(CNN) President Donald Trump has twice tested negative for the coronavirus, but during a briefing at the White House on Saturday, he said he "may take" the drug hydroxychloroquine against Covid-19. He suggested it has protective effects against the novel coronavirus, although researchers say there's no evidence of that.
"I think people should [take hydroxychloroquine]," he told reporters at a White House press briefing on Saturday. "If it were me, in fact, I might do it anyway. I may take it ... I have to ask my doctors about that. But I may take it."
Trump said lupus patients -- who are often treated with hydroxychloroquine -- seem less likely to contract Covid-19, and that "there's a rumor out there" and "there's a study out."
"Maybe it's true, maybe it's not. Why don't you investigate that?" he asked.
At the briefing, Dr. Anthony Fauci, the nation's top infectious disease expert, said, "We don't have any definitive information to be able to make any comment." He also said the relationship between lupus and Covid-19 is currently under investigation.
Experts do not suggest taking hydroxychloroquine as a preventive for Covid-19 because there is no evidence yet to suggest it protects against contracting the virus.
"We need evidence and science, not fear and anxiety to drive these decisions," said Dr. Saira Sheikh, director of the University of North Carolina Rheumatology Lupus Clinic and director of the Clinical Trials Research Program at The University of North Carolina at Chapel Hill Thurston Arthritis Research Center.
Hydroxychloroquine may also cause side effects and could be dangerous to otherwise healthy individuals if used incorrectly without the appropriate indication, prescription or monitoring, she said in an email to CNN.
Hydroxychloroquine is generally considered safe but side effects do happen, according to Dr. Jeffrey Sparks, a rheumatologist at Brigham and Women's Hospital and Harvard Medical School.
Side effects include changes in heart rhythm, which can cause sudden death, severe rashes and dangerous allergic reactions, Sparks said.
"I think it's too early to really endorse its wide use," he said. "I would not endorse it myself."
As a treatment for Covid-19, there also hasn't been much research on hydroxychloroquine. There are no randomized controlled trials and most data on patients has been extrapolated from small, single center studies, according to UNC's Sheikh.
While there's no definitive proof at this point that the drug works for Covid-19 patients, doctors have seen the impact of the White House endorsement of the drug for use against the coronavirus.
Sparks said some of his rheumatologic patients have had to look for hydroxychloroquine in different states due to shortages, for example.
"The impact of President Trump's comments will be detrimental to the subset of patients that require hydroxychloroquine to control their disease," said Dr. Alfred Kim, an assistant professor of medicine and rheumatology at Washington University School of Medicine in St. Louis.
"The patient population that is the most vulnerable are the lupus patients because hydroxychloroquine is the only drug known to prolong survival of these patients," he said.
At the press briefing, Trump also referenced a study that he said showed lupus patients who were taking hydroxychloroquine were protected against Covid-19, which puzzled experts.
"That statement from Trump was a surprise," Kim said.
CNN has reached out to the White House regarding the lupus study to which Trump had referenced but has not received a response at the time of publication.
There are no published studies specifically looking at the relationship between lupus patients on hydroxychloroquine and Covid-19, according to Kim.
The one thing Kim said he found was a sentence in the introduction of a non-peer-reviewed study from researchers in Wuhan, China, who said they had no lupus patients infected with Covid-19 in their follow-up surveys. They did not indicate whether these lupus patients were included in the original study, which looked at the efficacy of hydroxychloroquine treatment for Covid-19.
"Typically through the peer review process, a line like that would be expunged," said Kim. He added there was no data in the article to back up the sentence and that the study wasn't intended to evaluate lupus and Covid-19, just hydroxychloroquine as a treatment for Covid-19 generally.
In contrast, there have been patients with lupus and other rheumatologic conditions on hydroxychloroquine diagnosed with Covid-19, according to the COVID-19 Global Rheumatology Alliance.
The alliance keeps a registry of rheumatologic patients diagnosed with Covid-19 from around the world. Patients from every continent except Antarctica are represented in this database, according to Brigham and Women's Hospital's Sparks.
Both Kim and Sparks are members of the alliance and hope physicians will add their patients to this registry to help understand how rheumatologic conditions such as lupus -- which require drugs that may dampen immune systems and autoimmune diseases -- are affected by Covid-19.
If anything, because lupus patients are on immunosuppressive drugs, they might be at increased risk of Covid-19 infection compared to the general population, Sparks said.
Kim said he's concerned about Trump's comments on hydroxychloroquine.
"We hope that [hydroxychloroquine] ends up being effective," he said. "But at this time, the risk benefit may actually backfire and harm more people than help."