John Maassab spent most of his career at the University of Michigan working to develop a safe and effective live flu vaccine.

FluMist was his crowning achievement, the realization of “my life’s dream,” he called it after the vaccine was approved by the U.S. Food and Drug Administration in 2002.

Administered as a nasal spray, FluMist was based on weakened live virus strains that Maassab developed painstakingly over four decades.

FluMist earned billions of dollars for the pharmaceutical companies that produced it over its first two decades, according to the University of Michigan, and tens of millions for the university.

And then, in 2023, the British pharmaceutical company AstraZeneca stopped paying, according to a lawsuit filed by UM on Tuesday in U.S. District Court for the Eastern Di

See Full Page