Influenza Activity During the 2024-2025 Influenza Season
The 2024-25 influenza season in the United States was considered highly severe with an estimate of at least 47-82 million symptomatic illnesses, 21-37 million medical visits, 610,000 – 1.3 million hospitalizations, and 27,000-130,000 deaths caused by influenza virus infection.
The predominant influenza viruses throughout the 2024-25 influenza season were influenza A(H1N1 pdm09) and A(H3N2); however, as activity declined, B/Victoria viruses began circulating as well. Most influenza viruses tested were in the same genetic subclade as, and antigenically similar to the vaccine reference viruses included in the season’s influenza vaccine. All the influenza viruses collected and tested for antiviral resistance by CDC from September 29, 2024 through May 17, 2025 were susceptible to zanamivir and the majority (>97.7%) were susceptible to Oseltamivir, Peramivir and Baloxivir.
Recommendations
Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2025–26 Influenza Season | MMWRhas been published. CDC recommends annual influenza vaccination for everyone 6 months and older who do not have contraindications.
What’s new for 2025-2026
- FluMist (LAIV3) was approved by the FDA for self-administration (for recipients aged 18-49 years) or administration by a caregiver ≥18 years (for children and adolescents aged 2-17 years).
- FDA expanded approval of Flublok (RIV3), previously approved for persons aged ≥18 years, to children and adolescents aged 9 through 17 years. Flublok is now approved for persons aged ≥9 years
- The composition of the 2025-26 U.S. seasonal influenza trivalent vaccines includes updates to the influenza A(H3N2), A(H1N1) and B Victoria components.
- Regarding influenza vaccination of persons with egg allergy, ACIP recommends that all persons aged ≥6 months with egg allergy should receive influenza vaccine. Any influenza vaccine (egg based or nonegg based) that is otherwise appropriate for the recipient’s age and health status can be used. Egg allergy alone necessitates no additional safety measures for influenza vaccination beyond those recommended for any recipient of any vaccine, regardless of severity of previous reaction to egg. For persons who have had a severe allergic reaction (e.g., anaphylaxis) to a specific influenza vaccine, further receipt of that vaccine is contraindicated. Per package inserts, all egg-based IIV3s and LAIV3 are contraindicated for persons who have had a severe allergic reaction (e.g., anaphylaxis) to any influenza vaccine. Recommendations concerning consideration of non–egg-based influenza vaccines for such persons depends on the type of influenza vaccine associated with the previous severe allergic reaction. Providers also might consider consulting with an allergist to help identify the vaccine component responsible for the reaction. Clinical settings in which vaccines are administered should be equipped to recognize and manage acute allergic reactions. Moderate or severe acute illness with or without fever is a general precaution for vaccination. A history of Guillain-Barré syndrome within 6 weeks after receipt of a previous dose of influenza vaccine is considered a precaution for the use of all influenza vaccines. In addition to labeled contraindications for LAIV3 that are listed in the package insert, ACIP also considers several other conditions to be contraindications or precautions to the use of LAIV3. In addition, LAIV3 is not approved for and should not be given to persons aged <2 or >49 years.
- Consistent with prior guidance, everyone 6 months and older should get a flu vaccine, ideally by the end of October. However, flu vaccination is recommended as long as influenza viruses are circulating and unexpired vaccine is available. Flu vaccination is especially important for people who are at higher risk of developing serious flu complications, like those with certain chronic health conditions and people 65 years and older.
- More information about the 2025-2026 flu season is available at Key Facts about Seasonal Flu Vaccine
- For more information on this year’s flu recommendations, see: Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2025–26Influenza Season
- For detailed guidance about influenza and influenza vaccination for providers, see the CDC’s Flu Website for Healthcare Professionals
- For new and noteworthy influenza-related developments and feature stories by influenza season, visit the CDC’s Flu News and Spotlights page.
- See: CDC’s Key Facts about Seasonal Flu Vaccine
- See: Frequently Asked Influenza Questions 2025-2026 Season
- See: Influenza Antiviral Medications: Summary for Clinicians
- Also, see FluView Interactive and Respiratory Illnesses Data Channel
- There are some websites that help providers and patients locate vaccines:
- Flu and COVID-19 vaccine locations Find out where you can get a flu vaccine by asking your primary care provider, going to a local pharmacy, or visiting vaccinefinder.org for a site near you.
Influenza disease burden
CDC estimates that influenza has resulted in between 9.3 million and 41 million illnesses, between 120,000 and 710,000 hospitalizations and between 6,300 and 52,000 deaths annually between 2010 and 2024.
Preliminary in-season estimates of influenza burden in the United States for the 2024-25 season are that influenza virus infection resulted in 47-82 million symptomatic illnesses, 21-37 million medical visits, 610,000-1.3 million hospitalizations, and 27,000-130,000 deaths.
