The Food and Drug Administration issued an emergency use authorization Friday that will allow doctors to use Gilead Sciences’ drug remdesivir to treat patients who are hospitalized with serious cases of covid-19.

The limited approval allows the antiviral drug, which is administered intravenously, to be used to treat the disease in adults and children hospitalized with severe disease, which is defined as patients with low blood oxygen levels or needing oxygen therapy or a mechanical ventilator. Such an approval allows the agency to clear products for use without full data on their safety and efficacy.

Trump announced the Gilead authorization during a meeting in the Oval Office with FDA Commissioner Stephen Hahn and Gilead chief executive Daniel O’Day. The FDA then immediately released a statement detailing the decision.

The action comes two days after Anthony S. Fauci, the nation’s top infectious-disease expert, announced that trial data showed that the drug had a “clear-cut, significant, positive effect in diminishing the time to recovery.”

“That is really quite important,” said Fauci, director of the National Institute of Allergy and Infectious Diseases, which is overseeing a study of more than 1,000 patients in the United States and around the world.

O’Day, in a news release, said the authorization “opens the way for us to provide emergency use of remdesivir to more patients with severe symptoms of covid-19.” The company has already provided the drug to thousands of patients through clinical trials and its own compassionate use program.

Gilead said it would coordinate with the government to prioritize cities and hospitals most heavily impacted by coronavirus infections for distribution. Hospitals with intensive care units, which treat the most severely ill patients, will get the drug first, the company said.

Doctors will not use the drug on people with covid-19 who are at recuperating at home, said Paul Goepfert, an infectious disease doctor at the University of Alabama-Birmingham and a trial site investigator for the NIAID remdesivir study.

The drug was found in the trial to reduce hospital stays from 15 days to 11 days. The trial began in late February. Reaching the stage where it can be routinely provided to patients in a little over two months “has to be one of the fastest findings for this kind of drug development ever,'' Goepfert said.

A key consideration for its use will be drug availability. Gilead has said it plans to have enough doses for 140,000 people by the end of the month, a supply that could be extended if a finding in a separate Gilead trial holds up that said a five-day course of treatment might be as effective as a 10-day course.

Gilead has said it believes it can produce 1 million courses of treatment by the end of the year.

Possible side effects of remdesivir include increased levels of liver enzymes, which may be a sign of inflammation or damage to cells in the liver, and infusion-related reactions, which may include low blood pressure, nausea, vomiting, sweating and shivering.

The FDA is requiring that information about using remdesivir to treat covid-19 be made available to health-care providers and patients, including dosing instructions, potential side effects and drug interactions.

Mark Berman and Colby Itkowitz contributed to this report.