WASHINGTON — The Trump administration, which in recent months had avoided public discussions of vaccine policy because of concern around the political repercussions, is changing course.

Speaking from the Oval Office, President Trump on Monday unveiled a new executive order as he and his top health officials presented a new, skeptical government approach to vaccines, making extraordinary claims without evidence to support the remade federal agenda.

“That’s a big one in my book,” Trump said after signing the order.

The executive order lists vaccines to be recommended for all children, those at high risk of infection, or just in consultation with a clinician — a stark change from the usually public, scientist-led process of determining the federal government’s approach to immunization issues. The new “Gold Standard Childhood Vaccine Recommendations” were instead made in consultation with the president’s advisers and relied on comparing the U.S. system to those in other countries. (The White House did not immediately answer questions about why that approach was taken and who advised the president on the order.)

The order recommends all children get 11 vaccines instead of the 18 previously recommended by the federal government — and would spread out the doses over more time, the president said. The administration did not provide immunological evidence for the changed schedule.