Research has shown that children less than 5 years of age are at high risk of serious flu-related complications. It is estimated that more than 20,000 children less than 5 years old are hospitalized due to flu each year in the U.S. Many more have to go to a doctor, an urgent care center, or the emergency room because of flu. Complications from the flu can include pneumonia, dehydration, worsening of long-term medical problems like heart disease or asthma, encephalopathy, and sinus problems and ear infections. In rare cases, complications from the flu can lead to death. Because children are at increased risk of getting severe illness from flu, CDC recommends that all children 6 months up to their 5th birthday get a flu vaccine every fall or winter. This fact sheets presents advice on protection against the flu for caregivers of children less than 6 months.