WASHINGTON (CBS News) — The Food and Drug Administration announced Wednesday it has greenlighted Pfizer’s antiviral pills to treat COVID-19 for emergency use, allowing limited use of the drug in Americans as young as 12 who are at “high risk for progression to severe COVID-19.”

The new treatment option comes as doctors are facing a nationwide shortage of monoclonal antibodies to treat high-risk cases of the disease, with most formulas ineffective against the fast-spreading Omicron variant.

Early data suggests Pfizer’s pills, called Paxlovid, are effective against Omicron cases. The drugmaker says it works to block the ability of the virus to make copies of itself.