The latest results on the swine flu vaccine show the younger set will probably need two shots to protect against the disease.
Children from six months to nine years old were found to need a double dose of the vaccine, but children age 10 and older will be protected with one shot.
Doctors say the younger kids don't have the proper immunity built up to help fight off the disease.
Just a few weeks ago, experts announced that one swine flu vaccine would be enough for adults.