FDA approves Abrysvo vaccine for the prevention of respiratory syncytial virus (RSV) in infants though active immunization of pregnant individuals 32-36 weeks of gestational age

Abrysvo is unadjuvanted and composed of two preF proteins selected to optimize protection against RSV A and B strains and was observed to be safe and effective.

Abrysvo's approval as the first and only maternal immunization to help protect newborns immediately at birth through six months from RSV marks a significant milestone for the scientific community and for public health,” said Annaliesa Anderson, Ph.D., Senior Vice President and Chief Scientific Officer, Vaccine Research and Development, Pfizer. “We are incredibly grateful to the clinical trial participants and study investigator teams around the world, as well as our Pfizer colleagues, for their commitment to making this vaccine available. Today, a long-sought-after goal to deliver a maternal vaccine that will help protect infants six months of age or younger – when they are at greatest risk of possible serious consequences from RSV – has been achieved.”

The FDA’s decision is based on the data from the pivotal Phase III clinical trial (NCT04424316) MATISSE (MATernal Immunization Study for Safety and Efficacy), a randomized, double-blinded, placebo-controlled Phase III study designed to evaluate the efficacy, safety, and immunogenicity of the vaccine against LRTD and severe LRTD due to RSV in infants born to healthy individuals vaccinated during pregnancy. These results were published in The New England Journal of Medicine in April 2023 (previously cited).

"Newborns and young infants – whose immune systems are still developing and are not yet strong enough to defend against infections – may now be protected from RSV from the moment of birth through maternal immunization,” said Eric A.F. Simões, M.D., Clinical Professor, Pediatrics-Infectious Diseases, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora. “The approval of Pfizer’s Arbysvo is a major triumph as it helps ensure no delay in potential RSV protection during an infant’s most vulnerable first six months of life and offers healthcare providers a new opportunity to help prevent severe RSV.”

RSV is a contagious virus and a common cause of respiratory illness worldwide. The virus can affect the lungs and breathing passages of an infected individual, potentially causing severe illness or death. The disease burden of RSV in young children is staggering with virtually all children getting an RSV infection by the time they are two years old. In the United States, approximately 500,000 to 600,000 infants experience LRTD due to RSV each year and it is a leading cause of hospitalization in children less than one year of age.