A new pill designed to treat active COVID-19 infections was just approved by the UK, the first country to do so

• The UK on Thursday became the first country to approve Merck's new COVID-19 antiviral, molnupiravir.
• The pill is the first drug on the market designed specifically to target active COVID-19 infections.

The UK on Thursday became the first country to approve a new antiviral pill designed specifically to treat COVID-19 infections.

The pill, developed by Merck and Ridgeback Biotherapeutics, was found to halve the likelihood of death or hospitalization from COVID-19 during clinical trials.

In a statement early Thursday, Merck said the UK government had ordered 480,000 courses of the drug, molnupiravir, while the US government had ordered 1.7 million courses. Merck is seeking emergency authorization for molnupiravir from the US Food and Drug Administration.

Experts say the drug could prove to be a "game changer" if it can stop people with COVID-19 from becoming very sick. It also has the advantage of being an oral drug, which means you don't need to be in a hospital or clinic to take it.

The UK's approval of the drug is based on results from a recent trial, which tested the pills on 775 adults with mild to moderate COVID-19. Of this group, 7% who received the pill ultimately were hospitalized or died, compared with 14% of those who got a placebo, Merck and Ridgeback said last month.

Analysts are estimating that Merck will make about $22 billion in revenue from selling molnupiravir across the world over the next 10 years. The US has agreed to pay $712 per treatment course, but the cost varies by country.