Ivermectin under scrutiny: a systematic review and meta-analysis of efficacy and possible sources of controversies in COVID-19 patients

BACKGROUND: We conducted a systematic review and meta-analysis to evaluate the efficacy of ivermectin for COVID-19 patients based on current peer-reviewed RCTs and to address disputes over the existing evidence. METHODS: MEDLINE (Pubmed), Scopus, Web of Science, Cochrane library, Google scholar and Clinicaltrials.gov were searched for RCTs assessing the efficacy of Ivermectin up to 20 February 2022. A systematic review and meta-analysis of studies was performed based on the PRISMA 2020 statement criteria. RESULTS: 19 and 17 studies were included in this systematic review and meta-analysis, respectively. There was no significant difference in progression to severe disease (log OR − 0.27 [95% CI − 0.61 to 0.08], I2 = 42.29%), negative RT-PCR (log OR 0.25 [95% CI − 0.18–0.68], I2 = 58.73%), recovery (log OR 0.11 [95% CI − 0.22–0.45], I2 = 13.84%), duration of hospitalization (SMD − 0.40 [95% CI − 0.85–0.06], I2 = 88.90%), time to negative RT-PCR (SMD − 0.36 [95% CI − 0.89–0.17], I2 = 46.2%), and viral load (SMD -0.17 [95% CI -0.45 to 0.12], I^2 = 0%). It is worth noting that, based on low-certainty evidence, ivermectin may possibly reduce mortality (log OR − 0.67 [95% CI − 1.20 to − 0.13], I2 = 28.96%). However, studies with a higher risk of bias were more likely to indicate positive effects on the efficacy of this drug, according to our subgroup analyses based on study quality. CONCLUSION: Ivermectin did not have any significant effect on outcomes of COVID-19 patients and as WHO recommends, use of ivermectin should be limited to clinical trials. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12985-022-01829-8.