The U.S. government is exercising its option for an additional 650,000 doses of Eli Lilly’s neutralizing antibody bamlanivimab (LY-CoV555) for $812.5 million, following the drug’s Emergency Use Authorization in November for mild-to-moderately ill COVID-19 patients at high risk.

Doses are to be delivered through the end of January, with “at least” 350,000 of the extra doses delivered this month. The initial deal, struck for $375 million, called for 300,000 vials of bamlanivimab delivered through the end of 2020.

Under the Operation Warp Speed allocation program, bamlanivimab will be given to patients free of charge via weekly distribution to states and territories based on the number of confirmed COVID-19 cases from the previous seven days.