CDC posts preliminary estimates of the influenza disease burden. Every year influenza vaccines are updated to better match circulating viruses.
Your strong recommendation is important!
A health care provider’s strong recommendation is a critical factor affecting whether your patient gets influenza vaccine. Patients listen to providers when providers strongly recommend vaccination.
- There are many misconceptions about flu vaccine. CDC addresses many of these misconceptions and provides a summary of the benefits of vaccination and selected scientific studies that support these benefits.
Flu vaccine is recommended for everyone 6 months of age and older who do not have contraindications. While some flu formulations are not recommended for some patients and some patients should not receive flu vaccine at all, this is uncommon. For more guidance on contraindications and precautions for influenza vaccine, please see the CDC MMWR article detailing the 2025-26 ACIP Influenza Recommendations.
Below are the links to the latest information and data that might inform your conversations with patients in the upcoming months:
- Flu vaccine offers the best protection against flu-related illness, hospitalization, and death. Flu vaccine reduces this burden of illness.
- For the latest information about vaccine effectiveness, see CDC Seasonal Flu Vaccine Effectiveness Studies.
- Influenza vaccination was found to reduce deaths in children. A study in Pediatrics was the first of its kind to show that influenza vaccination is effective in preventing influenza-associated deaths among children. A 2022 study showed that flu vaccination reduced children’s risk of severe life-threatening influenza by 75%. And a 2020 study found that during the 2018-2019 flu season, flu vaccination reduced flu-related hospitalization by 41% and flu-related emergency department visits by half among children (aged 6 months to 17 years old).
- Influenza vaccination may make illness milder. While some people who get vaccinated may develop influenza, vaccination may make their illness milder. A 2021 published study found that in a primarily older population, influenza vaccination was associated with a 41% reduction in risk of hospitalized influenza illness. Journal of Infectious Diseases.
Influenza vaccination has been found effective in preventing influenza-associated hospitalization during pregnancy. For more information on influenza associated hospitalizations, please see the latest MMWR.
For more information on questions and answers related to this flu season, please see the General information about flu page.
Vaccine supply
DPH universally provides influenza vaccine, as well as other routinely recommended vaccines, to all children through 18 years of age. DPH only provides influenza vaccine for uninsured adults seen at public sites. For more information on state-supplied vaccine, please see the Vaccine Management page.
All flu vaccines for the 2025-2026 season will be trivalent (three-component). All will be thimerosal free vaccine (. Information about the national vaccine supply can be found at Vaccine Supply & Distribution Information for Health Care Providers | Influenza (Flu) | CDC website.
The Immunization Action Coalition (IAC) has a very helpful table of the Influenza Vaccine Products for the 2025-2026 Influenza Season.
When to vaccinate
For most persons who need only one dose of influenza vaccine for the season, vaccination should ideally be offered during September and October. However, vaccination should continue throughout the season, as long as influenza viruses are circulating. The duration of the influenza season varies from year to year, and influenza activity might not occur in certain communities until February or March. In New England, flu activity usually lasts until April and May.
To avoid missed opportunities, providers should continue to offer vaccination during routine health care visits and hospitalizations.
Safe influenza vaccine administration
CDC provides comprehensive vaccine administration resources, including Vaccine Administration eLearn at their Vaccine Administration website
Vaccine information statement
The most recent versions of Vaccine Information Statements (VISs) for Influenza Vaccines (IIV and LAIV4) for use this season are dated 1/31/2025. The latest versions of all the VISs can be found at this site.
Resources
2025-2026 Influenza Season – Fall Vaccination Clinics
Centers for Disease Control and Prevention
- Influenza Main Website
- Influenza website for Healthcare Providers: Influenza (Flu) Health Professionals
- Frequently Asked Influenza Questions 2025-2026 Season
- Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2025–26 Influenza Season | MMWR
- Resources for Mass Vaccination Clinics:
- Planning for Mass clinics
- Includes sections on:
- A checklist of Best Practices for Vaccination Clinics Held at Satellite, Temporary, or Off-site Locations, and other useful material
- Clinic Supplies Check List is a comprehensive list that can be adapted for many settings.
- Antiviral Summary for Clinicians
Immunization Action Coalition
- Model Standing Orders:
- Screening Forms:
- Flu Products Chart:
HealthMap
- VaccineFinder Find out where you can get a flu vaccine by visiting vaccines.gov/flu
American Academy of Pediatrics
Recommendations for Prevention and Control of Influenza in Children, 2025-2026 American College of Physicians
American Academy of Family Physicians
American College of Obstetricians and Gynecologists
Children’s Hospital of Philadelphia
DPH
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| Date published: | December 16, 2024 |
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