The U.S. Food and Drug Administration (FDA) has officially approved the first oral antiviral Paxlovid for the treatment of COVID-19 in adults.

The treatment combines nirmatrelvir and ritonavir tablets for oral use among patients with mild-to-moderate COVID infection and at high risk for severe illness, hospitalization, or death.

The FDA stated on its website that Paxlovid will be strictly used for the treatment of COVID-19 in adults. It is not approved or authorized for use as a pre- or post-exposure prophylaxis to prevent infection.

"Paxlovid manufactured and packaged under the emergency use authorization (EUA) and distributed by the U.S. Department of Health and Human Services will continue to be available to ensure continued access for adults, as well as treatment of eligible children ages 12-18 who are not covered by today's approval," the agency added.

Paxlovid has been available in the U.S. for adults and teens for limited use only under the EUA. Thursday's announcement meant that the oral antiviral is fully approved, so more people could have access to it when battling the disease, according to CNN.

"While the pandemic has been challenging for all of us, we have made great progress mitigating the impact of COVID-19 on our lives. Today's approval demonstrates that Paxlovid has met the agency's rigorous standards for safety and effectiveness, and that it remains an important treatment option for people at high risk for progression to severe COVID-19, including those with prior immunity," FDA's Center for Drug Evaluation and Research director Patrizia Cavazzoni, M.D., said.

To get full approval and move past the EUA, a drug or treatment must pass the FDA's strict standards. The agency noted that Paxlovid proved its efficacy in its latest clinical trial after demonstrating substantial evidence of effectiveness in previous assessments.

"In considering approval of a drug, the FDA conducts a benefit-risk assessment based on rigorous scientific standards to ensure that the product's benefits outweigh its risks for the intended population," the FDA explained.

Paxlovid is the fourth drug and first pill to be approved for COVID-19 treatment. It will come with a black box warning because the drug combination has the potential to interact with many other types of medications, per CNN.