[What you need to know to start the day: Get New York Today in your inbox.]

CHESTNUT RIDGE, N.Y. — The mother of an unvaccinated child here in the New York suburbs says eating papaya helps to combat measles. The father of another child who has not been immunized believes that big pharmaceutical companies are paying millions of dollars to doctors, government officials and even judges to bury the truth about vaccine complications.

Another mother says the souls of her children are on a journey that vaccines would impede. “As a parent, for me, a lot of my job is to just not put extra obstacles in that soul’s way,” she said.

All three parents represent an anti-vaccine fervor on the left that is increasingly worrying health authorities. They often cluster around progressive private schools that are part of the Waldorf educational movement, and at the Waldorf school here, 60 percent of the school’s 300 or so students were not vaccinated against measles and other highly contagious diseases as of late last year.

The measles epidemic in the New York region has largely spread among ultra-Orthodox Jewish communities in Rockland County and in New York City. But health authorities fear it could jump to other unvaccinated groups like the ones linked to the children of families who attend Waldorf schools.