Since the beginning of the COVID-19 pandemic, a number of drugs have been evaluated for “repurposing.” Repurposing refers to the practice of testing existing drugs for new therapeutic purposes. This has the advantage of reduced cost and distribution timelines, plus existing drugs have preexisting safety profiles and supply chains. Each of those characteristics are very helpful in the midst of a pandemic and in the case of COVID-19 where no treatment is available. 

Ivermectin, is one of the drugs being evaluated to see if it can be repurposed against COVID-19.  It has been shown to be effective against other viruses in the past. Moreover, it is widely used in low-middle and low-income countries, and is affordable.

Repurposing of Ivermectin for COVID-19 has mainly been evaluated for the treatment of COVID-19, rather than prevention of the virus. No studies have been published comparing the impact of the Ivermectin against the four notable circulating variants  (alpha, beta, gamma and delta) of COVID-19. 

Evaluation of Ivermectin for use in COVID-19 falls in three different categories. Each one is showing variable results.  1. In-vitro or test-tube studies which look at “effectiveness” of the drug in reducing virus load  2. Empirical evidence of Ivermectin against SARS-CoV-2. Some countries have mass Ivermectin administration programs for the prevention of parasites, and they report lower numbers of COVID-19 case counts. This indicates the potential of using Ivermectin for prevention of COVID-19. 3. In-vivo studies, which means testing on living organisms. These include clinical trials demonstrating conflicting results. The studies that did show a positive impact of Ivermectin were small, and used only in patients with mild COVID-19. In some cases effectiveness of Ivermectin was in combination with other drugs. Findings also suggested that for Ivermectin to be effective it would be at doses likely to be toxic. However, several clinical trials are being conducted to better understand the effectiveness of the drug against prevention and treatment of COVID-19. As of August 2021, according to ClinicalTrials.gov (the largest clinical trials database in the world) currently 75 studies are ongoing investigating the usefulness of ivermectin in COVID-19. Findings from such studies will be critical to determine if ivermectin can be used in the prevention and/or treatment of COVID-19 

In summary, the current evidence available on the use of ivermectin to treat COVID-19 patients is inconclusive. Health organizations including WHO recommends ivermectin only be used within clinical trials for COVID-19.

Since mid-2020, ivermectin has been discussed as a possible therapy to treat or prevent COVID-19 because it has shown some ability to act as an antiviral in non-human lab studies.

Some studies have shown promising results and have made headlines around the world, but not all studies have shown positive outcomes, and many are not rigorous enough to influence healthcare decisions. Health experts say more information is needed.

The U.S. National Institutes of Health (U.S. NIH) has noted that most of the studies on ivermectin have incomplete information and have limitations that impact how reliable the study may be. The U.S. NIH has further said that "results from adequately powered, well-designed, and well-conducted clinical trials are needed to provide further guidance on the role of ivermectin in the treatment of COVID-19."

Though ivermectin is approved by the United States Food and Drug Administration (U.S. FDA) for other illnesses, the U.S. FDA has stated that they have not approved ivermectin to treat or prevent viral infections, including COVID-19. Similarly, ivermectin has not been approved as a treatment for COVID-19 by the World Health Organization (WHO) or the European Medicinces Agency (EMA). The organizations recommend that ivermectin only be used for COVID-19 in clinical research studies.

The current U.S. National Institutes of Health recommendation states that "there are insufficient data for the COVID-19 Treatment Guidelines Panel (the Panel) to recommend either for or against the use of ivermectin for the treatment of COVID-19."  

The U.S. FDA has also noted that there have been multiple reports of people being hospitalized for taking ivermectin intended for horses. They have said that people should not use ivermectin intended for animals as a treatment for COVID-19.