Forecast
Seasonal activity for influenza, RSV, and COVID-19 is expected to increase in the coming weeks and months, and projections for this upcoming season suggest a similar or lower combined peak hospitalization burden for influenza, RSV, and COVID-19 compared with last year. Scenario modeling predicts a milder influenza season compared with last year and a milder COVID-19 season compared with this summer, assuming immunization uptake proceeds in line with historical trends.
During the 2024-2025 high severity influenza season, an
increase in severe pediatric neurologic complications was seen throughout the United States with numerous cases occurring in California, primarily in unimmunized children. Influenza-associated encephalopathies including acute necrotizing encephalitis cause severe morbidity and high mortality in those that are affected. CDPH urges providers to stay vigilant and report cases of severe unexpected complications this respiratory virus season.
CDPH urges healthcare providers to prepare for increases in respiratory virus activity to maximize prevention and reduce severe disease and healthcare impacts.
Stay aware of respiratory virus activity in your community by visiting the CDPH Respiratory Virus Dashboard. Influenza, RSV, and COVID-19 pose the greatest risk for young children, older adults, and people with certain medical conditions. Providers should identify patients at higher risk and prioritize prevention and therapeutic strategies for these populations.
Recommendations
Respiratory Virus Prevention
Talk to your patients about respiratory virus infection prevention and control measures including immunizations, hand and respiratory hygiene, well-fitted masks, improving airflow or ventilation, and staying home when sick. Encourage testing and treatment in populations at risk of severe disease who are eligible for respiratory virus therapeutics.
Immunizations
Immunizations are a critical tool for prevention of influenza, RSV, and COVID-19 infections, especially in
populations at higher risk for severe disease. Offer vaccines to all
eligible persons at every opportunity including weekend and evening clinics, during sports physicals, or sick visits. For the most current information on respiratory virus immunizations, visit CDPH's
Public Health for All page.
Download the printable PDF.
Children
| - All 6–23 months
- All 2–18 years with risk factors or never vaccinated against COVID-19
- All who are in close contact with others with risk factors [1]
- All who choose protection [1]
| - All 6 months and older
| - All younger than 8 months [2]
- All 8–19 months with risk factors
|
Pregnancy
| - All who are planning pregnancy, pregnant, postpartum, or lactating
| - All who are planning pregnancy, pregnant, postpartum, or lactating
| - 32–36 weeks gestational age [3]
|
Adults
| - All 65 years and older
- All younger than 65 years with risk factors
- All who are in close contact with others with risk factors
- All who choose protection
| | - All 75 years and older [3]
- All 50–74 years with risk factors [3]
|
[1] COVID-19 vaccine is available for persons 6 months and older.
[2] Protect infants with either prenatal RSV vaccine or infant dose of nirsevimab or clesrovimab.
[3] RSV vaccination during pregnancy or for adults is currently recommended once rather than annually.
Immunizations are recommended for healthcare workers and other people who live with or care for people at higher risk of serious illness from respiratory viruses. This is especially true for people who work in long-term care facilities which are home to many of the people most vulnerable to respiratory viruses. For talking points on immunizations in long-term care facilities, see CDPH’s
Flu, COVID-19, and RSV Talking Points for Long-Term Care Facilities.
Testing
Healthcare providers:
Test patients with suspected respiratory virus infections to differentiate the type of infection when treatment is indicated, including those at higher risk for severe infection, those with severe or progressive respiratory illness, and those with potential exposures to animals infected with avian influenza A(H5N1). In hospitalized patients, molecular assays are recommended when testing for RSV, influenza, and SARS-CoV-2; testing for other respiratory viruses should also be considered since other viruses and co-infections can cause severe illness.
Influenza testing by rRT-PCR should be encouraged in situations where sequencing or subtyping may be needed, including:
Specimens should be collected within the first 24–72 hours of symptom onset and no later than 5 days after symptom onset. For patients suspected of having avian, variant, or novel influenza, specimens may be collected no later than 10 days after symptom onset. For ICU/hospitalized cases, specimens should be submitted to a public health laboratory as soon as possible, preferably within 24-48 hours of collection.
