Merck & Co Inc's experimental oral drug for Covid-19, molnupiravir, reduced by around 50 per cent the chance of hospitalisation or death for patients at risk of severe disease, according to interim clinical trial results.

Merck and partner Ridgeback Biotherapeutics plan to seek US emergency use authorisation for the pill as soon as possible and to submit applications to regulatory agencies worldwide. Due to the positive results, the phase 3 trial is being stopped early at the recommendation of outside monitors.

“This is going to change the dialogue around how to manage Covid-19,” Robert Davis, Merck's chief executive officer, told Reuters.

If authorised, molnupiravir, which is designed to introduce errors into the genetic code of the virus, would be the first oral antiviral medication for Covid-19.