The US Food and Drug Administration (FDA) on Thursday granted full approval for Pfizer’s oral antiviral treatment for Covid-19 for adults at high risk of progressing to severe disease.

Approval of the pill, which was initially approved in late 2021 for emergency use in the country, will give doctors more flexibility in prescribing them to adults with severe symptoms of Covid-19.

“Today’s approval demonstrates that Paxlovid has met the agency’s strict standards for safety and efficacy and remains an important treatment option for people at high risk of progression to severe COVID-19,” FDA’s Patricia Cavazoni said in a statement.

Data presented by the agency and the drug company during the advisory meeting helped ease safety concerns surrounding a potential return of Covid-19 symptoms after five days of Paxlovid use.

Concerns arose after several reports of a return of symptoms after treatment with the drug, including in important patients such as US President Joe Biden and infection doctor Anthony Fauci.