The Lancet: Comment – Long-term consequences of the misuse of ivermectin data


Long-term consequences of the misuse of ivermectin data

Published:October 18, 2021

Ivermectin is an oral anti-infective medicine that is integral to neglected tropical disease programmes. It is safe and effective for the treatment and control of lymphatic filariasis, scabies, and onchocerciasis, sometimes as part of a mass drug administration, as recognised in the WHO road map for neglected tropical diseases 2021–30.1 The WHO essential medicines list provides recommendations for minimum medicine needs for a basic health-care system, which includes ivermectin as an anthelmintic, antifilarial, and antiectoparasitic treatment.2

There has been a groundswell of opinion across several countries that ivermectin might be useful in reducing the symptoms of and mortality due to COVID-19, with many citing meta-analyses that infer positive effects;3 however, these conclusions appear to be unreliable. On March 31, 2021, WHO advised that ivermectin should only be used within clinical trials and not as part of routine clinical practice.4 This advice was followed by the manufacturer, Merck, that stated on Feb 4, 2021, that there is “no meaningful evidence for clinical activity or clinical efficacy in patients with COVID-19 disease”.5 Despite this, ivermectin is being routinely used in some Latin American settings amid recommendations from some governments and health professionals.6

In July, 2021, a number of scientists reviewed and reported detailed clinical trial data for use of ivermectin for COVID-19.7 Their commentaries, which were not peer-reviewed, highlighted extensive inconsistencies within the trial data. They also found that the ivermectin trials with inconsistent data were pivotal to the positive conclusions in peer-reviewed meta-analyses. A July, 2021, Cochrane Review assessed the evidence base for ivermectin use in prevention of COVID-19, and treatment of individuals in inpatient and outpatient settings.8 Their conclusion was one of uncertainty, highlighting that the included studies were small, with few considered to be of high quality.

As the global health community works to control the COVID-19 pandemic, is the future use and reputation of ivermectin at risk?

Sustained campaigns of misinformation can affect trust and affect public health and population behaviour.

Sustained misinformation can lead to diversion of limited health-care and government resources to addressing rumours rather than making genuine public heath progress. Proactive health promotion and education is needed right now to ensure that locally trusted actors and communicators (including, but not limited to, health-care workers) are aware of the uncertainty around the ivermectin evidence base for managing COVID-19, and that it remains a vital medicine for managing neglected tropical disease.

To meet the ambitious 2030 targets of the WHO neglected tropical disease roadmap,1 reducing stigma around neglected tropical diseases and prevalence of misinformation will be important. In lower-income settings, organisations have spent years building trust between health services and their populations to ensure high acceptance and uptake of population health campaigns. If that trust is eroded because of negative local perceptions around the use of ivermectin, then achievement of national and global neglected tropical disease targets might be hindered, and ultimately vulnerable populations would suffer.

JAC and JM’s institution receives financial support from National Institutes for Health Research Global Health Unit for Neglected Tropical Diseases. All other authors declare no competing interests. All authors contributed equally.


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