was too high for use in humans.

This announcement was followed by the release of results from a study in humans which showed a reduction in mortality in critically ill hospitalized patients. But the study was later withdrawn after the investigators admitted that the data were fabricated. https://go.nature.com/3olyzRc

Since then, a variety of other study results have been released, largely from observational studies, which demonstrate some benefit of Iv for the prevention and treatment of COVID-19. Although this is promising, observational studies are not designed to show whether a particular drug is effective and safe. Well-designed RCTs are needed for this purpose.

There are several examples in the history of epidemiological research where treatments at first look promising in the lab and in observational studies, but prove to be either ineffective or harmful when evaluated in the context of well-designed RCTs. Hormone replacement therapy is a classic example whereby protective benefits were seen for heart disease in observational studies, but in an RCT, it was not only ineffective, but it appeared to *increase* the risk of breast cancer and heart disease. This is why we cannot rely on observational studies alone to inform treatment protocols in humans.

➡️ What do we know from RCTs?

To date, there are 41 registered RCT’s being conducted around the world (16 of which are the important Phase III trials) to evaluate the efficacy and safety of Iv. These studies are assessing a variety of endpoints including prevention of infection, severity, and mortality, and across the spectrum of disease severity (mild, moderate, and severe).

Results from a few of these studies have been reported, but most have not yet been peer-reviewed. Moreover, methodological limitations make it difficult to draw definitive conclusions so far.

Some examples:

1. In a study of 140 patients with mild, moderate, and severe COVID-19 in Iraq, results suggest that patients treated with Iv + doxycycline had faster mean time to “recovery” compared to patients treated with standard of care. Although this seems promising, the study was small, non-blinded (everyone knew what they were taking), and there was also no definition of “recovery” provided so it’s unclear what this really means.

2. In a larger RCT of 600 patients with mild, moderate, and severe COVID-19 in Egypt, the findings suggest that Iv + standard care led to a greater improvement in lab results and shorter hospital stay, compared to hydroxychloroquine (HCQ) + standard care. The limitations include questionable definitions about what constitutes recovery and improvement, and a lack of a placebo arm, so we don’t really know if Iv is more effective than standard care.

Neither study commented on the safety of the treatment regimens, so we also don’t yet know about the safety profile of Iv in patients with COVID-19. But the good news is that larger, better designed RCTs are in the pipeline.

And we’ll be here to break them down for you as the results roll out!


There’s still no solid evidence from well-designed studies that Iv is safe and effective to prevent or treat COVID-19, but stronger studies are forthcoming. Because there are so few cheap and accessible options to treat COVID-19, it’s understandable why much of the world is pinning its hopes on this medication. But it’s also important to recognize that policy decisions around treatment protocols should be based on sound science.

Self-medication with Iv should be avoided. Moreover, Iv products intended for animals have not been tested in humans, do not use dosages appropriate for humans, and include other ingredients not meant for use in humans. Don’t take your puppy’s ivermectin! And as always, consult your doctor about treatments for Covid-19.


For an overview of all the COVID-19 treatments under study

List of all registered RCTs evaluating ivermectin

FDA guidance on ivermectin





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