"Too few young children are protected against influenza, which for this age group, can be a very serious illness,” said Dr. Julie Gerberding, CDC director. “This season, CDC not only encourages flu shots for young children -- we recommend them. We’re urging more parents to get their children vaccinated against influenza, because annual flu shots will reduce cases of influenza and its complications, decrease hospitalizations, and save lives."

Children who have not previously been vaccinated require two doses for full protection. Those who have received any dose of influenza vaccine in previous years need just one annual dose.

Children less than two years old -- even those in good health -- are more likely than older children to be hospitalized with serious complications if they get the flu, recent studies show.

Because children younger than two are at increased risk for influenza-related hospitalization, vaccination is also recommended for their family members, other people living or working in their household and childcare providers.

It is particularly important that people who are contacts of children younger than six months be vaccinated, because there is no approved vaccine for children younger than six months of age.

During the 2003-2004 influenza season, CDC received reports of 152 flu-related deaths among children under age 18 from 40 states. The vast majority were not adequately vaccinated. Almost half of the children had an underlying medical condition, but 40% were previously healthy.