The respiratory syncytial virus (RSV) season has been extended through April 30, 2026. Please continue to administer nirsevimab or clesrovimab to all eligible patients through April 30th.
Current Situation
RSV activity in Washington began later than usual this season, with emergency department visits in the state reaching the activity threshold in December 2025, compared to October and November in prior seasons. RSV activity and hospitalization rates in young children in Washington remain elevated; providers can view the WA DOH Respiratory Illness Dashboard for more details.
This delayed and prolonged RSV season mirrors national trends this year. It is possible that RSV activity may continue into April nationwide.
With RSV activity remaining elevated this season, Washington Department of Health (DOH) has extended the recommended administration period for RSV immunization for infants through April 30, 2026.
Actions Requested
Healthcare providers in Washington are requested to do the following:
IDENTIFY and Immunize
- Assess every patient for RSV immunization eligibility and administer nirsevimab or clesrovimab before April 30, 2026.
- All infants under 8 months of age are eligible if:
- they have not already received nirsevimab or clesrovimab,
- have no contraindications
- were not protected through maternal RSV vaccination at least 2 weeks before birth.
- Higher-risk infants 8-19 months in their 2nd RSV season should also be assessed and administered RSV immunization.
NOTIFY
- There are no new reporting requirements associated with this extension.
MANAGE SUPPLY
- DOH distribution plan for ordering RSV Monoclonal Antibodies during the extended season:
- Ordering will be limited to birthing hospitals and Tribal clinics.
- Childhood Vaccine Program providers should place orders of RSV monoclonal antibodies using the Immunization Information System (IIS) by March 31, 2026.
- All providers should continue administering any nirsevimab doses they currently have on hand to eligible infants through April.
- Providers outside of birthing hospitals and Tribal clinics who need doses may contact DOH to facilitate a transfer: WAChildhoodVaccines@DOH.WA.GOV
- Ordering will be limited to birthing hospitals and Tribal clinics.
ADVISE
- Counsel families of eligible infants that RSV remains the leading cause of infant hospitalization in the United States, and that RSV immunization (monoclonal antibody) is available and recommended through April 30, 2026.
- Patients can find more information about RSV and RSV prevention at WA DOH’s RSV webpage.
Background
Respiratory Syncytial Virus (RSV) is a common respiratory virus that usually causes mild, cold-like symptoms. However, RSV can cause severe illness leading to hospitalization and even death in some groups of people, including infants and older adults. RSV is the leading cause of infant hospitalization in the United States.
In Washington, the 2025-2026 RSV season had a delayed onset, with elevated activity starting in December 2025, more than a month later than previous seasons. RSV hospitalization rates among infants under 1 year have been the highest of any age group this season, peaking at approximately 26 per 100,000 in January 2026, with rates still elevated as of late February. The delayed start to the Washington RSV season and continued elevated activity into late winter are consistent with patterns seen nationally.
Nirsevimab (Beyfortus) and clesrovimab (Enflonsia) are monoclonal antibody products that provide direct protection to infants against RSV. Unlike the maternal RSV vaccine, which is administered to pregnant individuals at 32–36 weeks gestation and requires a 1–2 month lead time before protecting the infant, RSV monoclonal antibodies are given directly to infants, which allow for greater flexibility in providing protection during seasons with late or prolonged RSV activity.
Resources
For more information about RSV and RSV immunization, please visit:
- Respiratory Syncytial Virus (RSV), DOH.
- Respiratory Illness Data Dashboard, DOH.
- RSV Prevention, American Academy of Pediatrics.
Contact
For questions about RSV immunization product ordering or dose transfers, contact the WA DOH Childhood Vaccines program: WAChildhoodVaccines@DOH.WA.GOV
For any other questions, please call Grays Harbor County Public Health at (360) 532-8631.