RSV Vaccine For Younger Adults Found Protective

Pfizer Inc. recently announced positive top-line data from the ongoing pivotal Phase 3 clinical trial evaluating a single dose of ABRYSVO versus placebo in adults 18 to 59 years of age at risk of developing severe respiratory syncytial virus (RSV)-associated lower respiratory tract disease (LRTD).

Highlights from this study include participants' achieving at least a fourfold increase in serum neutralizing titers for RSV-A and RSV-B one month following receipt of ABRYSVO compared to pre-vaccination.

During the trial, ABRYSVO was well-tolerated, and safety findings were consistent with those from previous investigations of ABRYSVO in other populations.

Among these U.S. adults, 9.5% have a chronic condition that puts them at risk of severe RSV disease, and this percentage rises to 24.3% among persons 50 to 64 years of age.

However, no RSV vaccines have been approved for adults aged 18 to 59.

Annaliesa Anderson, Ph.D., Senior Vice President and Head, Vaccine Research and Development, Pfizer, stated in a press release on April 9, 2024, "We are excited to address a significant unmet need, pending regulatory authority approval, as ABRYSVO has the potential to become the first and only RSV vaccine for adults 18 years and older."

In May 2023, the FDA approved ABRYSVO for the prevention of LRTD caused by RSV in individuals 60 years of age or older. 

Pfizer is currently the only company that has an approved RSV vaccine for protecting older adults and infants through maternal immunization.

The respiratory syncytial virus causes RSV disease. There are two major subgroups of RSV: RSV-A and RSV-B. Both subgroups cause disease and can co-circulate or alternate predominance from season to season.