RSV is a seasonal virus.

That means that you are more likely to catch it during certain times of the year.

In most areas of the US, RSV season is similar to flu season.

It starts in the fall and ends in the spring. And like flu season, RSV season is different from year to year. It may also start and end at different times, depending on what part of the country you live in.

In the US: Severe RSV disease is the main cause of hospital stays for children under 1 year of age.

What else do I need to know about RSV disease?

  • RSV can spread as easily as the flu. Sneezing, coughing, and touching are all examples of how it spreads
  • In most cases, RSV causes symptoms like those of the common cold
  • For high-risk children, like premature babies or children with certain heart or lung diseases, it can cause serious lung infections

Why is protection from RSV important for your baby?

This video may help answer some of the questions you have about severe RSV disease, its impact on your high-risk baby, and why preventive therapy is important.


How does SYNAGIS work?

SYNAGIS is not a vaccine. It is an injection of antibodies. It can help the body fight off RSV. Each dose has enough antibodies to help protect your baby for about a month. So your baby should get a dose of SYNAGIS every 28 to 30 days during the RSV season.

To learn more about SYNAGIS, click here.

Remember to talk to your doctor if you have questions about SYNAGIS or your baby’s health.

Important Safety Information

Who should not receive SYNAGIS?

Children should not receive SYNAGIS if they have ever had a severe allergic reaction to it. Signs and symptoms of a severe allergic reaction could include itchy rash; swelling of the face; difficulty swallowing; difficulty breathing; bluish color of the skin; muscle weakness or floppiness; and/or unresponsiveness. If your child has any of these signs or symptoms of a severe allergic reaction after getting SYNAGIS, call your child’s healthcare provider or get medical help right away.

How is SYNAGIS given?

SYNAGIS is given as a monthly injection, usually in the thigh (leg) muscle, by your child’s healthcare provider. If your child has a problem with bleeding or bruises easily, an injection could cause a problem. Your child should receive their first injection of SYNAGIS before the RSV season starts, to help protect them before RSV becomes active. RSV season is usually fall through spring, but it may begin earlier or last longer in certain areas. When RSV is most active, your child will need to receive injections of SYNAGIS every 28-30 days to help protect them from severe RSV disease for about a month. Your child should continue to receive monthly injections of SYNAGIS until the end of RSV season. Your child may still get severe RSV disease after receiving SYNAGIS. If your child has an RSV infection, they should continue to get their monthly injections throughout the RSV season to help prevent severe disease from new RSV infections.

The effectiveness of injections of SYNAGIS given less than monthly throughout the RSV season has not been established.

What are the possible side effects of SYNAGIS?

Serious side effects include severe allergic reactions, which may happen after any injection of SYNAGIS and may be life-threatening or cause death. Call your child’s healthcare provider or get medical help right away if your child has any of the signs or symptoms of a serious allergic reaction. See “Who should not receive SYNAGIS?” for more information.

Common side effects of SYNAGIS include fever and rash.

These are not all the possible side effects of SYNAGIS.


SYNAGIS is a prescription medication that is used to help prevent a serious lung disease caused by respiratory syncytial virus (RSV) in children:

  • born prematurely (at or before 35 weeks) and who are 6 months of age or less at the beginning of RSV season
  • who have a chronic lung condition called bronchopulmonary dysplasia (BPD), that needed medical treatment within the last 6 months, and who are 24 months of age or less at the beginning of RSV season
  • born with certain types of heart disease and who are 24 months of age or less at the beginning of RSV season

It is not known if SYNAGIS is safe and effective:

  • to treat the symptoms of RSV in a child who already has RSV. SYNAGIS is used to help prevent RSV disease
  • in children who are older than 24 months of age at the start of dosing

You may report side effects related to AstraZeneca products by clicking here.