By Pat Loeb

PHILADELPHIA (CBS) — Pennsylvania students need more vaccine doses before they can start school, under new rules adopted by the state Health Department. Philadelphia officials are urging parents to get the shots now.

Skeptics notwithstanding, Health Commissioner Tom Farley is a vaccine advocate.

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“Vaccines are really the greatest advance in medicine,” he said.

So he supports the changes and is helping make sure every Philadelphia student complies.

“If you don’t do that, your child may not be able to start school on time and more importantly, your child may not be protected against these serious diseases,” he said.

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The new rules call for a fourth dose of the polio vaccine, after turning four-year-old, for all students. And 12th graders must receive a second shot for meningitis.

The grace period for attending school without required vaccines has been shortened to five days, which superintendent William Hite says the district must enforce, though he notes there is a little leeway.

“If they get a note from their physician that they are scheduling that vaccination then we can allow children in school,” he said.

School starts September 5th.

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Hite and Farley urge parents to call pediatricians now to get up to date and, if they don’t have a doctor, to call city district health centers at 215-685-2933.