Claims that Ivermectin causes infertility in men that recently spread online were based on a flawed 2011 study from Nigeria that included only 37 subjects.
Recent news articles and memes made the infertility claim based on a 2011 study conducted in Nigeria. The study focused on Ivermectin as a treatment for river blindness, a parasitic infection endemic to Africa and one of the conditions that the drug is approved to treat in humans. However, infertility is not a known side effect of Ivermectin, according to the Food and Drug Administration (FDA).
The infertility claim spread quickly due to Ivermectin increasingly being used by some as an unapproved, and likely ineffective, treatment for COVID-19. The 85 percent figure did not come from the Nigerian study itself, but rather from a different study that it references, although no record of the study could be found in the journal cited. The Nigerian study, which was conducted without a control group, also tested the drug’s possible effects on male fertility.
Out of the 385 men who were originally included in the Nigerian study, data from only 37 was ultimately investigated, with the remaining men excluded because their sperm counts that were already too low. Of the 37 men who had high enough sperm counts to be studied, it was found that their fertility was negatively impacted, although the effect was small in some subjects, and it was not clear whether it was a temporary effect.
There is little reason to believe that Ivermectin causes infertility in people. The Nigerian study was conducted on a small number of subjects, and questions have been raised over the methodology of the study and the peer-review process of the journal it was published in. Some research has suggested that the drug impacts the fertility of farm animals, but animal research often does not apply to humans.
There is also little reason to believe recent claims that Ivermectin is a “cure” or useful treatment for COVID-19. While a number of small studies have suggested that Ivermectin may have potential as a COVID-19 treatment, many other studies have shown that there is no benefit or have been inconclusive. Some of the studies that showed positive outcomes have been criticized by experts for poor design and other errors.
One large meta-analysis in July that was touted as evidence of Ivermectin’s effectiveness against COVID-19 was quickly retracted when it was discovered that fraudulent data was used. Without the fraudulent data, the analysis found that Ivermectin did not impact the survival of COVID-19 patients. Additional research is ongoing, but the available evidence does not support the assertion that Ivermectin is an effective treatment for COVID-19.
Although the drug is generally well-tolerated when used for approved conditions and at the appropriate doses, the FDA said last week it had “received multiple reports of patients who have required medical attention, including hospitalization, after self-medicating with ivermectin intended for livestock.”
The FDA warned consumers who may baselessly believe that Ivermectin is a COVID-19 cure that the drug should not be used off-label because it can cause a host of unpleasant side effects aside from infertility, even if it is not sourced from veterinary medicine.
“Even the levels of ivermectin for approved human uses can interact with other medications, like blood-thinners,” the FDA notice reads. “You can also overdose on ivermectin, which can cause nausea, vomiting, diarrhea, hypotension (low blood pressure), allergic reactions (itching and hives), dizziness, ataxia (problems with balance), seizures, coma and even death.”
Newsweek reached out to the FDA for comment.
