NEW YORK (NYTIMES) - In April 2020, US federal scientists reported the first glimmer of hope against the new coronavirus: A large clinical trial had found that an antiviral drug, remdesivir, shortened recovery time in hospitalised patients from 15 to 11 days.

The drug was authorised a few months later and has also been cleared in more than 50 other countries. But remdesivir's use has been limited to hospitalised patients, and its intravenous administration has been an obstacle.

Two new studies, published in late December, indicate that both issues could be improved in the not-too-distant future. One found that infused remdesivir appears to be markedly effective when given earlier in the course of illness, before a patient is hospitalised. And a study in monkeys suggests that inhaled remdesivir could eventually replace infusions.

The study of remdesivir treatment in patients who were not hospitalised, published in the New England Journal of Medicine, involved 592 patients at risk for severe disease who had not been hospitalised. Half received a three-day course of remdesivir and the others got a placebo.

Remdesivir greatly reduced patients' chances of hospitalisation or death: five of 279 patients, or 1.7 per cent, who received remdesivir were hospitalised by Day 28 of their infection, compared with 18 of 283, or 6.5 per cent, who got a placebo.

What's more, because all variants of the virus carry the particular enzyme that remdesivir blocks, the drug should work against Omicron or any other new variant that happens to emerge.

A separate study, supported by Gilead Sciences, the maker of remdesivir, tested an inhaled version of the drug on African green monkeys.

As reported in the journal Science Translational Medicine, the researchers used a 20-fold-lower dose of the inhaled drug than what is used in an intravenous infusion. Yet that low dose resulted in a 53 per cent higher concentration of the drug in the animals' lungs.

The researchers also reported that inhaled remdesivir was as effective as the intravenous version in reducing the amount of virus in the animals' lungs.

Much more research is needed before the inhaled version of the drug can be used in people. But if remdesivir could eventually be inhaled at home, the hope is that it could provide a more convenient way for patients at high risk to be protected from severe disease.