Hundreds of anti-vaccination supporters demonstrated outside a public hearing in Washington state on Friday to protest a bill that would make it harder for families to opt out of mandatory vaccinations for children, the Associated Press reported.

The protest took place amid the state's worse measles outbreak in more than two decades. Health officials have reported at least 56 cases in Washington and Oregon.

An estimated 700 people demonstrated in Olympia, Washington, most of whom opposed stricter requirements, The Washington Post reported. ADVERTISEMENT

The modern anti-vaccination movement has picked up recently, despite research finding that the vaccine for measles, mumps and rubella (MMR) is not linked to autism.

“I want to remind you that the MMR vaccine is extremely safe and highly effective,” Washington state health secretary John Wiesman told lawmakers, according to the Times, adding that “all reputable scientific studies have found no relation between measles and autism.”

Wiesman called on lawmakers to remove exemptions for personal and philosophical reasons, citing the current outbreak. The bill, introduced by state Rep. Paul Harris (R) currently includes medical and religious exemptions, though Harris said he plans to amend the bill to remove those exemptions.

“You cannot find a peanut in one of my schools [because of concerns about allergies], but unvaccinated kids are walking around in my schools because of a personal exemption?” Harris said, according to The Post. "I find it appalling.”

The Pacific Northwest hosts some of the nation's most vocal anti-vaccination activists. Washington, Oregon and Idaho have some of the lowest MMR vaccination rates in the U.S., according to the Center for Disease Control.