Viral Update: Illness and Volume Trends, and Helpful Resources for Our Community

Our goal is to share information and resources with our larger community as we all work together to care for patients facing viral illnesses.

Washington State Department of Health (DOH) Announces Extension of RSV Season

RSV activity started later than usual this season and remains elevated. In response, the Washington Department of Health has extended the recommended RSV immunization window for infants through April 30, 2026. Providers should assess all patients for eligibility and administer RSV Monoclonal Antibody products before the deadline. Please review the WA DOH Provider Alert for additional details.

Viral Trends and Hospital Volumes

• ED Volumes: ED volumes increased from last week in part due to an increase in Influenza B. The combination of rising Influenza B activity, persistent RSV, seasonal coronavirus and HMPV will contribute to a high census for the foreseeable future, likely through April and into early May.
• Measles: The 2026 U.S. confirmed case count is 1,575. 2025 was the worst measles year since 1991 and 2026 continues to see increases in cases. Multiple outbreaks are ongoing, driven by lower vaccination rates.
• Influenza: Influenza activity locally continues to be high but below peak. At the national and local level, Influenza B has taken over from Influenza A as the dominant virus.
• RSV: RSV positives are high but below peak.
• SARS-CoV-2: Local wastewater and ED data show COVID-19 activity remains low.
• Mpox: Mpox testing is available at Seattle Children’s – if you feel your patient may have Mpox and want them tested, please call Mission Control at 206-987-8899.  
• Other Respiratory Viruses: Rhino/enterovirus remains the most common non-influenza/RSV positive. This channel represents multiple virus strains and does not include all enteroviruses. Seasonal coronaviruses are rising. These viruses usually contribute to our late winter or early spring respiratory season.
• Mycoplasma: Mycoplasma activity remains low, with a <1% positivity rate last week.
• Pertussis: Activity is down after two years of increased positivity at both the state and national level. The national count this year is lower than at the same time last year. Locally, we continue to see 0 to 2 positives per week. Continue to encourage vaccination.
• Norovirus and Rotavirus: Norovirus and rotavirus activity remains high.

Special Pathogens Team Update

Seattle Children’s has a special pathogens team that is continuously monitoring worldwide outbreaks to keep our staff, patients and community providers informed.

A suspected outbreak of viral hemorrhagic fever is being investigated in the Democratic Republic of the Congo. The outbreak of Nipah virus disease in India continues. There is no additional information available at this time, but we will continue to monitor.

A little information about Nipah virus:

• The virus: Nipah is a paramyxovirus that causes severe encephalitis and pneumonia.
• Incubation period: Typically, 4 to 14 days.
• The illness: Sometimes classified with viral hemorrhagic fevers due to its severe, systemic nature and potential for hemorrhage.
• Transmission: Spread via fruit bats, pigs or human-to-human contact.
• Fatality rate: Estimated between 40% and 75%.
• Symptoms: Fever, headaches, vomiting, sore throat and rapidly progressing encephalitis.

If you are treating a patient with recent (within the last month) travel to areas affected by hemorrhagic fevers and suspect a related illness, please contact your local public health department immediately.

If you are referring an ill patient that needs urgent evaluation to Seattle Children’s, please call Mission Control at 206-987-8899 before sending the patient.

Measles Resources

• Webinar Recording: Measles Community Response
• Measles One-Pager for Healthcare Providers (AAP)
• Measles - For Healthcare Professionals (CDC)
• Measles Specimen Collection Instructions for RT-PCR (DOH)
• Measles Specimen Collection Instructions for Serology (DOH)
• Immunization Schedules (CDC)
• Safety Information for Measles, Mumps, Rubella (MMR) Vaccines (CDC)
• Recognizing Measles in Your Patients (Pediatric Pandemic Network)
• Vitamin A and Measles Vaccine Talking Point (Pediatric Pandemic Network)
• Measles FAQ for Families & Caregivers (Pediatric Pandemic Network)

How You Can Help

• To help maintain ED volumes, consider reminding families of your clinic’s resources and procedures for urgent and after-hours patient needs to help direct them to the most appropriate site of care.
• Encourage families to review our ED vs. Urgent Care guide to find the most appropriate care setting – we have options for in-person and virtual urgent care, orthopedic urgent care, and psychiatric urgent care.
• Families should be prepared that, if viral testing is deemed clinically appropriate, it will typically be performed using a panel that identifies only influenza, RSV, and COVID-19.
• Before sending your patient to the ED, contact our Mission Control team with as much notice as possible at 206-987-8899. This helps us plan for your patient’s arrival, especially if there are concerns for communicable diseases.

Additional Resources

• View the respiratory virus data dashboard for the latest Seattle/King County trends for COVID, RSV and influenza-related ED visits.
• Read the situational summary on H5 Bird Flu to stay updated on the current Highly Pathogenic Avian Influenza A(H5N1) outbreak.
• View these resources on vaccine guidance for the most current COVID vaccination recommendations.
• Review the latest viral activity on the National Respiratory and Enteric Virus Surveillance System dashboard.