News that an experimental antiviral drug from Merck appears to halve the risk of hospitalization or death from Covid-19 has bolstered hopes of finding a simple at-home treatment for the virus.

The drug, molnupiravir, is given as a pill. It performed well enough in a late-stage clinical trial of adults at high risk of severe Covid-19 that the independent review board overseeing the study recommended that it be ended early. Now Merck and its partner Ridgeback Biotherapeutics will seek FDA authorization for the drug “as soon as possible,” they said Friday.

If those promising preliminary results hold, the new drug could help fill a significant gap in the world’s Covid-19 arsenal. As the pandemic nears the end of its second year, there are still only a handful of treatments for Covid-19 — and none that people can take at home. Finding a drug that can minimize the risk of severe illness could ease the burden on the country’s hospitals and blunt future surges of infection, in combination with vaccines and public health measures like mask-wearing.

Currently, “very few treatment options [are] available,” said Matthew Hall, a biologist at the National Institutes of Health’s National Center for Advancing Translational Sciences. “Someone can go to an infusion center and be infused with a neutralizing antibody, but [there’s] nothing in a pill form that's able to just be prescribed to take in early in an infection to reduce the severity of symptoms and the extent of symptoms.”

At a press conference Friday, the president’s chief medical adviser, Anthony Fauci, called the trial results “impressive” and “very good news.” Fauci said that Merck had briefed government health officials last night on the trial data.