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Respiratory Syncytial Virus (RSV)

Information for the General Public

Information for Healthcare Providers

On October 23, 2023, CDC released a health advisory notice to communicate interim recommendations regarding the limited supply of nirsevimab, the new preventive antibody to protect infants against severe RSV.

Read more: Limited Availability of Nirsevimab in the United States—Interim CDC Recommendations

Current Disease Trends

Additional Resources


Current Trends


Information for General Public

What is RSV?

Respiratory syncytial (sin-SISH-uhl) virus, or RSV, is a common seasonal respiratory virus that usually causes mild, cold-like symptoms. RSV season usually starts in the fall and peaks in the winter. Most people recover in a week or two, but RSV can cause serious illness. Infants and older adults are more likely to develop severe RSV and need hospitalization. People are typically infected with RSV for the first time as an infant or toddler and nearly all children are infected before their second birthday. However, repeat infections may occur throughout life, and people of any age can be infected.

What are the usual symptoms of RSV?

People usually show symptoms of 4 to 6 days after getting infected. The symptoms of RSV infection include

  • Runny nose
  • Coughing
  • Sneezing
  • Fever
  • Wheezing
  • Decrease in appetite

These symptoms usually appear in stages and not all at once. In very young infants with RSV, the only symptoms may be irritability, decreased activity, and breathing difficulties.

How is RSV spread?

RSV can spread when:

  • You get virus droplets from an infected persons’s cough or sneeze in your eyes, nose, or mouth
  • You have direct contact with the virus, like kissing the face of a child with RSV
  • You touch a surface that has the virus on it, like a doorknob, and then touch your face before washing your hands

People infected with RSV are usually contagious for 3 to 8 days and may become contagious a day or two before they start showing signs of illness. However, some infants, and people with weakened immune systems, can continue to spread the virus even after they stop showing symptoms, for as long as 4 weeks.

How do I prevent RSV infection?

RSV immunizations are recommended for these groups only:

  • Two RSV vaccines (Arexvy by GSK and Abrysvo by Pfizer) have been licensed by FDA and recommended by CDC for adults ages 60 and older, using shared clinical decision-making.
  • One RSV vaccine (Abrysvo by Pfizer) has been licensed and recommended during weeks 32 through 36 of pregnancy to protect infants.
  • An RSV preventive antibody has been licensed and recommended for infants and some young children.

Measures that everyone can take to protect themselves and limit the spread of RSV include:

  • Stay home when sick.
  • Cover your coughs and sneezes with a tissue or your shirt sleeve, not your hands.
  • Wash your hands often with soap and water for at least 20 seconds.
  • Avoid touching your face with unwashed hands.
  • Avoid close contact with others, such as kissing, shaking hands, and sharing cups and eating utensils.
  • Clean frequently touched surfaces such as doorknobs and mobile devices.

How do I treat RSV infection?

Antiviral medication is not used to fight infection. Most RSV infections go away on their own in a week or two. However, RSV can cause severe illness in some people.

  • Manage fever and pain with over-the-counter fever reducers and pain relievers, such as acetaminophen or ibuprofen. (Never give aspirin to children.)
  • Drink enough fluids. It is important for people with RSV infection to drink enough fluids to prevent dehydration (loss of body fluids).
  • Talk to your healthcare provider before giving your child nonprescription cold medicines. Some medicines contain ingredients that are not good for children.
  • If you or someone you are caring for is worsening, particularly those at risk for severe RSV disease, talk to your healthcare provider and or seek prompt medical attention.

Who is at risk for severe RSV disease?

The two groups at risk for severe RSV are infants and older adults.

