NEW YORK — It may be a bad flu season for kids, but early signs suggest the flu vaccine is working OK.

For kids, the flu vaccine has been more than 50% effective in preventing flu illness severe enough to send someone to the doctor's office. Experts say that's considered pretty good for a flu vaccine. The U.S. Centers for Disease Control and Prevention released the estimates Thursday.

The vaccines are made each year to protect against three or four different kinds of flu virus. The ingredients are based on predictions of what strains will make people sick the following winter.