Respiratory syncytial virus (or RSV) is a common virus that causes respiratory illness. In infants, especially those less than six months old, RSV infection can cause inflammation of the airways, which may require hospitalization. Some children develop wheezing or asthma that may continue for years after the RSV infection is over. One in 10 Native American babies will be hospitalized with RSV in the first year of life. There is currently no licensed vaccine to prevent RSV in infants or adults.
One way to protect infants from some diseases is to vaccinate pregnant women. The pregnant woman then passes her protection against the disease to her infant through the placenta, which protects infants for the first few months of their life. This is called maternal immunization. In the US, all pregnant women are recommended to receive vaccines for influenza (the flu) and pertussis (whooping cough) to protect their infants from those diseases.
A new RSV vaccine for pregnant women was developed called the RSV F Vaccine. In 2017-2019, the Center participated in a large randomized, double-blind, placebo-controlled trial that was conducted in more than 80 sites in 11 different countries to evaluate whether this investigational RSV vaccine given to pregnant women prevented RSV disease in their babies. The first results were announced in March 2019 and the vaccine was found to be safe and well-tolerated for both pregnant women and their infants. While the vaccine was not found to prevent medically significant RSV disease, it was somewhat effective at preventing hospitalizations due to RSV infection among infants in the first 3 months of life. Additional analyses are ongoing.