The anti-parasitic drug ivermectin, despite lacking strong research to support it, has surged in popularity as an “alternate” treatment for COVID-19.
A study published on Wednesday compared more than 1,300 people infected with the coronavirus in Brazil who received ivermectin or a placebo, and effectively ruled out the drug as a treatment for the virus.
The researchers shared their results in August during an online presentation hosted by the National Institutes of Health, bu the full data wasn’t published until now in the New England Journal of Medicine.
Ivermectin has been widely used to treat parasitic infections. Early in the pandemic, researchers were trying thousands of old drugs against COVID-19, and initial labarotry experiments on cells suggested that ivermectin might block the coronavirus.
Skeptics pointed out that the experiments worked due to extremely high concentrations of the drug, much higher than safe levels for people. Despite the lack of strong evidence, some doctors began prescribing ivermectin for COVID-19, ignoring a warning from the Food and Drug Administration that it was not approved for such use.
Small clinical trials aroudn the world were conducted using the drug to attempt to treat the coronavirus. Andrew Hill, a virologist at the University of Liverpool in England reviewed the results of 23 trials and concluded that ivermectin appeared to lower the risk of death from COVID-19 signifiantly in December 2020.
Ivermectin’s popularity continued to grow in the second year of the pandemic. The podcaster Joe Rogan promoted it on his shows. Insurance companies spent $2.4 million paying for ivermectin treatments in just one week of August.
However, not long after Dr. Hill’s review, reports surfaced that many of the studies he included in his analysis were fundamentally flawed, with one even alleged to be fraudulent. Dr. Hill retracted his original study, publishing a new one in January.
In his second review, Dr. Hill focused on the studies least likely to be biased. In that stricter survey, the benefit of the drug vanished.
Still, even the most reputable studies on the drug’s connection to the virus were small, with the highest having a few hundred volunteers. Small studies can be vulnerable to statistical errors that may suggest positive effects were none exist. Larger studies were underway, and those promised to be more reliable.
In Brazil, in June 2020, researchers set up a clinical trial called TOGETHER to test COVID-19 patients with a number of widely used drugs, including ivermectin. The treatments were double-blinded, meaning that neither the patients nor their medical staff knew whether they received a COVID-19 treatment drug or a placebo.
In one round, researchers found promising evidence that an antidepressant drug named fluvoxamine reduced hospitalizations by one-third. They published their results in the Lancet Global Health in October.
The TOGETHER team reported its ivermectin data in a new study published Wednesday. T679 patients were provided the drug over the course of three days.
Taking ivermectin did not reduce hospitalization.
The researchers focused on different groups seperately to see if they experiences different benefits. For example, if ivermectin worked earlier in infection better. However, the volunteers who took ivermectin in the first three days after a positive coronavirus test turned out to have worse outcomes than those in the placebo group.
Dr. Hill was impressed with the results, praising their “high-quality, placebo-controlled trial.” He also faulted the New England Journal of Medicine for taking months to publish their results.
Dr. Hill then ran his analysis again, this time adding the TOGETHER trial’s data. With over 5,000 people, he once again saw no benefit from ivermectin.
There are still some ongoing randomized trials of ivermectin with thousands of volunteers that haven’t shared their results yet. A part of the NIH called the National Center for Advancing Translational Sciences has been running a closely watched trial of overmectin for over a year. It hasn’t shared its results yet.