• Respiratory Syncytial Virus (RSV) Vaccines and Therapeutics

    Respiratory syncytial virus (RSV) is a common virus that affects the lungs, making breathing difficult. It is also more common in the spring and fall seasons.  The virus is common in children under 2 years, though people of all ages can get it. Illness caused by RSV is often more severe for young and premature infants, as well as older adults with poor health. 

    While most children who contract RSV experience mild symptoms, the CDC estimates that each year, between 58,000 and 80,000 children younger than age 5 years are hospitalized due to RSV infection.  

    Adults at the highest risk for severe RSV illness include:

    • Older adults
    • Adults with chronic heart or lung disease
    • Adults with weakened immune systems
    • Adults living in nursing homes or long-term care facilities. 

    CDC estimates that RSV causes approximately 60,000-160,000 hospitalizations and 6,000-10,000 deaths among older adults every year.

    CDC Recommendations

    2023-2024 Respiratory Virus Season Interim CDC Recommendation to Protect Infants from Respiratory Syncytial Virus (RSV): Limited Availability of Nirsevimab

    In the context of limited supply during the 2023–2024 RSV season, CDC recommends prioritizing available nirsevimab 100mg doses for infants at the highest risk for severe RSV disease — i.e., young infants (age <6 months) and infants with underlying conditions that place them at highest risk for severe RSV disease.

    Recommendations for using 50mg doses remain unchanged at this time.

    Avoid using two 50mg doses for infants weighing ≥5 kilograms (≥11 pounds) to preserve supply of 50mg doses for infants weighing <5 kilograms (<11 pounds). Clinicians should be aware that some insurers may not cover the cost of two 50mg doses for an individual infant.

    CDC further recommends that clinicians suspend using nirsevimab in palivizumab-eligible children aged 8-19 months for the 2023-2024 RSV season. These children should receive palivizumab per American Academy of Pediatrics (AAP) recommendations. Nirsevimab should continue to be offered to American Indian and Alaska Native children aged 8-19 months who are not palivizumab-eligible and who live in remote regions, where transporting children with severe RSV for escalation of medical care is more challenging or in communities with known high rates of RSV among older infants and toddlers.

    Prenatal care clinicians should discuss potential nirsevimab supply concerns when counseling pregnant people about RSVpreF vaccine as maternal vaccination is effective and will reduce the number of infants requiring nirsevimab during the RSV season.

    Additional background information and recommendations for healthcare providers can be found at the CDC Health Alert Network.

    ACIP and AAFP Recommendations

    The AAFP RSV recommendations for pregnant people and adults 60 years and older:

    • The bivalent RSVpreF maternal RSV vaccine for pregnant people during 32 through 36 weeks gestation, using seasonal administration, to prevent RSV lower respiratory tract infection in infants.
    • Adults 60 years of age and older may receive a single dose of Respiratory Syncytial Virus (RSV) vaccine, using shared clinical decision-making. The AAFP's recommendation is consistent with recommendations from the Advisory Committee on Immunization Practices (ACIP) and the CDC, which have both endorsed use of new RSV vaccines for people ages 60 years and older. Patients over 60 should talk to their family physician or other clinician about whether or not RSV vaccination is right for them.