Preventive treatment against respiratory syncytial virus (RSV) for babies

Respiratory syncytial virus (RSV) is a very common virus, especially during fall and winter. Up to 3 in 10 babies develop a severe lung infection (bronchiolitis or pneumonia) when they catch this virus for for the first time. For some babies, the infection can lead to complications and require hospitalization.

Immunization is the best protection against RSV.

Immunization, using preventive treatment:

• protects babies from serious forms of RSV;
• reduces hospital admissions related to RSV.

Preventive treatment provides the baby with antibodies that help fight RSV and prevent complications from the infection.

The treatment is given by injection and protects the baby for at least 5 months.

Protection is offered free of charge during the RSV immunization campaign (generally in fall and winter) for:

• newborns born during the RSV season (generally in fall and winter);
• babies born on or after April 1, 2026 who have not already received it;
• babies born on or after February 1, 2026 who have not received it and who are more at risk of complications, namely:
  • babies who were born at less than 37 weeks of pregnancy;
  • babies who have at least one of the conditions that increase the risk of complications;
• babies who were born on or after March 1, 2025 who have at least one of the conditions that increase the risk of complications. They could also receive a 2nd dose in their 2nd RSV season.

If in doubt, a health professional can help you determine if your child is concerned.

Certain conditions increase the risk of complications from RSV, such as:

• being born at less than 32 weeks of pregnancy;
• cystic fibrosis;
• trisomy 21 (Down syndrome);
• lung diseases: bronchopulmonary dysplasia, chronic lung disease or moderate or severe pulmonary arterial hypertension;
• respiratory problems caused by a muscular disorder or malformation: significant impaired clearance of secretions from the airways due to a neuromuscular disorder or a congenital anomaly of the upper airways;
• disease or malformation of the heart: congenital heart disease or hemodynamically significant cardiomyopathy;
• bone marrow, stem cell or solid organ transplant.

Preventive treatment against RSV is safe. Most of the time, it does not cause any reaction.

Other health problems, such as a cold or gastroenteritis, may arise by chance after administration, but are not caused by preventive treatment.

Wait 15 minutes before leaving the premises. If an allergic reaction occurs, the symptoms will appear within a few minutes of administration of preventive treatment.

If symptoms appear, inform the health professional immediately, who will be able to treat the reaction on site.

If there is redness, pain or swelling at the injection site, apply a cold wet compress to the injection site.

Use medication for fever or discomfort as needed (such as acetaminophen, e.g., Tylenol^® or Tempra^®).

Consult a health professional in any of the following situations:

• if there are serious or unusual symptoms;
• if symptoms get worse instead of better;
• if the symptoms last more than 48 hours.