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 two RSV protection options that are currently available in Canada:
- An RSV immunization for babies and young children
- An RSV vaccine for pregnant individuals to help protect their baby after birth
This information is based on the official Product Monographs and the National Advisory Committee on Immunization (NACI) guidance. It does not replace a conversation with your healthcare provider. Always talk to your provider about what’s right for you or your baby.
Infant RSV Immunization
This immunization is a long-acting antibody that is given as a single injection. It helps protect babies from getting very sick with 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
- Skin rash
- Mild fever
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 it?
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 nirsevimab in the past
- Are known to be severely allergic to any or all ingredients in the injection
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, or immune system problems
- Your baby has a rare “protein-losing” condition or other complex medical issues
Maternal RSV Vaccine
This is a vaccine 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 RSV in the first months of life.
In Canada, this vaccine is offered between 32 and 36 weeks of pregnancy.
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
- Feeling tired or low energy
- Headache
- Muscle aches
- Joint pain
- Nausea
These side effects can often be managed with rest, fluids, and over-the-counter medicines, if recommended by your provider.
Less common side effects:
A smaller number of people may notice:
- Redness or swelling at the injection site
If any of these happen after vaccination, call 9-1-1 or go to the nearest emergency department.
Pregnancy-related safety information:
Health Canada currently recommends that this vaccine be used only between 32–36 weeks of pregnancy. 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 immunization: Full safety and prescribing information
- Maternal vaccine: Full safety and prescribing information
National Advisory Committee on Immunization (NACI) statements on RSV protection for infants and pregnancy.