Influenza

Flu season information

Influenza (flu) is a respiratory infection caused by a variety of flu viruses spread primarily by droplets made when infected people cough, sneeze, or talk. Less often, a person might become infected with flu by touching a surface or object contaminated with flu virus and then touching their own mouth, eyes, or nose. influenza-like-illness (ILI) is defined as the presence of fever and cough or fever and sore throat without a laboratory-confirmed etiology.

Season
The flu reporting year uses standard reporting weeks outlined by the Centers for Disease Control and Prevention (CDC), where every year has 52 or 53 reporting weeks. Though flu season ends May 17, 2025 (week 20), surveillance continues year round. Seasons vary in timing, severity, and duration. It is not possible to predict what each flu season will be like in Florida.

Surveillance and investigation
Surveillance is conducted to detect changes in the flu virus to help determine the annual northern hemisphere vaccine composition and to prepare for potential pandemics. Surveillance is also conducted to identify any unusually severe presentations of flu, detect outbreaks and determine the onset, peak, and wane of the flu season to assist with prevention, particularly in high-risk populations like the very young, adults aged ≥65 years, and pregnant women.

Individual cases are not reportable in Florida with the exception of novel flu A (a new subtype of flu A) and fluassociated pediatric deaths. All outbreaks are reportable in Florida.

The Florida Department of Health will continue to make updates on the trends presented in this report as needed.

Annual vaccination is the best way to protect yourself and others from potentially severe complications from flu. Flu shots take up to two weeks to become fully effective, so it’s important to get vaccinated as soon as possible to reduce your chances of getting the flu this season. To locate a vaccine near you, visit Vaccines.gov.

CDC recommends antiviral treatment be initiated as soon as possible for people with confirmed or suspected flu who are at higher risk for complications ( children <2 years, adults ≥ 65 years, pregnant people, and people with underlying medical conditions). Treatment should be administered within 48 hours of illness onset. For more information, contact your health care provider.