Respiratory Syncytial Virus (RSV)

Respiratory syncytial virus, commonly referred to as RSV, is a highly contagious respiratory virus that circulates every year between fall and spring. By the age of 2, nearly all children have had RSV at least once.

Most people that get RSV will only have mild, cold-like symptoms. However, in infants and older adults, RSV can cause severe respiratory illness. It can lead to lung infections such as bronchiolitis (an infection of the small airways in the lungs) or pneumonia. It can also worsen chronic lung and heart diseases.

RSV is a leading cause of hospitalizations among children under the age of 1, and in rare cases, can be life-threatening. This is because young infants do not yet have fully developed lungs and immune systems. Older adults, whose immune systems are less efficient, are also at higher risk of severe illness and complications.

Fortunately, there is now a highly effective one-dose preventive antibody treatment (called Beyfortus®, or nirsevimab) that is available for infants in Ontario. Starting in October 2024, it will be available free of charge for eligible infants and high-risk children up to 24 months. In addition, vaccines are available for pregnant women, and for eligible adults aged 60 and older. Learn more at the links below.

Preventive antibody treatment for newborns and infants – Beyfortus
Maternal vaccine – Abrysvo
Vaccine for eligible adults aged 60 and older

Learn more about RSV:

How RSV spreads
Symptoms of RSV
If your child becomes ill
More information

Preventive antibody treatment for newborns and infants – Beyfortus

Until recently, RSV infections in infants couldn’t be prevented. However, a preventive antibody treatment that can help protect infants most at risk from an RSV infection is now available for free through Ontario’s publicly funded RSV prevention program. The preventive treatment (Beyfortus®, or nirsevimab) requires just a single dose, is highly effective, and provides protection for at least 6 months. It should be given just before or during active RSV season, which is typically from November to April.

Note: Beyfortus is a preventive treatment, and is not used to treat active RSV infection.

Starting in October 2024, Beyfortus will be available free of charge in Ontario to the following groups:

  • Infants born in 2024 before the RSV season
  • Infants born during the 2024/25 RSV season
  • High-risk children up to 24 months of age who have:
    • 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 clearing of respiratory secretions

Please speak to your child’s healthcare provider if you have questions about eligibility.

How does the antibody treatment work?

Beyfortus is a preventive treatment, and is not used to treat active infection. It is a “monoclonal antibody” treatment. Monoclonal antibodies are proteins that act like the protective antibodies your body makes to protect you from harmful viruses, bacteria and other germs.

The monoclonal antibodies in Beyfortus specifically recognize and target the RSV virus to help prevent severe illness in infants and young children if they are exposed to RSV. Protection is immediate and lasts for at least 6 months, when infants are most vulnerable to severe illness from RSV. Beyfortus is only needed once, as it gives an infant’s lungs and immune system enough time to mature and be more able to fight off RSV on their own during future RSV seasons.

Beyfortus is given by injection, and can be received at the same time as other seasonal or childhood vaccines.

Safety and efficacy

Clinical trials and real-world experience in other countries that have used Beyfortus, including the US, Spain and France, have shown that it is both safe and highly effective at protecting infants from severe RSV disease and RSV-related complications requiring hospitalization. Side effects are generally mild and last only a few days. They may include redness, swelling and pain at the injection site, rash, and/or fever.

Where to get Beyfortus for your infant

Starting in October 2024, Beyfortus will be offered to newborns at the hospital following birth. For infants born outside of a hospital setting, or who were born earlier in 2024, or for infants up to 24 months of age who have certain medical conditions, the treatment will be available through primary healthcare providers. Talk to your healthcare provider for more details.
 
Parents and caregivers of eligible infants in the EOHU region who do not have a healthcare provider, or who cannot access the Beyfortus treatment for other reasons, can contact the EOHU at 1-800-267-7120 to arrange an appointment for their child to receive the treatment.

A maternal vaccine (Abrysvo) is also available

As an alternative to the preventive antibody treatment for infants (Beyfortus), individuals residing in Ontario who are between 32 to 36 weeks pregnant and who will deliver near the start of or during the RSV season (November to April) can opt to receive an RSV vaccine. The vaccine (Abrysvo®, also known as RSVpreF) helps them produce antibodies that are passed on to their baby while they’re still in the womb, providing their newborn with protection for up to 6 months from birth. However, because it takes several weeks after receiving the vaccine for the mother’s immune system to produce the protective antibodies, if the baby is born earlier than expected, they may not be fully protected.

