News Release
kariko and weissman

PHILADELPHIA – The U.S. Food and Drug Administration (FDA) has given the first full approval to a COVID-19 mRNA vaccine, which uses modified mRNA technology invented and developed by scientists in the Perelman School of Medicine at the University of Pennsylvania, whose years of research in mRNA science laid a critical piece of the foundation for the largest global vaccination campaign in history. 

A research partnership between Drew Weissman, MD, PhD, the Roberts Family Professor in Vaccine Research, and Katalin Karikó, PhD, an adjunct professor of Neurosurgery at Penn and a senior vice president at BioNTech, dating back two decades led to the development of modified mRNA technology that has been licensed as a key foundational component of the highly effective Pfizer/BioNTech mRNA COVID-19 vaccine being deployed worldwide. The Pfizer/BioNTech vaccine was the first to receive FDA Emergency Use Authorization (EUA) in December 2020 for those 16 years of age or older, the age group for which the full vaccine approval applies. In May 2021, the EUA was expanded to include adolescents ages 12 to 15 and, in August, it was amended again to allow for a third dose for certain people who are immunocompromised. The vaccine remains available under EUA for these groups. Moderna Therapeutics, which was granted EUA for its mRNA COVID-19 vaccine in December, also uses the same modified mRNA technology created at Penn. 

“We are tremendously proud to celebrate this milestone today, and to recognize its roots at Penn, where Drs. Weissman and Kariko’s commitment and vision led to discoveries which have contributed to one of the world’s most impactful scientific achievements,” said J. Larry Jameson, MD, PhD, executive vice president of the University of Pennsylvania for the Health System and dean of the Perelman School of Medicine. “Today’s FDA approval should provide even more confidence in the safety and efficacy of COVID-19 vaccines as the fight against this deadly virus continues and encourage everyone who is eligible and has not yet received a vaccine to take this lifesaving step to protect themselves and those around them.”

pfizer vaccine

For over a decade, Weissman and Kariko worked to chemically modify mRNA so it could be used safely and effectively in vaccines. Many vaccines stimulate immunity and prepare the body to fight against a specific virus by using a weakened or dead version of the actual virus. mRNA vaccines, however, carry a genetic code that causes the body’s cells to produce proteins that the immune system recognizes as the virus. The immune system then builds up the necessary defenses against the viral proteins to protect against future infection and severe disease. 

Prior to Weissman and Kariko’s breakthrough research, published in 2005, mRNA vaccines being developed to prevent infectious diseases did not effectively and safely elicit protective immune-system responses in animal models. Weissman and Kariko changed the way the mRNA was made by including specific naturally occurring mRNA modifications that make the mRNA safer, more stable, and effective for prophylactic and therapeutic purposes.

Weissman and Kariko received their first COVID-19 vaccinations together at Penn Medicine in December 2020, in a moment they called humbling and the fulfillment of a lifelong dream to contribute to a discovery to help humanity.

The FDA’s first COVID-19 vaccine approval comes at a critical point in the pandemic, as more contagious and deadly variants continue to spread. According to the World Health Organization, more than 211 million people have been diagnosed with COVID-19 worldwide, and the virus has taken the lives of more than 4.4 million people.  

Weissman and his colleagues are studying mRNA for other infectious-disease vaccines, including one for influenza and a single vaccine that may prevent various types of coronaviruses like COVID-19, SARS, and MERS—because even after the COVID-19 pandemic, other coronaviruses will still pose serious threats to public health.

To fight the COVID-19 pandemic that continues to surge in various parts of the globe, Weissman and his team are working with Chulalongkorn University in Thailand to help them generate an mRNA vaccine that will be specially dedicated to preventing COVID-19 in middle- and low-income countries. Outside of infectious diseases, Weissman believes that mRNA technology could be the future of protein replacement therapies, immunotherapeutics, cancer treatments, personalized cancer vaccines, genetic diseases, and other drug development.  

Editor’s Note: The Pfizer/BioNTech and Moderna COVID-19 mRNA vaccines both use licensed University of Pennsylvania technology. As a result of these licensing relationships, Penn, Dr. Weissman and Dr. Kariko have received and may continue to receive significant financial benefits based on the sale of these products. BioNTech provides funding for Dr. Weissman’s research into the development of infectious disease vaccines.


Penn Medicine is one of the world’s leading academic medical centers, dedicated to the related missions of medical education, biomedical research, excellence in patient care, and community service. The organization consists of the University of Pennsylvania Health System and Penn’s Raymond and Ruth Perelman School of Medicine, founded in 1765 as the nation’s first medical school.

The Perelman School of Medicine is consistently among the nation's top recipients of funding from the National Institutes of Health, with $550 million awarded in the 2022 fiscal year. Home to a proud history of “firsts” in medicine, Penn Medicine teams have pioneered discoveries and innovations that have shaped modern medicine, including recent breakthroughs such as CAR T cell therapy for cancer and the mRNA technology used in COVID-19 vaccines.

The University of Pennsylvania Health System’s patient care facilities stretch from the Susquehanna River in Pennsylvania to the New Jersey shore. These include the Hospital of the University of Pennsylvania, Penn Presbyterian Medical Center, Chester County Hospital, Lancaster General Health, Penn Medicine Princeton Health, and Pennsylvania Hospital—the nation’s first hospital, founded in 1751. Additional facilities and enterprises include Good Shepherd Penn Partners, Penn Medicine at Home, Lancaster Behavioral Health Hospital, and Princeton House Behavioral Health, among others.

Penn Medicine is an $11.1 billion enterprise powered by more than 49,000 talented faculty and staff.

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