President Donald Trump signed an executive order on Monday aimed at reshaping the federal government’s approach toward childhood vaccines, insisting that infants should receive fewer immunizations over a longer period despite little scientific evidence supporting such sweeping changes.

"Parents, children will suffer:" Former CDC chief on Trump's order on childhood vaccines

The order will recommend administering each vaccine in its own visit and separating the measles, mumps and rubella (MMR) vaccine into three different shots and direct the nation’s health department to...