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“The Vaccine Safety Handbook” appears innocuous, a slick magazine for parents who want to raise healthy children. But tucked inside its 40 pages are false warnings that vaccines cause autism and contain cells from aborted human fetuses.

“It is our belief that there is no greater threat to public health than vaccines,” the publication concludes, contradicting the scientific consensus that vaccines are generally safe and highly effective.

The handbook, created by a group called Parents Educating and Advocating for Children’s Health, or Peach, is targeted at ultra-Orthodox Jews, whose expanding and insular communities are at the epicenter of one of the largest measles outbreaks in the United States in decades.

On Tuesday, Mayor Bill de Blasio declared a public health emergency in parts of Brooklyn in an effort to contain the spread of measles in ultra-Orthodox neighborhoods there. He said unvaccinated individuals would be required to receive the measles vaccine — or be subjected to a fine — as the city escalated its campaign to stem the outbreak.