BOISE, Idaho (AP) — Senators approved a measure they hope will improve Idaho's childhood immunization rates that rank among the nation's lowest by changing a reminder system for parents.

The measure passed 31-3 and now heads to the House.

If this becomes law, parents would have to "opt out" of getting an reminder from their doctor that a shot is due, rather than the current requirement to "opt in."

According to the National Immunization Survey, Idaho's immunization rate for children ages 19 to 35 months is 66 percent; the national average is 77 percent.

Sen. John McGee, a Republican from Caldwell, says "Those immunization rates are embarrassing."

Foes of the bill raised concerns about privacy, pressure and meddling of big business in a personal issue for many the state's residents.