A seasonal injection to protect high-risk babies from severe RSV
Palivizumab
A monoclonal antibody given as a monthly injection during the RSV season to help protect high-risk babies from severe RSV illness.
What is Palivizumab?
Palivizumab is a specialist medicine used to help protect babies who are at high risk from respiratory syncytial virus (RSV), a common winter virus that can cause serious chest infections in vulnerable infants. It is a monoclonal antibody given as an injection into the muscle, usually once a month through the RSV season. It is not a vaccine: it gives ready-made, passive protection that lasts for a limited time, which is why repeat injections are needed across the season. It is used to prevent severe RSV rather than to treat an infection that has already started, and the most common effects are soreness where the injection is given and sometimes a fever.
Education and reference only. This is a plain-language guide to Palivizumab — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Palivizumab is a monoclonal antibody, a laboratory-made protein that recognises and sticks to respiratory syncytial virus (RSV). It is used to help protect babies who are at high risk of becoming seriously ill from RSV, such as those born very prematurely or with certain heart or lung problems. Unlike a vaccine, which teaches the body to make its own protection, palivizumab supplies ready-made antibodies directly, giving passive protection that wears off over time. It is given as an injection into the muscle, usually once a month during the RSV season, under the care of a specialist children's team.
How it works
Palivizumab works by coating the respiratory syncytial virus so it cannot easily infect the cells of a baby's airways, lowering the chance of a severe chest infection. Because the protection comes from the antibody itself rather than from the baby's own immune system, it only lasts while enough of the medicine is in the body. This is why it is given as repeated monthly injections through the RSV season, to keep protection topped up while the risk of catching the virus is highest. It helps prevent severe illness but does not stop a baby ever catching RSV, and it is not used to treat an infection that is already underway.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist medicine used in the UK to help protect babies at high risk of severe illness from respiratory syncytial virus (RSV) during the winter season.
Practical use
How to take Palivizumab
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given by a healthcare professional as an injection into the muscle, usually the thigh.
- Keep to the monthly injection appointments through the RSV season, as protection fades between doses.
- Try not to miss or delay doses, since a gap can leave the baby less protected during the season.
- It is used to help prevent severe RSV, not to treat an infection that has already started.
- Continue everyday measures such as handwashing and avoiding people with coughs and colds.
Weighing it up
Advantages & disadvantages of Palivizumab
Advantages
- Helps protect high-risk babies from severe illness caused by RSV during the winter season.
- Gives ready-made, immediate protection without waiting for the baby's own immune response.
- Given as a simple monthly injection through the season under specialist care.
Disadvantages
- Protection fades over time, so it must be repeated every month through the season.
- It is given as an injection, which can cause soreness and sometimes a fever.
- It prevents severe RSV but does not treat an infection that has already started.
Practical use
Good to know
The most important thing to understand is that palivizumab is a preventive medicine for the RSV season, not a vaccine and not a treatment for an infection that has already started. It works by giving ready-made antibodies that fade over time, so the monthly injections need to be kept up across the whole season to stay protected, and missing doses can leave a gap in protection. It is given into the muscle, usually the thigh, and the most common effects are soreness, redness or swelling at the injection site and sometimes a mild fever, which settle on their own. Serious allergic reactions are rare but possible, so the team watches for them. Good everyday measures, such as careful handwashing and keeping the baby away from people with coughs and colds, still matter alongside it.
Who should not take it / use with caution
- Babies who have had a serious allergic reaction to palivizumab should not be given it again.
- It is only used in babies assessed as high risk by a specialist team, not in all infants.
- It is given with care, and with monitoring, in babies who are unwell at the time of an injection.
Monitoring
- Checking the baby remains high risk and that the monthly injections are kept up through the season.
- Watching for injection-site reactions and any signs of an allergic reaction.
- Reviewing the baby's general health and chest at each visit.
Side effects
- Soreness, redness or swelling where the injection is given.
- A mild fever or being a little more irritable for a short time.
- Rarely, a serious allergic reaction, which needs urgent medical attention.
Key interactions
- There are few well-established routine medicine interactions, but tell the team about all the baby's medicines.
- It can usually be given around the time of routine childhood vaccinations, guided by the team.
- It is used alongside, not instead of, everyday measures to reduce the spread of infection.
Available as: A solution or powder made up for injection into the muscle.
Answers
Palivizumab: frequently asked questions
What is palivizumab used for?
It is used to help protect babies who are at high risk of severe illness from respiratory syncytial virus (RSV) during the winter season.
Is palivizumab a vaccine?
No. It is a monoclonal antibody that gives ready-made, passive protection that fades over time, which is why it is given as repeated monthly injections rather than as a one-off vaccine.
Why does my baby need an injection every month?
The protection comes from the antibody itself and wears off over time, so monthly injections keep protection topped up while the risk of catching RSV is highest.
Can it treat RSV if my baby already has it?
No. It is used to help prevent severe RSV, not to treat an infection that has already started, so a baby who is unwell with RSV needs other care.
What are the common side effects?
The most common effects are soreness, redness or swelling where the injection is given and sometimes a mild fever, which usually settle on their own.
Authoritative sources
- BNF
- NICE CKS
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