Hope for the Future: Finally an RSV Vaccine

Hope for the Future: Finally an RSV Vaccine
Anne Marmol, Pharm.D., MPH
M Health Fairview

A new bivalent respiratory syncytial virus (RSV) prefusion F protein-based vaccine (RSVpreF) for pregnant women is being studied to help limit the number of RSV cases in pediatrics. The purpose of vaccinations during pregnancy is to take advantage of passive immunity. Passive immunity occurs during the last three months of pregnancy and is when the antibodies from the mother are passed to the baby through the placenta. Those affected with RSV tend to be contagious for three to eight days and those with weakened immune symptoms, such as newborns, are at greatest risk of serious complications from the virus. It is noted that in the United States, nearly 60,000 hospitalizations occur among children less than five years old, resulting in nearly 500 deaths per year. Currently, there is no treatment for RSV, only symptomatic support.

Per the phase III clinical trial, MATISSE (Maternal Immunization Study for Safety and Efficacy), Pfizer’s RSV vaccination, which was given to expectant mothers in their late second trimester to third trimester of pregnancy, was approximately 82% effective (CI: 40.6%, 96.3%) at protecting babies against severe medically attended lower respiratory tract illness due to RSV for their first three months of life. At six months of life, the efficacy dropped to 69% (CI: 44.3%, 84.1%). No adverse events or safety concerns to either the mother or baby have been observed. Several companies currently have an RSV vaccine in their pipeline, but Pfizer and GSK have made the most progress with goals of seeking US regulatory approval in the near future. If approved, the RSV vaccine will be the first maternal vaccine against RSV.


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