US health regulators approved a pill Wednesday to treat coronavirus symptoms at home for those who get sick, and likely keep them out of a hospital.

The drug, Paxlovid, from Pfizer, is getting rave reviews for its ability to treat the most serious aspects of COVID-19, with roughly 90% effectiveness, while also having limited side effects. All other treatments require an injection or an IV.

The Food and Drug Administration (FDA) approved Paxlovid for anyone 12 and older, based on a Pfizer survey of more than 2,000 test patients. The results showed the drug cuts the risk of hospitalization and death by 89%, when given to patients with mild-to-moderate symptoms.

But there are challenges. The drug is only available by prescription after a patient gets a positive test for the virus and it is most effective when given within five days of symptoms.

Patients who catch the virus might not realize soon enough they have symptoms. And those who already distrust vaccines might balk at taking a pill from one of the vaccine manufacturers.

And for the moment, the drug will be hard to find. The US will ration shipments to those areas of the country hardest hit by COVID-19.

Pfizer says it takes about nine months to manufacture the drug but it expects to cut the manufacturing time in half sometime in the next year. It said it plans to ship 80 million doses of the drug to other nations as well.

The FDA is also expected to approve another at-home COVID-19 drug from Merck, and the Merck and Pfizer pills are expected to offer protection against the omicron variant, now the dominant strain of COVID-19.

Although there has only been one reported death from that strain in the US, hospitals are overwhelmed in some states, particularly the Midwest, with the US is averaging 140,000 new infections per day./agencies