The controversial coronavirus drug that a Hasidic doctor has been using to treat hundreds of people with moderate symptoms in upstate N.Y. is also being tried by doctors in at least three other states, and New York health officials have started using it to treat critically ill patients in hospitals.

The expansion in the use of the drug, the anti-malarial hydroxychloroquine, comes despite concern that its effectiveness in treating Covid-19 has not been tested in a controlled clinical study, and that demand for it could cause shortages that prevent access by people with other diseases who need it. Its embrace by the Trump administration and conservative political commentators has only intensified the debate over its use.

The Washington Post reported on Thursday that Dr. Vladimir Zelenko, who discussed his use of the drug in combination with antibiotics in a Forward article on Tuesday, had been contacted by President Trump’s new chief of staff, Rep. Mark Meadows. A person close to Meadows told the Post that the two had been in touch and White House experts were evaluating Zelenko’s protocol.

Trump had previous described the drug as a possible “gift from God” in the fight against coronavirus. Zelenko, whose practice is mostly ultra-Orthodox patients near the Orange County, N.Y., village of Kiryas Joel, told the Forward he had given the drug regimen to more than 500 moderately ill people and no more than a handful needed hospitalization.

The Post article said that in New York, the epicenter of the outbreak in the United States with infections topping 30,000, state officials are now rushing to distribute the combination of hydroxychloroquine and antibiotics to those seriously ill with coronavirus and to study the results. A campaign to authorize the use of drugs that way would have normally taken nine months, but took only three days, the article said.

Yet even as such officials and some doctors rushed to deliver the drug cocktail to patients, concerns persist about the lack of solid science regarding its effectiveness — and shortages. Top health officials have dismissed as “anecdotal” reports of success by Zelenko and others.

Zelenko said in an interview earlier this week that his clinic near the Hasidic village of Kiryas Joel, in Orange County, N.Y., had given the drug cocktail to more than 500 patients, and none required hospitalization.

Dr. David Sullivan, an infectious-disease expert at Johns Hopkins University who studies malaria, and is familiar with hydroxychloroquine, said the drug might have a marginal benefit in fighting coronavirus, and could prevent some hospitalizations. But, he said, if it was a silver bullet like penicillin is for the strep bacteria, we would know by now.

And if New York State is counting on the drug, Nevada’s government is doing the exact opposite, the Post said: It’s banning prescriptions of the drug until more is known about how it works against coronavirus.

People with other illnesses, like lupus, definitely need hydroxychloroquine and are starting to have trouble getting it, due to the run on it triggered by interest in its coronavirus application.

“The data is limited,” said Dr. Rosy Joseph, a New Jersey internist who says she has given more than 50 patients with Covid-19 symptoms hydroxychloroquine, all on an outpatient basis. “But at this point there’s not much else that we can try.”

Joseph is a kidney specialist at Hackensack University Medical Center, and is familiar with hydroxychloroquine because she uses it to treat patients who have the auto-immune disease lupus. She said that initially she was only giving the drug to people who have high-risk factors for death from Covid-19, but is now giving it to anyone with moderate symptoms, because of the high rates of hospitalization of people under 50 with the disease in the U.S.

Joseph also said she has been in touch with a Crown Heights doctor treating hundreds of patients with the drug. A doctor at a veterans’ home in Oregon said he is treating 8 high-risk patients who tested positive for the virus with it.

“I’m seeing improvement within 24 to 48 hours but I can’t tell you whether that’s the course of the disease — I don’t have a control arm — or whether it’s the effect of the drug,” the doctor, Robert Richardson, said in an interview.

Indeed, one study of 30 patients from China recently concluded that giving the drug to Covid-19 patients provided no discernible benefit.

Since Zelenko, Joseph and the other doctors are prescribing the drug outside of a controlled study, it is impossible to have statistical data that indicates whether its use actually prevented people from going to the hospital.

That kind of information could soon come, from the study about to start in New York and from a clinical study being run by Dr. David Boulware, an infectious-disease expert at the University of Minnesota. His study is trying to determine if the drug can limit symptoms for people who have been closely exposed to the virus, and if it can prevent hospitalization among people who actually test positive for the virus.

“There’s a risk-benefit for everything,” Boulware said. “But if you don’t know that it works, then there’s a risk, but what’s the benefit?”

Ari Feldman is a staff writer at the Forward. Contact him at feldman@forward.com or follow him on Twitter @aefeldman