On May 3, 2023, the U.S. Food & Drug Administration (FDA) announced the approval of the first vaccine for the prevention of respiratory syncytial virus (RSV) infection, Arexvy™. This vaccine is approved for people 60 and older, especially those with underlying health conditions. RSV is a highly contagious respiratory virus that commonly causes mild, cold-like symptoms. However, it can impact infants or older adults very seriously, causing life-threatening pneumonia and bronchiolitis. Each year, RSV leads to 6,000 to 10,000 deaths in adults over age 65. Health conditions like a weakened immune system and heart or lung disease put individuals at a much greater risk of contracting RSV and experiencing a severe infection, so it is recommended that they receive the vaccine when it becomes available.
The safety and efficacy of Arexvy™ is based on a randomized, placebo-controlled clinical study of people 60 and older. The study is ongoing, and participants will be monitored through three RSV seasons to help determine the duration of effectiveness and the safety of repeated vaccinations with Arexvy™. In this study, 12,500 participants received Arexvy™ and 12,500 participants received a placebo. A single dose of the vaccine from the first RSV season significantly reduced the risk of RSV-associated lower respiratory tract disease by 82.6% and severe RSV-associated lower respiratory tract disease by 94.1%. Atrial fibrillation was reported 30 days into the study in 10 participants receiving Arexvy™ and 4 participants receiving placebo.
Two additional studies of Arexvy™ were conducted, reviewing 2,500 participants who received the vaccine along with an FDA-approved influenza vaccine. Two participants developed a rare form of inflammation affecting the brain and spinal cord, acute disseminated encephalomyelitis (ADEM), and one of these participants died. Additionally, one participant developed Guillain-Barre syndrome 9 days after receiving Arexvy™. The FDA is requiring a post marketing study to assess risks for ADEM and Guillain-Barre syndrome, and GlaxoSmithKline will also review atrial fibrillation risk. Arexvy™ was granted Priority Review designation.