October 19, 2023

Current Situation

Last fall, California experienced a surge in cases of respiratory viral illnesses that strained health care facilities statewide. That unusually early and severe respiratory syncytial virus (RSV) season overwhelmed the pediatric critical care capacity of the healthcare system. This fall, the recent increase in RSV activity in the Southeastern U.S. likely indicates that a rise in RSV cases in the Western U.S. will soon follow. Implementing respiratory virus prevention and treatment measures now, including immunization, can minimize hospitalizations and death and preserve health care capacity in the following weeks and months. New options are available this year to mitigate severe RSV illness among infants and high-risk children.

Recommendations for Healthcare Providers

Recommend and offer RSV vaccination to pregnant persons.

• Pregnant people should receive a single dose of Pfizer’s bivalent RSVpreF vaccine (Abrysvo) during weeks 32 through 36 of pregnancy from September through January so that their babies are protected against severe RSV disease at birth.

Recommend and offer preventive monoclonal antibody products to infants and high-risk young children.

• One dose of nirsevimab (Beyfortus) is recommended for infants younger than 8 months of age who were born shortly before or are entering their first RSV season (typically fall through spring) if:
  • The mother did not receive RSV vaccine during pregnancy, or
  • The mother’s RSV vaccination status is unknown, or
  • The infant was born within 14 days of maternal RSV vaccination.
  • Except for special situations and populations, nirsevimab is not needed for infants younger than age 8 months born 14 or more days after maternal RSV vaccination.
• Nirsevimab is also recommended for the following children 8 through 19 months of age who are at increased risk for severe RSV disease shortly before or during their second RSV season:

• Children with 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 who are severely immunocompromised.
• Children with cystic fibrosis who have either:
  • Severe lung disease (previous hospitalization for pulmonary exacerbation in the first year of life or abnormalities on chest imaging that persist when stable) or
  • Weight-for-length that is <10th percentile.
• American Indian and Alaska Native children.

Children 8 months of age and older who are not at increased risk of severe RSV disease should not receive nirsevimab.

For infants born during RSV season, nirsevimab can be administered in the birth hospital or outpatient clinic. For infants born outside of the RSV season, administration should be targeted shortly before the start of their first RSV season. Nirsevimab should be offered to all age-eligible children throughout the RSV season who have not received a dose. In most places in the continental US, RSV season occurs between October through March. Providers may adjust administration schedules based on local RSV activity and epidemiology.

Availability

Supplies of RSVpreF vaccines and nirsevimab monoclonal antibody are slowly becoming available. Providers should consult with their normal immunization and pharmaceutical suppliers regarding availability and pricing.

Additional Information

• CDC Use of Nirsevimab for the Prevention of Respiratory Syncytial Virus Disease Among Infants and Young Children: Recommendations of the Advisory Committee on Immunization Practices — United States, 2023:https://www.cdc.gov/mmwr/volumes/72/wr/mm7234a4.htm.
• CDC RSV Vaccination for Pregnant People:https://www.cdc.gov/vaccines/vpd/rsv/hcp/pregnant-people.html#:~:text=CDC%20recommends%20a%20respiratory%20syncytial,pregnancy%20during%20September%20through%20January.
• CDPH Nirsevimab (Beyfortus) Now Available from VFC for Prevention of Severe RSV Disease in Young Children: https://eziz.org/assets/docs/VFC_Letters/2023Oct11NirsevimabPreventionSeriousRSV.pdf.
• CDPH AFL 23-30: Guidance for Response to Anticipated Adult and Pediatric Surges in Respiratory Virus Transmission https://www.cdph.ca.gov/Programs/CHCQ/LCP/Pages/AFL-23-30.aspx.
• CDPH Nirsevimab (Beyfortus) Guide to Prevent Severe RSV in Infants and Toddlers: https://eziz.org/assets/docs/IMM-1480.pdf.
• California Vaccines for Children (VFC) Program: https://eziz.org/vfc/
• Printable Copy of this Health Advisory

Health Alert:  Warrants immediate action or attention.  Health Advisory:  Provides information for a specific incident or situation; may not require immediate action.  Health Update:  Provides updated information regarding an incident or situation; unlikely to require immediate action.

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