Fact Check: Are frontline workers taking hydroxychloroquine to prevent coronavirus?

Hydroxychloroquine is an anti-malarial drug often used to treat autoimmune diseases like lupus.

The President, who has consistently tested negative for coronavirus, appeared to suggest he was taking the drug as a way to prevent getting infected, something he claimed frontline health workers are doing as well.

"You look at doctors and nurses. A lot of them are taking it as a preventative," Trump said.

In early April, the Henry Ford Health System in Michigan launched the first large-scale study in the US of hydroxychloroquine's effectiveness in preventing or impeding Covid-19 in frontline workers. The 3,000 health care workers and first responders in southeast Michigan selected for the study each received unmarked vials with either a daily dose of hydroxychloroquine, a once-a-week dose, or a placebo.

After eight weeks, the three groups will be compared to see if the medication had any effect. Preliminary results are expected possibly in August.

The Duke Clinical Research Institute is leading a study to, in part, determine if hydroxychloroquine can successfully prevent coronavirus infections in health care workers with a high risk of infection.

The second part of the study is a randomized clinical trial which began last month and is currently examining almost 600 health care workers with 25 to 40 added each day. The participants are randomly divided into two groups, one will take hydroxychloroquine and the other a placebo to "examine whether hydroxychloroquine is effective in decreasing the rate of Covid-19 infection," according to a press release from the university.

Dr. Adrian Hernandez, professor of Medicine in Cardiology at Duke who started the program to study health care workers, told CNN the trial is expected to conclude this summer but could go into the fall.

When asked about the President's comments, Hernandez said that prior to these trials "there were likely health care workers before that were taking hydroxychloroquine."

However, Hernandez cautions against individuals who are not in these clinical trials taking the drug as a preventative measure against coronavirus. He recommended "that people participate in clinical trials for hydroxychloroquine, as opposed to taking it individually."

Hernandez added that taking the drug outside of a clinical trial in an attempt to prevent infection from coronavirus "like the President, is probably not the answer."

In March, the FDA granted emergency authorization for doctors to use hydroxychloroquine and chloroquine, a similar drug, in hospitals for a limited set of Covid-19 cases. Under the Emergency Use Authorization, the FDA authorized the drug's use as a potential treatment "only in hospitalized patients under careful heart monitoring."

Since then, several studies have tested the use of hydroxychloroquine to treat coronavirus. In mid-April, a French study determined that the drugs didn't help hospitalized coronavirus patients, and a study at US veterans hospitals found that coronavirus patients taking hydroxychloroquine were no less likely to need mechanical ventilation and had higher death rates compared to those who did not take the drug.

At the end of April, the FDA further cautioned against using hydroxychloroquine for Covid-19 "outside of the hospital setting or a clinical trial due to risk of heart rhythm problems."

The most recent guidelines from the FDA concluded that hydroxychloroquine has "not been shown to be safe and effective for treating or preventing Covid-19."

Although Trump does not qualify for the drug under the FDA's Emergency Use Authorization, the President's physician, Navy Cmdr. Sean Conley, said he "concluded the potential benefit from treatment outweighed the relative risks," according to a memo released Monday night.