Since the last revision of this section of the Guidelines, the results of several randomized trials and retrospective cohort studies of ivermectin use in patients with COVID-19 have been published in peer-reviewed journals or have been made available as manuscripts ahead of peer review. Some clinical studies showed no benefits or worsening of disease after ivermectin use,21-24 whereas others reported shorter time to resolution of disease manifestations that were attributed to COVID-19,25-28 greater reduction in inflammatory marker levels,26,27 shorter time to viral clearance,21,26 or lower mortality rates in patients who received ivermectin than in patients who received comparator drugs or placebo.21,26,28
However, most of these studies had incomplete information and significant methodological limitations, which make it difficult to exclude common causes of bias. These limitations include:
The sample size of most of the trials was small.
Various doses and schedules of ivermectin were used.
Some of the randomized controlled trials were open-label studies in which neither the participants nor the investigators were blinded to the treatment arms.
Patients received various concomitant medications (e.g., doxycycline, hydroxychloroquine, azithromycin, zinc, corticosteroids) in addition to ivermectin or the comparator drug. This confounded the assessment of the efficacy or safety of ivermectin.
The severity of COVID-19 in the study participants was not always well described.
The study outcome measures were not always clearly defined.
Table 2c includes summaries of key studies. Because most of these studies have significant limitations, the Panel cannot draw definitive conclusions on the clinical efficacy of ivermectin for the treatment of COVID-19. 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.