Canada’s National Advisory Committee on Immunization (NACI) recommends the preventive antibody treatment (Beyfortus) as the preferred option over the maternal vaccine. This recommendation is based on the effectiveness of Beyfortus, the immediacy and duration of protection it provides to the baby, and how safe it is.

Generally, only one of these products is needed to protect infants from RSV. Using both the preventive antibody treatment (Beyfortus) and the maternal vaccine (Abrysvo) is unnecessary except in certain circumstances (for example, a high-risk infant born to someone who received the vaccine).

Abrysvo may be available through primary care offices, obstetricians, hospitals, some public health units, and midwives. Please consult your healthcare provider if you are considering the Abrysvo vaccine.

Vaccine for eligible adults aged 60 and older

In the fall of 2023, Ontario launched its first publicly funded RSV vaccination program for high-risk older adults. This program will continue and expand in 2024/25, extending eligibility to adults aged 60 and older who are also:

  • Residents of long-term care homes, Elder Care Lodges, or retirement homes
  • Patients in hospitals receiving alternate levels of care (ALC), including similar settings like complex continuing care or hospital transitional programs
  • Patients undergoing hemodialysis or peritoneal dialysis
  • Recipients of solid organ or hematopoietic stem cell transplants
  • Individuals experiencing homelessness
  • Individuals identifying as First Nations, Inuit, or Métis

Eligible older adults may receive the RSV vaccine for free through healthcare providers, congregate living residences (such as long-term care homes and retirement homes), hospitals, or public health units. For those who do not qualify for a free vaccine, the RSV vaccine can be purchased with a prescription. Consult your healthcare provider to learn where you can access the vaccine.

The RSV vaccine can be given at the same time as other seasonal vaccines, such as influenza and/or Covid vaccines. Getting them together is recommended for added convenience and to help protect you better during the respiratory season.

How RSV spreads

RSV is very contagious and is spread by infected individuals in the same way as the common cold and other respiratory illnesses: 

  • through contact with droplets containing the virus after someone coughs or sneezes
  • through close contact (less than 2 metres apart) from someone with the infection who is coughing or sneezing

Once exposed to the virus, it can take 2 to 8 days before a person starts having symptoms. Individuals with an RSV infection are usually contagious for up to 8 days following infection and may spread the virus starting one to two days before they become visibly sick. Children are often exposed to and infected with RSV outside the home, such as in school or childcare centres, and can then transmit the virus to other members of the family. Reinfection is common and can happen at any age.

As is the case with other respiratory illnesses, RSV infections occur typically during the late fall into spring in Canada.

Symptoms of RSV

Symptoms of an RSV infection are similar to those of a cold or flu, and include:

  • cough
  • runny nose
  • wheezing
  • fever
  • production of large amounts of phlegm
  • decreased feeding or drinking
  • a decrease in energy
  • irritability

Most RSV symptoms will improve within a few days. However, parents of young children should seek medical attention if their child has trouble breathing (working hard to breathe, breathing faster than normal, pale skin, lips that look white or blue, asthma or wheezing), is not drinking enough fluids, or is experiencing worsening symptoms. Adults who are experiencing any of these signs should also seek immediate medical attention.

If your child becomes ill

Unfortunately, there is no specific medication to treat RSV infections and the bronchiolitis they may cause, as antibiotics aren’t effective against RSV. Treatment is therefore limited to managing symptoms. For tips on how you can manage your child’s symptoms, see How to treat someone with RSV.

Young children with RSV can usually be treated at home as long as:

  • they’re breathing comfortably
  • their skin doesn’t look blue
  • they’re drinking and urinating as usual

It’s crucial that babies drink enough fluids to prevent dehydration (loss of body fluids). If your baby is having trouble drinking, try to clear nasal congestion gently with a bulb syringe or with saline (salt water) nose drops. Because dehydration in babies and young children can be dangerous, it’s important to recognize the signs of dehydration, which include:

  • less frequent urination (fewer than eight wet diapers per day in babies)
  • no tears when crying
  • dry or sticky mouth
  • weight loss
  • extreme thirst

If your baby has signs of dehydration, worsening symptoms, or is having trouble breathing (working hard to breathe, breathing faster than normal, pale skin, lips that look white or blue, asthma or wheezing), seek medical care immediately. 

More information