Drew Weissman

Drew Weissman (born September 7, 1959, Lexington, Massachusetts, U.S.) is an American immunologist whose groundbreaking research into RNA (ribonucleic acid) opened the path to the development of RNA therapeutics, most notably the generation of messenger RNA (mRNA) vaccines. In the late 1990s and early 2000s Weissman and his colleague the Hungarian-born immunologist Katalin Karikó discovered that mRNA can induce immune responses against specific disease-causing agents. They further found that by introducing changes in mRNA nucleosides (the structural subunits of RNA), it was possible to modify these immune responses. The team’s discoveries enabled the development in 2021 of the first mRNA vaccines, which were targeted against SARS-CoV-2, the coronavirus that caused the COVID-19 pandemic. For their breakthrough work, Weissman and Karikó were awarded the 2023 Nobel Prize in Physiology or Medicine.

Early life and education

Weissman was raised in Lexington, Massachusetts, where he enjoyed sports in his youth, particularly martial arts. He was also interested in science from a young age. His father was an engineer, and, while in high school, Weissman worked for his father’s company, which specialized in making optical mirrors for use in satellites.

He later studied biochemistry and enzymology at Brandeis University, from which he graduated with a bachelor’s degree and a master’s degree in 1981. He then attended Boston University, where he earned an M.D. degree and a Ph.D. in immunology and microbiology in 1987. In 1990, after completing a residency in internal medicine at Beth Israel Deaconess Medical Center in Boston, Weissman accepted a fellowship to work at the National Institutes of Health in Maryland. There he carried out research under the guidance of American immunologist Anthony Fauci.

mRNA vaccines

In 1997 Weissman joined the faculty of the Perelman School of Medicine at the University of Pennsylvania (Penn) in Philadelphia. He began carrying out studies in dendritic cells, which serve a key role in immune surveillance, and increasingly focused his efforts on the development of mRNA therapeutics, particularly in the areas of vaccine development and gene therapy. Not long after starting at Penn, Weissman met Karikó, who shared an interest in finding ways to leverage mRNA to stimulate the body to develop immunity against viral pathogens. Karikó began generating mRNA for Weissman’s research, and the two soon began collaborating on mRNA vaccine studies.

Weissman and Karikó quickly discovered in their initial studies that mRNA is highly immunogenic, provoking counterproductive immune responses. However, Karikó had observed that another type of RNA, transfer RNA (tRNA), did not have the same immunogenic effects, which led Weissman and Karikó to experiment with modified nucleosides. In 2005 they reported a major breakthrough: by introducing modified nucleosides, such as pseudouridine, into mRNA, it was possible to generate an mRNA molecule with the ability to evade immediate immune detection. Consequently, the modified mRNA remained active longer than unmodified mRNA, allowing it to enter cells and trigger the production of proteins with the ability to resist disease. The technology became known as non-immunogenic, nucleoside-modified RNA, which Weissman and Karikó patented in 2005.

The promise of non-immunogenic, nucleoside-modified RNA inspired Weissman and Karikó to start a company called RNARx. They successfully licensed the technology to the biotechnology companies Moderna and BioNTech. In 2021, under pressure during the COVID-19 pandemic to develop a vaccine that could help prevent or reduce the severity of infection with SARS-CoV-2, Moderna and a joint effort by the biopharmaceutical company Pfizer and BioNTech independently accelerated research into using mRNA to generate COVID-19 vaccines. Shortly after obtaining the genetic code of SARS-CoV-2, scientists at Moderna and Pfizer-BioNTech separately prepared experimental mRNA vaccines.

Other mRNA therapeutics

Weissman also carried out extensive research into other mRNA therapeutics. For example, he was involved in critical studies in collaboration with other researchers on the use of lipid nanoparticles (LNPs) as a mechanism for mRNA delivery to specific cells. In studies in mice and monkeys, he and his colleagues were among the first to show that a modified mRNA-LNP vaccine could induce immune defense against infection with Zika virus. His research team further applied mRNA-LNP technology to gene therapy for the treatment of diseases such as cystic fibrosis and certain forms of liver disease and investigated the development of mRNA vaccines for a variety of other diseases, including vaccines against herpes simplex, hepatitis C, and norovirus. Weissman was also involved in the development of a pan-coronavirus vaccine with the potential to protect against every variant of coronavirus that could emerge in the future.

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Awards and honors

In addition to the Nobel Prize, Weissman received numerous other honors and awards during his career. Notably, together with Karikó, he was a recipient of the Rosenstiel Award (2020), the Louisa Gross Horwitz Prize (2021), and the Lasker-DeBakey Clinical Medical Research Award (2021). In 2022 he became an elected member of the American Academy of Arts and Sciences.