ROME — Italian parents will no longer have to provide state-run schools with a doctor’s note to show that their children have been vaccinated, the country’s new populist government announced on Thursday — a move that raised alarm among experts who fear that compliance with vaccines will drop.

The new rule, announced at a news conference by Giulia Grillo, Italy’s health minister and a prominent member of the anti-establishment Five Star Movement, requires only the assurance of parents that their children are immunized to enroll in school this September.

The government said its aim was to simplify enrollment procedures and enable school participation for all, including children whose parents do not have their paperwork in order yet.

“We want to spur school inclusion and simplify rules for parents,” Ms. Grillo said.

But critics of the move say the Italian government is eroding faith in science and public norms.