Respiratory syncytial virus (RSV)

Important

The RSV prevention program for infants, toddlers, and pregnant individuals has ended for the 2024 to 2025 season. Please subscribe to this page to be notified by email when new guidance is added for the 2025 to 2026 season this fall.

What is respiratory syncytial virus (RSV)?

Respiratory syncytial virus (RSV) is a major cause of lower respiratory illness that affects the lungs and airways. Although the virus usually causes mild illness with cold-like symptoms, it can lead to more serious illness for babies, toddlers, older adults and those with underlying health conditions like asthma, chronic heart or lung disease and a weakened immune system.

RSV causes a high number of infections for these vulnerable populations, often resulting in hospitalizations. Vaccination and immunization can reducing severe outcomes from RSV, which may help protect health-care and hospital capacity within our region.

RSV prevention program

The Ontario government has expanded its RSV program to protect more high-risk populations during the 2024/2025 respiratory season. Starting in mid-October, RSV immunization will be available to infants and toddlers who are:

Up to twelve months of age, and
High-risk infants and toddlers up to 24 months of age experiencing:

chronic lung disease of prematurity (CLD), including bronchopulmonary dysplasia or chronic lung disease
hemodynamically significant congenital heart disease (CHD)
severe immunodeficiency
Down Syndrome or Trisomy 21
cystic fibrosis with respiratory involvement and/or growth delay
neuromuscular disease
severe congenital airway anomalies impairing the clearing of respiratory secretions

If you are unsure whether your child is eligible, contact us to discuss eligibility criteria.

Where to get Beyfortus in the KFL&A region

New parents delivering in hospital

Beyfortus will be given at the hospital after birth, before your baby is discharged.

New parents not delivering in hospital and for infants under one year of age

Health-care providers.
For those without health-care providers, book a RSV Beyfortus appointment at KFL&A Public Health.

Infants born in 2024 or high-risk children under 24 months of age

Health-care providers.
For those without health-care providers, book a RSV Beyfortus appointment at KFL&A Public Health.

How to protect your baby or toddler from RSV?

There are two safe and effective ways to protect your baby or toddler from RSV:

A preventive antibody medication that is given to a child (Beyfortus TM also known as Nirsevimab)

A vaccine that is given to a pregnant person (Abrysvo TM also known as RSVpreF)

Only one of these options is needed to help protect your child from RSV. Using both is not necessary unless recommended by a health-care provider.

Canada’s National Advisory Committee on Immunization (NACI) recommends Beyfortus given to a baby as the preferred option to protect against RSV. This is based on how well Beyfortus works, how long it provides protection and how safe it is.

What is Beyfortus?

Beyfortus is not a vaccine. It is a preventative antibody (protein) that helps fight the RSV virus. Antibodies are made naturally by our immune system to fight viruses. Beyfortus is a one-time injection that will protect your baby or toddler from RSV for six months.

Beyfortus eligibility

Your baby or toddler is eligible to receive Beyfortus during the RSV season (late fall to early spring, typically November to April) in Ontario if they are:

Born in 2024 before the RSV season

Born during the 2024/20525 RSV season

Under 24 months and vulnerable to developing severe RSV illness during their second RSV season, including but not limited to:
- chronic lung disease of prematurity (CLD), including bronchopulmonary dysplasia/chronic lung disease
- hemodynamically significant congenital heart disease (CHD)
- severe immunodeficiency
- Down Syndrome/Trisomy 21
- cystic fibrosis with respiratory involvement and/or growth delay
- neuromuscular disease
- severe congenital airway anomalies impairing the clearing of respiratory secretions

Is Beyfortus safe?

Canada’s National Advisory Committee on Immunization (NACI) has found that Beyfortus is safe for babies and young children and effective at preventing RSV-related illnesses that leads to hospitalization.
Side effects of Beyfortus are usually mild and last only a few days. Common side effects include:
- redness, swelling and pain at the injection site
- rash
- fever
- For more safety information, see NACI’s statement on RSV prevention in infants.

Vaccination in pregnancy

Abrysvo is a vaccine that can be given to a pregnant person to prevent RSV infection in their baby.

Given between 32 and 36 weeks of pregnancy if the baby’s due date is near the start of or during the RSV season.

Abrysvo helps the pregnant person’s immune system create antibodies that can be passed to the baby during pregnancy, which will protect the baby after birth until they are six months of age.
Speak with your health-care provider or contact KFL&A Public Health for more information if you are considering this vaccine. Beyfortus is the recommended option.

High-risk older adult RSV Prevention Program

How Older Adults Qualify for a Free RSV Vaccine

In fall 2023, Ontario introduced its first publicly funded high-risk older adult RSV vaccine program. Ontario will continue this program with expanded eligibility in 2024 and 2025