It's the first reported pediatric death in Florida for the 2018-19 flu season.
Vaccinations have been shown to reduce a child's likelihood of dying from the flu by 60 percent, health department officials said.
Vaccines are recommended for anyone at least six months old.
The unidentified child was otherwise healthy before getting the flu, according to the Florida Department of Health's Bureau of Epidemiology. The child tested positive for influenza B at a local health care provider.
About 80,000 Americans, including 180 children, died last year in the deadliest flu season in more than 40 years, according to the Centers for Disease Control and Prevention.
Approximately 80 percent of those who died were not vaccinated.