Monoclonal antibodies were once the star of COVID-19 outpatient treatments. Since they first became available in 2020 – even before the first vaccines – more than 3.5 million infusions of the factory-grown proteins have been given to patients in the U.S. to help reduce risk of hospitalization.
But one by one, different monoclonal treatments have lost their efficacy against new variants of the coronavirus. The rise of Paxlovid antiviral pills earlier this year, further dented their appeal.