Influenza rRT-PCR testing and further subtyping is available at the CDPH Viral and Rickettsial Disease Laboratory (CDPH-VRDL) and at 24 Respiratory Lab Network (RLN) Public Health Laboratories (PHLs). Please contact your
your local public health laboratory (PHL) for information on specimen submission instructions. send appropriate specimens to your PHL. Contact for information on specimen submission. Your PHL can contact the
CDPH Viral and Rickettsial Diseases Laboratory (VRDL) for additional assistance when needed.
Information to assist healthcare providers about when to consider respiratory virus testing is available at
Clinical Guidance for Hospitalized and Non-Hospitalized Patients When SARS-CoV-2 and Influenza Viruses are Co-Circulating | Influenza (Flu) | CDC, Information for Clinicians on Influenza Virus Testing, Respiratory Syncytial Virus for Healthcare Professionals, and Overview of Testing for SARS-CoV-2.
Laboratories
Hospitals and clinical laboratories should ensure that influenza A positive samples from severely ill patients are subtyped either in the clinical laboratory or sent to a public health laboratory for subtyping.
Clinical and commercial laboratories should immediately report any samples that are influenza A positive and for which subtyping was attempted but did not identify a seasonal influenza A subtype (i.e. H1 or H3) to the local health department of the patient's residence and urgently direct these samples to a local public health laboratory for additional testing.
Therapeutics
Treatment with COVID-19 and influenza antivirals decreases the risk of serious illness, hospitalization, and death. Evaluate symptomatic patients and offer therapeutics
as soon as possible (ideally within first 48 hours) to eligible patients, especially those at higher risk for severe disease or who may transmit to high-risk contacts. Paxlovid is the first line therapy for mild to moderate COVID-19 in the outpatient setting. Oseltamivir is the first line therapy for any patient with suspected or confirmed influenza who is at higher risk for influenza complications; who is hospitalized; who may transmit to high-risk contacts; or who has severe, complicated, or progressive illness.
Preventive antibodies are available for some people who are moderately or severely immunocompromised for additional protection against COVID-19 and RSV. Antiviral medications can also be used to prevent against influenza.
Visit the CDPH Healthcare Professionals Hub for more information about therapeutics. For additional information on available therapeutics, see:
Clinical Guidance for Outpatients With Acute Respiratory Illness at Higher Risk of Severe COVID-19 and/or Influenza, COVID-19 Treatment Clinical Care for Outpatients, Influenza Antiviral Medications: Summary for Clinicians, and AAP's
Respiratory Syncytial Virus (RSV) Prevention.
Infection Prevention and Control Measures
During periods of increased transmission of respiratory viruses and in the event of a healthcare facility outbreak, healthcare facilities should implement source control masking policies as described in CDPH's Guidance for Face Coverings as Source Control in Healthcare Settings and in accordance with their local health department recommendations or requirements.
Healthcare personnel working in hospitals and long-term care facilities (including skilled nursing facilities) should empirically apply appropriate
Transmission-Based Precautions, including placement in a single room, when examining a patient with known or suspected respiratory infection. Precautions should be based on the clinical syndrome and the likely etiologic agents (e.g., which respiratory viruses are circulating in the community, contact with someone known to have a specific respiratory viral infection) and modified once the pathogen is identified or a transmissible infectious etiology is ruled out. If the etiology is uncertain and SARS-CoV-2 is considered possible, precautions should generally follow those
recommended by SARS-CoV-2 until this diagnosis is excluded. See Appendix A in the CDC Guideline for Isolation Precautions for syndromic and pathogen-specific recommendations for Transmission-Based Precautions, including guidance on the recommended duration of isolation. See also
CDC Guidance on Preventing Transmission of Viral Respiratory Pathogens in Healthcare Settings.
For more information on infection prevention and control of respiratory viruses in skilled nursing facilities, healthcare providers may visit the CDPH Recommendations for Prevention and Control of COVID-19, Influenza, and Other Respiratory Viral Infections in California Skilled Nursing Facilities (PDF).
Respiratory Virus Season Resources