Among infants those at greatest risk are:

  • Premature infants
  • Infants up to 12 months, especially those 6 months and younger
  • Children younger than 2 years with chronic lung disease or congenital (present from birth) heart disease
  • Children with weakened immune systems
  • Children who have neuromuscular disorders, including those who have difficulty swallowing or clearing mucus secretions

Among older adults those at greatest risk are:

  • Older adults
  • Adults with chronic heart or lung disease
  • Adults with weakened immune systems
  • Adults with certain other underlying medical conditions
  • Adults living in nursing homes or long-term care facilities


Information for Healthcare Providers

Laboratory Testing

Testing for RSV is commonly available from commercial laboratories additionally approved point-of-care (POC) testing is available from some manufacturers. The most commonly used types of RSV clinical laboratory tests are:

  • Real-time reverse transcription-polymerase chain reaction (rRT-PCR), which is more sensitive than culture and antigen testing
  • Antigen testing, which is sensitive in children but less sensitive in adults

Less commonly used tests include:

  • Viral culture
  • Serology, which is usually only used for research and surveillance studies

Some tests can differentiate between RSV subtypes (A and B), but the clinical significance of these subtypes is unclear. Consult your laboratorian for information on what type of respiratory specimen is most appropriate to use.

Vaccines for Older Adults

New RSV vaccines are available for adults 60 and older. CDC recommends that adults 60 and older may receive a single dose of RSV vaccine, using shared clinical decision-making. The decision to vaccinate an individual patient should be based on a discussion between the healthcare provider and the patient. It may be informed by the patient’s risk of severe RSV disease and their characteristics, values, and preferences; the healthcare provider’s clinical discretion; and the characteristics of the vaccine.

Healthcare providers should be aware of underlying conditions that may increase the risk of severe RSV illness, and who might be most likely to benefit from these new vaccines.

RSV vaccine is recommended as a single dose. Studies are ongoing to determine whether (and if so, when) revaccination may be needed over time.

Maternal Vaccines for Pregnant People

A new RSV vaccine is recommended for pregnant people who are 32–36 weeks pregnant with seasonal administration during September–January in most of the continental United States. In jurisdictions with seasonality that differs from most of the continental United States (e.g., Alaska, jurisdictions with tropical climates), providers should follow state, local, or territorial guidance on timing of administration.

This vaccine provides protection against severe RSV illness to the recipient’s baby for up to 6 months of age. However, the infant’s protection will wane over time. Healthcare providers of pregnant people should provide information on both maternal vaccines and infant monoclonal antibody products and consider patient preferences when determining whether to vaccinate the pregnant patient or to not vaccinate and rely on administration of nirsevimab to the infant after birth.

Monoclonal Antibody Products for Infants and Young Children

Nirsevimab (Beyfortus) is a monoclonal antibody product that can protect infants and some young children from severe RSV disease. It is recommended for:

  • Infants under 8 months old born during – or entering – their first RSV season (typically fall through spring) if their mother did not receive an RSV vaccine, it is unknown if their mother received an RSV vaccine, or the mother received a vaccine but the infant was born <14 days after vaccination
  • Nirsevimab can be considered in rare circumstances even though the mother received an RSV vaccine when, per the clinical judgment of the healthcare provider, the potential incremental benefit of administration is warranted:
    • Pregnant people who may not mount an adequate immune response to vaccination (e.g., people with immunocompromising conditions) or have conditions associated with reduced transplacental antibody transfer (e.g., people living with HIV infection)
    • Infants who have had cardiopulmonary bypass leading to loss of RSV antibodies
    • Infants with substantially increased risk for severe RSV disease (e.g., hemodynamically significant congenital heart disease, intensive care admission, and requiring oxygen at discharge)
  • Some children between the ages of 8 and 19 months who are at increased risk of severe RSV disease before their second RSV season. These include:
    • Children who have chronic lung disease of prematurity who required medical support (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) any time during the 6-month period before the start of the second RSV season
    • Children with severe immunocompromise
    • Children with cystic fibrosis who have severe disease
    • American Indian and Alaska Native children

Nirsevimab is administered by intramuscular injection. It is long-acting, providing protection for at least 5 months (the average length of one season), and only one dose is recommended for an RSV season. However, immune protection will wane over time. Another monoclonal antibody, Palivizumab (Synagis), is recommended by the American Academy of Pediatrics (AAP) for administration to infants and young children who are at increased risk of severe RSV disease based on gestational age and certain underlying medical conditions. It is given in monthly intramuscular injections during RSV season. AAP has provided considerations for the 2023–2024 RSV season with regard to palivizumab versus nirsevimab administration for high-risk infants during the same RSV season.


Additional Resources


Page Last Updated: 12/7/2023