Nirsevimab for RSV Prevention in Nova Scotia Infants

CCfV is conducting a study that will collect samples and health information to look at infant RSV protection levels after receiving the current RSV prevention drug (nirsevimab).

Respiratory Syncytial Virus (RSV) is a germ that can cause infections of the breathing tubes. Most RSV infections just result in symptoms similar to a simple cold (such as a runny nose, sneezing and cough). However, RSV infection can be more serious in young babies, whose lungs and breathing tubes are still very small and whose body’s defense cannot fight germs very well and those born before their expected time or with certain lung or heart conditions.  RSV is the most common cause of infection of the breathing tubes and some lung infection in young infants. Severe RSV in young babies can cause wheezing and asthma later in childhood.

Infants less than 8 months of age are eligible for the Nova Scotia RSV prophylaxis (prevention) program when they are born during or entering their first winter season.

In past years there was a drug called palivizumab that was given monthly to children at increased risk to get sick from RSV during the winter season (October to March).  In April 2023, Health Canada approved a new drug called Beyfortus^TM (nirsevimab) to prevent RSV.  This drug was shown to provide protection with just one injection.  This replaced palivizumab as part of the Nova Scotia RSV Prevention Program in the winter of 2024, but it was only available to high-risk infants such as those who were born very premature or with heart or lung issues. Nirsevimab is now recommended to all infants during the winter season.

You may be able to take part it your child is eligible for the Nova Scotia Respiratory Syncytial Virus (RSV) prophylaxis (preventative treatment against infection) program.

You may be eligible if:

• you are expecting to deliver your baby during RSV season (October 12, 2026 – May 8, 2027), OR
• your baby was born after May 1, 2026, and is less than 8 months old

The study involves two visits to collect blood samples, optional nasal swabs and information about your child’s health.

• Visit 1 will take place before your child receives nirsevimab and visit 2 will happen about one year later.
• You would receive the nirsevimab injection as you normally would as part of your usual care.
• The study visits will be at the Canadian Center for Vaccinology (CCfV) at IWK Health.

Newborns will be given the injection before they are discharged from hospital, and older infants can receive it from their health care provider starting October 25, 2026.