Influenza (flu) is contagious respiratory illness caused by influenza viruses. Flu can cause mild to severe illness and is more dangerous than the common cold for children. Flu symptoms usually begin suddenly, and can include fever, cough, runny nose, body aches, tiredness, vomiting and diarrhea.
Why does my child need protection against influenza?
Each year, millions of children get sick with seasonal flu; thousands of children are hospitalized and some children die from flu. During the 2024-2025 influenza season, 281 children died from the flu. Approximately half of children who died from influenza had an underlying medical condition and 9 out of 10 were not fully vaccinated.
Children commonly need medical care because of flu, especially those younger than 5 years old. Children can develop complications because of the flu, including ear infections, sinus problems or dehydration. Complications can also be severe or life threatening, such as pneumonia (infection and inflammation of the lungs), encephalopathy (brain dysfunction), myocarditis (inflammation of the heart), encephalitis (inflammation of the brain), myositis or rhabdomyolysis (inflammation of the muscle tissues) and multi-organ failure. The flu can also make chronic medical problems worse. For example, people with asthma may experience asthma attacks while they have the flu, and people with chronic heart disease may experience a worsening of this condition triggered by the flu. In some cases, flu complications can lead to death.
Which vaccines protect against influenza?
A number of seasonal flu vaccines are available each season to protect against influenza illness. They include injectable flu vaccines, or flu shots, as well as live influenza vaccine, which is given by nasal spray. Your child should receive a flu vaccine that is appropriate for their age and any underlying medical conditions they may have. Starting at 6 months of age, everyone should receive a flu vaccine each year.
Are they safe?
Flu vaccines are safe. Minor side effects can include soreness where the shot was given, headache, fever, muscle aches and fatigue. Side effects are usually mild and short-lasting, especially when compared to symptoms of the flu.
Are they effective?
Influenza viruses are constantly changing. Experts must pick which viruses to include in the vaccine many months in advance for vaccines to be produced and delivered on time. Because of these factors, there is always the possibility of an imperfect match between circulating viruses and the viruses used to produce vaccine. When the flu vaccine strains closely match the circulating viruses, vaccination can lower the chance of needing a doctor’s visit for flu by about 40-60%.
Flu vaccination has been shown to reduce the risk of flu illnesses, hospitalizations and even flu-related death. While some people who get a flu vaccine may still get sick with influenza, flu vaccination can reduce severity of illness.