The US Food and Drug Administration on Tuesday authorized emergency use of a monoclonal antibody treatment for mild to moderate coronavirus disease 2019 illness in adults and most youth.

The federal agency announced in a statement that it authorized physicians to administer a combination of bamlanivimab and etesevimab to adults and children over the age of 12 and weighing at least 88 pounds who test positive for the virus and are high risk of developing severe symptoms.

Those older than 65 who suffer from chronic medical conditions are also included among those who can receive the treatment under the authorization, the FDA said.

Pharmaceutical company Eli Lilly, which manufactured the treatment, said in a separate statement that the two monoclonal antibodies should be administered together via a single intravenous infusion as soon as possible after a positive Covid-19 test is returned and within 10 days of symptoms onset.

Daniel Skovronsky, Eli Lilly’s chief scientific officer, said bamlanivimab had previously been authorized for emergency use to help prevent Covid-19 hospitalizations.

“With the risk of resistance emerging as various strains of the virus arise, bamlanivimab and etesevimab together could potentially allow efficacy against a broader ranger of naturally occurring SARS-CoV-2 variants as these new strains spread around the world,” he said, referring to the virus that causes Covid-19 by its technical name.

The FDA said clinical trial results of the two-antibody treatments showed a single intravenous infusion to patients with Covid-19 at high risk of disease progression “significantly reduced Covid-19 hospitalization and death” 29 days after the combination was administered.

“The data supporting this emergency authorization add to emerging evidence that points to the clinical utility of neutralizing antibodies for the treatment of Covid-19 in certain patients,” Patrizia Cavazzoni, acting direct of the FDA’s Center for Drug Evaluation and Research, said.

Monoclonal antibodies are proteins made in a laboratory to mimic the immune system’s ability to fight viruses, the FDA said, adding that bamlanivimab and etesevimab are monoclonal antibodies specifically directed against a protein present in the coronavirus and is designed to block its attachment to and infection of human cells.

Eli Lilly said more than 250,000 doses of the monoclonal antibody treatment are to be manufactured during the first quarter of the year with up to 1 million by mid-2021.