The University of Rochester Medical Center (URMC) and Rochester Regional Health (RRH) have begun a new clinical trial that will evaluate the safety and efficacy of a third dose of the Pfizer/BioNTech COVID-19 vaccine. The vaccine is currently approved for a two dose regimen. This study represents an important step in the development of long-term vaccination strategies to protect against circulating and emerging variants of the virus.
“While widespread vaccination is the key to moving past the current health crisis, COVID-19 has the potential to become a seasonal and mutating virus,” said Ed Walsh, M.D., and infectious disease specialist at URMC. “This study will help us understand important questions about the safety and immunogenicity of multiple doses of an mRNA vaccine, information that could ultimately enable us to extend the protection of vaccines and develop tailor-made, variant-specific boosters.”
URMC and RRH have been involved in the development of the Pfizer/BioNTech COVID-19 vaccine since the launch of phase 1 clinical trials in May 2020 when volunteers in Rochester were among the first in the nation to receive the then experimental vaccine. Rochester was also a site for the phase 2/3 clinical trials that ultimately led to the vaccine’s emergency use authorization (EUA) by the U.S. Food and Drug Administration last December. Since then, tens of millions of people across the globe have received at least one dose of the Pfizer/BioNTech vaccine.
The new study will involve individuals who participated in the phase 1 trials last spring, all of whom were fully vaccinated more than 6 months ago. Over the next several weeks, researchers will dose 144 volunteers, including 35 in Rochester, with a booster dose of the EUA-approved Pfizer/BioNTech vaccine. Rochester is one of four sites in the U.S. involved in the study.
The local studies are led by Walsh and Ann Falsey, M.D.; both hold faculty appointments in the URMC Department of Medicine, Infectious Diseases and are members of the Infectious Disease Unit at RRH. Pfizer contracted with URMC to conduct the clinical trial in Rochester and the recruitment of study volunteers and testing of the vaccine will occur at Rochester General Hospital.
While the duration of protection provided by the Pfizer/BioNTech vaccine is unknown, it is expected that immunity wanes over time, a phenomenon common in vaccines for other infectious diseases. The trial will measure the boost to the immune system and evaluate in the lab whether antibodies and other immune cells generated after the third dose provide protection against coronavirus variants. The study will also seek to answer how well a third dose of the vaccine is tolerated in healthy volunteers, and researchers will closely monitor participants for side effects.
The findings of the study will also be important as vaccine developers have turned their focus to the development of vaccines that can be tailored to meet the threat of emerging strains of the virus. Pfizer and BioNTech announced today that the companies have begun discussions with regulatory agencies regarding studies to evaluate a modified version of their approved vaccine.
“While we have not seen any evidence that the circulating variants result in a loss of protection provided by our vaccine, we are taking multiple steps to act decisively and be ready in case a strain becomes resistant to the protection afforded by the vaccine. This booster study is critical to understanding the safety of a third dose and immunity against circulating strains,” said Albert Bourla, Chairman and Chief Executive Officer, Pfizer. “At the same time, we are making the right investments and engaging in the appropriate conversations with regulators to help position us to potentially develop and seek authorization for an updated mRNA vaccine or booster if needed.”