RSV is a virus that can cause respiratory illness in people of all ages. Babies younger than 6 months are at the highest risk for serious illnesses, such as difficulty breathing, pneumonia, or bronchiolitis, which may require a hospital stay. When the RSVpreF (Abrysvo®) vaccine is given during pregnancy, it helps protect the baby from RSV during the first 6 months of life. Right now, we do not know how long this protection lasts or if it is safe to give the vaccine in later pregnancies. If you decide to take part in this study, both you and your unborn baby will join. You will have a visit with the study doctor to make sure the study is a good fit. To join, you must have gotten the RSYpreF vaccine during a previous pregnancy. If you join, you will be randomly assigned, like flipping a coin, to get either RSVpreF vaccine or a placebo. The placebo looks the same and is given the same as the study vaccine but has no active medicine. You will have 5 study visits. At these visits, the study team will ask about your past and current health, check your vital signs like blood pressure, and do a physical exam. You will give a small blood sample. You will also get the study vaccine or the placebo. The study team will do an obstetric exam and a prenatal ultrasound. For one week after you get the study vaccine or placebo, you will complete short surveys on a tablet or smart phone. You will be in the study for about 10 months. You can be paid up to $875 for your and your babies’ participation. Your baby will be in the study for about 6 months after birth, and you will have 4 more visits with your baby.

Who can Participate

You may be able to join this study if you are 18 or older and in your first or second trimester of pregnancy. You must have gotten the RSVpreF vaccine during a previous pregnancy.

Study ID

More information available at ClinicalTrials.gov: NCT06866405