OKLAHOMA CITY, Oklahoma - For a third year in a row, State Senator Ervin Yen has introduced legislation making mandatory for just about every Oklahoma school student to be vaccinated.

The Oklahoma City Anesthesiologist wants to eliminate a parent’s ability to check a box and keep their school-attending child from being vaccinated. Under Yen’s plan, only children with a medical condition would be exempt for being vaccinated.

Yen puts Oklahoma vaccination rate at 90-percent; too low, according to the lawmaker.

“I’m worried about those kids who are immune compromised, who cannot be vaccinated, I don't want them going to school and being exposed,” said Yen.

For two years, Yen has unsuccessfully pushed for vaccination legislation.

Groups like Oklahomans for Vaccine and Health Choice have lobbied against the lawmaker’s efforts. His original bill in 2015 wasn't even put up for a vote in the Senate's Health and Human Service Committee. Critics said the mandatory vaccination was too far reaching.

But this time around Yen is the chair of the same committee. He says Senate Bill 83 will be heard. He claims the fact that there were over 300 cases of the mumps in Oklahoma this past year could impact lawmakers this legislative session.

“I’d like to get it passed right away before we have a huge outbreak and a lot of people die,” said Yen.