Washington state health officials used an unapproved antiviral drug developed to fight Ebola to treat the first patient with novel coronavirus in the U.S., they announced after publishing their treatment course on Friday.

In a paper detailing the patient’s care published on Friday in the New England Journal of Medicine, health officials noted that the patient from Snohomish County with novel coronavirus (2019-nCoV) had conditions that worsened after he tested positive for the virus and was admitted to a hospital.

On Jan. 20, the 35-year-old man was admitted to Providence Regional Medical Center in Everett to be monitored at their airborne-isolation unit. He presented a dry cough and had reported nausea and vomiting for two days. His vital signs were stable, however, and he continued to present cold-like symptoms for the next few days. Hospital staff monitored him, and chest X-rays initially showed no abnormalities. That changed on the fifth day of his hospitalization, when evidence of pneumonia was apparent in his left lung.

The patient’s respiratory status also changed that day, and he was administered supplemental oxygen. The pneumonia-like symptoms intensified on the sixth day, with evidence found in both lungs. The patient continued to test positive for the novel coronavirus and had fevers, leading doctors to pursue the use of remdesivir, which was developed by Gilead Sciences as an antiviral Ebola treatment that ultimately was not as successful as monoclonal antibody treatments.

Remdesivir has not been approved for use by the Food and Drug Administration, although doctors can pursue “compassionate use” of a drug in the event of a serious health condition where the benefits outweigh the risks. The patient consented to this treatment.

“To my knowledge, this is the first reported case in the world where this drug has been used in a human application against this virus,” Dr. Jay Cook, chief medical officer at Providence Regional Medical Center, said in a press call Friday.

The antiviral therapy was administered once on the patient’s seventh day in the hospital, and no adverse events were reported afterward. The patient’s condition improved and staff discontinued supplemental oxygen by the eighth day. His lungs were also clearer by then as well. As of Thursday, the patient remained hospitalized. On Friday, Cook declined to give details of the discharge plan or date due to the patient’s privacy.

Health officials hope that the Washington state case and treatment can be used to help fight the virus nationally, and globally as well.

“This is a drug that is not available to the general public, it is released on limited use and really was developed for the Ebola crisis,” said Dr. Scott Lindquist, Washington state epidemiologist.

While the U.S. is the first to use remdesivir, other countries could potentially follow suit.

“We do know that the manufacturer of this product is trying to work with China to provide this overseas,” Lindquist said on Friday.

The report on the Washington man’s treatment cautions that “randomized controlled trials are needed to determine the safety and efficacy of remdesivir and other investigational agents for treatment of patients with 2019-nCoV infection.”

The World Health Organization declared the outbreak a public health emergency on Thursday.

So far, little is known about what animal the virus originated from and how it is transmitted, although Washington state health researchers have made some headway. The Snohomish County man’s case further supports evidence that the virus can be passed from person to person. Samples from his upper respiratory tract tested positive for the virus on the fourth and seventh days he was in the hospital, and tests also detected the virus in some of the patient’s stool samples on the seventh day.

The Snohomish County man was the first of now seven confirmed cases of 2019-nCoV in the U.S. across four states. In Washington, 21 people have been tested for the virus, and so far 14 tests have come back negative. Six tests are still pending with the CDC labs in Atlanta. Beyond cases being tested, 65 close contacts are being monitored in the state. These are people who came within 6 feet of the man with the virus for longer than 10 minutes.

While health officials stress that the likelihood of the novel coronavirus spreading in the U.S. and Washington is relatively low, anyone who has traveled from Wuhan, China, should monitor their symptoms and contact their health care provider if they experience fever, cough or shortness of breath. Symptoms can present themselves in as few as two days or as long as two weeks after exposure, according to the CDC. Risk to the general public is still low, however.

The CDC is recommending that U.S. travelers avoid all nonessential travel to China, and the U.S. State Department issued a “do not travel” advisory to China on Friday, citing the novel coronavirus outbreak. Wuhan, a city of 11 million people in central China, is on lockdown with no flights or trains entering or leaving the city. As of Jan. 23, all flights were canceled out of Wuhan.

For travelers returning to the U.S. from China, flight are being directed to seven of the 20 airports in the nation that have CDC quarantine stations and enhanced screening, including Seattle-Tacoma International Airport.

CDC employees are contacting all passengers arriving from China with questionnaires for self-identification, and public health staff are monitoring passengers for signs of illness when they arrive in Seattle. Sea-Tac has never had any direct flights to Wuhan.