Nurse practitioners Taryn McCoy, left, and Gina LaFountain take inventory of supplies at a field hospital set up in one of the University of Mississippi Medical Center's parking garages, where HHS opened a monoclonal antibody clinic. (Rogelio V. Solis/AP)
correction

An earlier version of this article said the monoclonal antibodies treatment from Eli Lilly is no longer authorized. Distribution of the treatment has been paused because it is ineffective against some variants of the coronavirus. This version has been updated.

When Mike Burton came down with a breakthrough case of covid-19 earlier this month, the infection posed a double threat to his family. At 73, the retired surgeon faced elevated risk of serious illness. His wife, Linda, has a suppressed immune system, the result of drugs she takes after two liver transplants that put her in greater danger of life-threatening illness.