Respiratory Syncytial Virus Infection (RSV)

Respiratory syncytial virus (RSV) is a common infection caused by a virus. Infections are most common in the fall and winter months.source: ¹ RSV is highly contagious. Symptoms may include runny nose, decreased appetite, coughing, sneezing, and wheezing. In very young infants, symptoms can include irritability, decreased activity, eating or drinking less, and apnea (pauses in breathing for more than 10 seconds).source: ^2,source: ^3,source: ⁴

RSV spreads both through droplets in the air and through direct contact. Direct contact with RSV can occur when kissing the face of a child infected with RSV. When a person touches a surface that has RSV on it, and then touches their eyes, nose, and or mouth, they can become infected. Nearly all children have an RSV infection before they are 2 years old. Repeat RSV infections are common at all ages.source: ⁵

Even though RSV infections are usually mild, and most people recover in 1–2 weeks, they can be severe and affect the lower lung.source: ² Infants, especially those under 6 months, as well as some young children and older adults, are more likely to get very sick from RSV.source: ¹ Infants and young children at greatest risk for serious illness from RSV include:

• Premature infants
• Infants up to 12 months, especially those 6 months and younger
• Children under 2 years with chronic lung or heart disease
• Children with weakened immune systems
• Children with conditions that make it difficult for them to swallow or clear mucussource: ⁶

There are options to reduce the risk of severe RSV in infants and young children. The RSV preventive antibody (nirsevimab) is available for babies and some young children to protect them from severe RSV.source: ⁶ Antibodies are proteins that the body’s immune system uses to fight off harmful germs.source: ⁷ All babies younger than 8 months old who are born during or entering their first RSV season can receive nirsevimab.source: ^6,source: ⁸ An RSV maternal vaccine (Pfizer ABRYSVO) is also available for pregnant mothers who are at 32–36 weeks of pregnancy to pass on protection to their baby.source: ⁶

Learn more about who is at high risk for RSV and immunizations to protect infants and then talk with your child’s health care provider.

RSV can cause serious health problems in infants. In fact, it is the leading cause of infant hospitalization in the United States.source: ⁹ RSV causes swelling or inflammation of the small airways in the lungs and lung infections.source: ¹ Each year, more than 2 million children younger than 5 years old need to see a doctor or other health care provider for RSV.source: ¹⁰ Up to 80,000 children are hospitalized from the disease each year.source: ¹⁰

To prevent severe RSV disease in infants, CDC recommends either RSV vaccination during pregnancy or infant immunization with an RSV preventive antibody.source: ⁹

The most common side effects reported during clinical trials of the RSV preventive antibody were a rash and soreness, redness, or swelling at the injection site. If there are side effects, they are usually mild. Severe side effects are rare.source: ⁶ Learn more about RSV immunization side effects.

Infants under 8 months old who are born during or entering their first RSV season are recommended to receive an RSV preventive antibody immunization. Some children up to 19 months old who are also at risk for severe disease through their second RSV season may also need the RSV preventive antibody immunization.source: ^6,source: ¹³ An RSV preventive antibody is available to infants and some young children from October through March. Newborns can get the immunization before they leave the hospital or at a well-baby checkup.source: ¹³ Infants who are born at least 2 weeks after their mother gets an RSV vaccine at 32–36 weeks pregnant during September through January will not need the RSV preventive antibody except in rare circumstances.source: ⁸

RSV vaccination is recommended for people who are pregnant if they are 32–36 weeks pregnant during September through January in most of the United States.source: ⁸ Learn more about RSV vaccines or immunization.