Drew Weissman (born September 7, 1959) is an American physician and immunologist known for his contributions to RNA biology.

[2] With biochemist Katalin Karikó, Weissman received the Nobel Prize in Physiology or Medicine in 2023 "for their discoveries concerning nucleoside base modifications that enabled the development of effective mRNA vaccines against COVID-19".

[17] In 1997, Weissman moved to the University of Pennsylvania to start his laboratory in order to study RNA and innate immune system biology.

[18] At the university, Weissman, an immunologist studying vaccines, met his future colleague and collaborator Katalin Karikó at a photocopier,[19] where they sympathized about the lack of funding for RNA research.

[20] Immunologist Weissman began collaborating with biochemist Karikó, who switched her focus to the application of RNA technology to vaccines.

"[22] One of the major scientific obstacles they faced was that the RNA caused unwanted immune and inflammatory reactions as adverse side effects.

Beginning in 2005, they published several landmark studies that used synthetic nucleosides to modify the RNA to prevent its degradation by the body.

In 2020 their modified RNA technology became the key foundational component of the Pfizer/BioNTech and Moderna COVID-19 vaccines, which were deployed worldwide against the COVID-19 pandemic.

[46] Weissman is the co-inventor on several patents, including US8278036B2[47] and US8748089B2,[48] both with his colleague Katalin Karikó, which detail the modifications required to make RNA suitable for vaccines and other therapies.