The Washington State Department of Health has extended the RSV immunization season through April 30, 2026, asking healthcare providers to continue offering monoclonal antibody treatments to eligible infants. The advisory applies to providers across the state, including those serving Thurston County families.
RSV activity this season started later than usual. Emergency department visits statewide didn't reach the alert threshold until December 2025, compared to October or November in previous years. Despite the delayed start, RSV activity and hospitalization rates in young children remain elevated.
All infants under 8 months are eligible for nirsevimab or clesrovimab if they have not already received the treatment, were not protected through maternal RSV vaccination at least two weeks before birth, and have no medical contraindications. Higher-risk infants between 8 and 19 months in their second RSV season may also be eligible for nirsevimab.
RSV is the leading cause of infant hospitalization in the United States. Parents of eligible infants are encouraged to contact their child's healthcare provider before April 30 to confirm whether the treatment is appropriate.