The report on Tuesday of a powerful treatment for the new coronavirus brought skepticism along with optimism among U.S. doctors, who said the recent withdrawal of an influential COVID-19 study left them wanting to see more data.

Global pressure to find a cure or vaccine has accelerated the process of reporting coronavirus study results, feeding confusion over whether therapies have been proven effective. One influential COVID study was withdrawn this month by respected British medical journal The Lancet over data concerns.

Researchers in Britain said dexamethasone, used to fight inflammation in other diseases, reduced death rates of the most severely ill COVID-19 patients by around a third, and they would work to publish full details as soon as possible.

But hours later South Korea's top health official cautioned about the use of the drug for COVID-19 patients due to potential side effects.

"We have been burned before, not just during the coronavirus pandemic but even pre-COVID, with exciting results that when we have access to the data are not as convincing," said Dr. Kathryn Hibbert, director of the medical intensive care unit at Harvard's Massachusetts General Hospital.

Hibbert said published data would help her evaluate the findings and see which patients benefited the most and at what dose.

"I am very hopeful this is true because it would be a huge step forward in being able to help our patients," she said, but added she would not change practice at this point.

Steroids can suppress immune systems, warned Dr. Thomas McGinn, deputy physician-in-chief at New York's largest healthcare system, Northwell Health where, he told Reuters, physicians are using steroids on a case-by-case basis.

"We have to see what the study looks like given the current environment of retractions," said McGinn. "I just wait to see the real data, see if it's peer reviewed and gets published in a real journal, he said.

University of Washington professor of medicine Dr Mark Wurfel urged the researchers to put out data before official publication.

"That would be very, very helpful in terms of helping us align our patient populations with theirs and decide whether it's appropriate to apply this therapy to our patients."