Drew Weissman

Drew Weissman is a physician-scientist in immunology at University of Pennsylvania in the Department of Medicine. Weissman is known for winning a Nobel Prize in Medicine jointly with Katalin Karikó and their research on the immune system recognition of mRNA, which led the way for the development of mRNA COVID-19 vaccines.

Weissman grew up in Lexington, Massachusetts. His father was an engineer, and his mother was a dental hygienist. Weissman’s wife, Mary Ellen Weissman, is a child psychologist, and they have two daughters.

Weissman completed a bachelor’s degree and master’s degree from Brandeis University and then completed an MD and PhD (1987) at Boston University. Weissman was a fellow at the National Institutes of Health, where he studied HIV in the laboratory headed by Dr. Anthony Fauci. Weissman joined the University of Pennsylvania as faculty in the Division of Infectious Disease in 1997, becoming full professor in 2012.

Weissman began collaborating with University of Pennsylvania colleague Katalin Karikó in 1998. Karikó’s research was focused on mRNA as a therapeutic for diseases, and Weissman was interested in targeting a type of immune cell, dendritic cells, for vaccine development. In 2023, Weissman and Karikó jointly won the Nobel Prize in Medicine “for their discoveries concerning nucleoside base modifications that enabled the development of effective mRNA vaccines against COVID-19.”

Together, they advanced the field of RNA research, showing that naturally occurring modified nucleosides in RNA are the mechanism the cell and the innate immune system uses to distinguish between foreign RNA and self RNA. Up until this point, clinical applications for mRNA were hindered by immune responses, and this discovery meant that mRNA could be modified in such a way as to avoid harmful immune responses, making the introduction of mRNA into a person safer and more effective. Weissman and Karikó demonstrated that by replacing uridine in mRNA with naturally occurring modified bases such as pseudouridine, the inflammatory response was decreased. Researchers later used this knowledge to deliver mRNA into human cells to produce SARS-CoV-2 viral proteins as vaccines against COVID-19. Weissman consulted with BioNTech, and his lab received funding from the company. The work of Weissman and Karikó laid critical groundwork for both the Moderna and Pfizer-BioNTech COVID-19 mRNA vaccines.