information for parents
RSV Protection: Side Effects & Safety
Like all medicines and vaccines, RSV protection options can cause side effects.
Not everyone will experience side effects, and when they do happen, they are usually mild and get better on their own. More serious side effects are rare, but they can occur.
This page explains some of the known benefits and risks of RSV protection options currently available in Canada. Depending on your province or territory, protection against RSV may include:
- A long-acting monoclonal antibody for infants
- An RSV vaccine given during pregnancy to help protect a baby after birth
This information is based on Health Canada-authorized Product Monographs and recommendations from the National Advisory Committee on Immunization (NACI). It does not replace a conversation with your healthcare provider. Always speak with your healthcare provider about what is appropriate for you or your baby.
Infant RSV Protection Through Monoclonal Antibodies
Two long-acting monoclonal antibodies are currently authorized in Canada to help protect infants against severe RSV disease during their first RSV season. These products are not vaccines. They provide ready-made antibodies that help protect babies from getting very sick from RSV in their first RSV season.
Common, usually mild side effects:
In studies, these types of reactions were uncommon and happened in a small number of babies. These side effects are generally short-lived and often get better on their own:
- Where the needle goes in (injection site)
- Redness
- Swelling or firmness
- Soreness or pain
- General
- Mild fever
- Mild skin rash
Rare, but more serious side effects:
Very rarely, babies can have an allergic reaction (anaphylaxis), including:
- Sudden difficulty breathing or wheezing
- Swelling of the face, lips, tongue, or throat
- Hives (raised, itchy rash) with other symptoms
- Collapse or becoming very floppy or hard to wake
These reactions are medical emergencies. If they occur, call 9-1-1 or go to the nearest emergency department.
Who might not be able to receive a monoclonal antibody?
Your baby’s healthcare provider will review your child’s medical history and decide if it is suitable. This immunization should not be given to babies who:
- Have had a severe allergic reaction (including anaphylaxis) to an RSV monoclonal antibody received in the past
- Are known to be severely allergic to any or all ingredients in the product
Special situations
Your health-care provider may be extra cautious and talk with you in more detail if:
- Your baby was born prematurely
- Your baby has serious heart, lung, kidney, immune system, or neurological conditions
- Your baby has a rare “protein-losing” condition or other complex medical issues that require ongoing specialist care
Maternal RSV Vaccine
An RSV vaccine may be given during pregnancy to help your body make RSV-fighting antibodies. These antibodies are passed to your baby before birth to help protect them from severe RSV disease in the first months of life.
In Canada, this vaccine is offered between 32 and 36 weeks of pregnancy. NACI recommends that RSVpreF may be considered from 28 to 36 weeks of gestation. Your healthcare provider can discuss the timing that is appropriate for your pregnancy. Always speak with your healthcare provider about what is appropriate for you or your baby.
Common, usually mild side effects:
Most side effects are short-term (1–3 days) and similar to other common vaccines:
- Where the needle goes in
- Pain or soreness
- Sometimes redness or swelling
- General
- Headache
- Muscle aches
These side effects can often be managed with rest, fluids, and over-the-counter medicines, if recommended by your provider.
Severe Side-Effects and what to do:
- Allergic reactions: swelling of the face, lips, tongue or throat, hives, difficulty breathing or swallowing, dizziness, which are signs and symptoms of hypersensitivity reactions.
If any of these happen after vaccination, call 9-1-1 or go to the nearest emergency department.
Pregnancy-related safety information
Your healthcare provider can discuss the timing that is appropriate for your pregnancy. Always speak with your healthcare provider about what is appropriate for you or your baby. Your pregnancy care provider will look at your full medical and pregnancy history and discuss the potential benefits and risks with you before vaccination.
Who should not receive this vaccine?
This vaccine is not recommended for people who:
- Have had a severe allergic reaction to a previous dose of this RSV vaccine
- Have a known serious allergy to any ingredient in the vaccine
If you have had serious reactions to other vaccines or injectable medicines in the past, make sure to tell your provider.
Product Monographs
Product monographs are technical documents. If you have any questions or would like detailed medical information, please consult your healthcare provider, who can review these documents with you:
- Infant immunizations: Full safety and prescribing information
- Nirsevimab Product Monograph (See page 27 for Patient Medical Information)
- Clesrovimab Product Monograph (See page 20 for Patient Medical Information)
- Maternal vaccine: Full safety and prescribing information (See page 36 for Patient Medical Information)
- National Advisory Committee on Immunization (NACI) statements on RSV protection for infants and pregnancy
Disclaimer: This website provides general information about RSV and awareness of available protection options only. It does not recommend, promote, or endorse any specific vaccines or products. For guidance tailored to you and your family, please consult a healthcare provider.
The materials presented are developed by Praxus Health and made possible with financial support from Merck Canada, Pfizer Canada, and Sanofi Canada. The sponsors did not participate in developing the editorial content. All content was developed, reviewed, and approved independently by Praxus Health to ensure balance and accuracy.