This weekend, Stephen Hahn, the commissioner of the U.S. Food and Drug Administration, attracted criticism when he substantially overstated the benefits of an experimental Covid-19 therapy. At a press conference with Trump, Hahn said that a treatment using blood plasma from recovered patients could save 35 of every 100 people who would have died. Those high-profile remarks were incorrect, and they were repeated by others in the Trump administration. Hahn late Monday clarified some of what the data on blood plasma actually show.

But the episode has raised questions about how the agency will review a vaccine, as well as its scientific independence. Senior Editor for Health Care Drew Armstrong spoke to Hahn about the agency’s role in an increasingly politicized federal virus response.