Prevention of RSV Infection in Infants by Administering Nirsevimab to Infants, With or Without Maternal RSV Vaccination

Inclusion Criteria: 1. Pregnant women 2. Provide informed consent prior to study enrolment 3. Willing and able (in the site investigator's opinion) to comply with all study requirements 4. More than 18 years of age 5. Between 32 and 36 weeks of gestation 6. Able to read and complete the eHealth questionnaire in French or English 7. Willing to receive maternal vaccine in pregnancy, if allocated 8. Willing for the baby to receive infant nirsevimab 9. Willing for their data to be re-used as part of the joint analysis with PIPELINE-RSV-International trial 10. Affiliated to social security regime or an equivalent system Inclusion Criteria - Infants: 1. Live-birth to mother enrolled in the study 2. Informed consent from the mother, and the other legal representative (partner / co-parent) when applicable Exclusion Criteria: 1. Major illness of the maternal participant or conditions of the foetus that, in the investigator's judgment, would substantially increase the risk associated with the maternal or infant participant's participation in and completion of the study 2. Any suspected or confirmed condition in the foetus that in the opinion of the site investigator would contraindicate participation of the future newborn/infant in the study 3. High risk of prematurity as judged by treating clinician 4. Multiple pregnancy (i.e. twins, triplets or more) 5. Previous participation in the PIPELINE-RSV trial 6. Receipt of any previous RSV prevention product in this pregnancy or currently participating in another interventional RSV prevention trial 7. Any contraindication for receipt of intramuscular injection (bleeding diathesis or a condition associated with prolonged bleeding) or of vaccine (history of severe allergic reaction (e.g. anaphylaxis) to any component of the vaccine) 8. History of Guillain Barré Syndrome (GBS)