The legislation makes California the largest state to require more children who enter school, or day care, to be vaccinated against diseases including measles and whooping cough.

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SACRAMENTO, Calif. — California Gov. Jerry Brown on Tuesday signed one of the nation’s toughest mandatory childhood vaccination bills, moving to end exemptions from state immunization laws based on religious or other personal beliefs.

The legislation makes California the largest state to require more children who enter school, or day care, to be vaccinated against diseases including measles and whooping cough.

Brown, a Democrat, signed the bill after it was passed by significant margins in the state Legislature. The new law was the subject of a long and heated debate in reaction to a strong movement among some parents who refuse to vaccinate their children against infectious diseases like measles.

“The science is clear that vaccines dramatically protect children against a number of infectious and dangerous diseases,” Brown said in a statement. “While it is true that no medical intervention is without risk, the evidence shows that immunization powerfully benefits and protects the community.”

Two other states, West Virginia and Mississippi, have similar vaccination requirements.

Washington state also has seen heated debate over vaccinations. A bill failed in the Legislature this year that would have removed the state’s personal-belief exemption and made it harder for parents to choose not to vaccinate.

The state Department of Health says that nearly 83 percent of Washington kindergartners had all of the vaccines required for the 2014-2015 school year. About 4.5 percent of parents requested vaccine exemptions, including 3.4 percent who cited nonmedical reasons. That was a slight decline from the previous year.

Despite overwhelming evidence that vaccines are an essential public-health measure, the number of unvaccinated children in California has been rising, partly because personal and religious exemptions have been easy to obtain.

A measles outbreak in California this year, which began at Disneyland, ultimately infected more than 150 people and was attributed, in part, to the disease being spread by kids who had not been vaccinated.

Under the new California law, families with a nonmedical reason for declining vaccines will have to home-school their children. Unvaccinated children who are now in school will be allowed to remain.

Those with medical conditions such as allergies and immune-system deficiencies, confirmed by a physician, would be excused from immunization.