This study aims to check how safe and well-tolerated a second dose of RSVpreF is when given during later pregnancies, and to see how long the immunity lasts from a single dose given during a previous pregnancy by examining the blood of nonpregnant participants who had the vaccine before.
Had the RSVpreF or Abrysvo vaccine during a previous pregnancy.
Had an ultrasound scan at 18 weeks or later during their current pregnancy, with no major fetal problems detected.
Based on their medical history, physical check-up, and the doctor's judgment, they are found suitable to join the study.
Agrees to let their baby take part in the study and gives their permission.
Received any approved or experimental RSV vaccine since their previous pregnancy.
Has a pre-pregnancy body mass index (BMI) over 40 kg/m2.
History of a severe bad reaction to a vaccine or a serious allergic reaction (like anaphylaxis) to any ingredient in the study vaccine or a similar vaccine.
Current pregnancy problems or issues at the time of giving consent.