New rules requiring young children in day care or preschool programs to be immunized against the flu were approved today by New Jersey Health Commissioner Fred M. Jacobs.

The action confirmed a state Public Health Council vote on Monday to amend immunization regulations to include the flu shot as well as pneumococcal vaccine, effective next September.

The new mandate was opposed by some parents, who testified and wrote letters expressing concerns about the safety of vaccines. Some people believe that thimerosal - a mercury-containing preservative that was once used in vaccines and can still be found in trace amounts in some of them - can trigger autism.

But researchers say they have found no clear evidence of a link. The new requirements match the recommendations of the American Academy of Pediatrics and the U.S. Centers for Disease Control and Prevention.

Pennsylvania already requires children in daycare centers and preschool to be immunized according to the schedule recommended by CDC's Advisory Committee on Immunization Practices, the Academy of Pediatrics and the American Academy of Family Physicians.

The requirement includes annual flu shots starting at six months of age.