MILWAUKEE - As the most severe wave of measles in 19 years spreads across the country, state representatives are trying, for the second time, to eliminate Wisconsin's "personal conviction" vaccines waiver.

Rep. Gordon Hintz, D-Oshkosh, reintroduced the bill to do so Tuesday, three years after his first attempt failed to make it out of committee.

As of yesterday, the U.S. Centers for Disease Control and Prevention reported confirmed measles cases in 22 states, the highest number since the disease was eliminated from the country in 2000.

Elimination of endemic measles does not mean the disease no longer exists, it means the disease is no longer native to the U.S. Measles cases can still exist in the U.S. due to travelers bringing it here and then spreading it to people who are not vaccinated.

Wisconsin is one of 18 states that allows parents to opt-out of the vaccines recommended for children before the start of school. Only three states — Mississippi, West Virginia and California — don't allow any nonmedical waivers, according to the National Conference of State Legislatures.

Wisconsin has a 5.3 percent exemption rate. Only four states — Arizona, Alaska, Idaho and Oregon — had higher rates of students who did not get the measles, mumps, rubella vaccine for a nonmedical reason, according to CDC data.

That increase makes public health officials worry that Wisconsin could become more vulnerable to an outbreak, should measles or another vaccine-preventable disease make its way to the state.

“We’re seeing the worst outbreak of measles in the United States in decades and, at the same time, more and more Wisconsin school kids don’t have the vaccinations currently required by state law,” said Dr. Chip Morris, president of the Wisconsin Medical Society, which supports the bill. “This is a very dangerous combination, and it’s wise that Wisconsin join with a majority of states in the nation in removing the ‘personal conviction’ exception to following the law.”

RELATED:More Wisconsin kids skip vaccines, citing 'personal conviction.' It's raising immunity concerns.

RELATED:With measles spreading, will the federal government force states to tighten their vaccination laws?

The bipartisan bill is co-authored by Rep. Tyler Vorpagel, R-Plymouth; Rep. Debra Kolste, D-Janesville; Rep. Jonathan Brostoff, D-Milwaukee; Rep. LaKeshia Myers, D-Milwaukee; Rep. Daniel Riemer, D-Milwaukee; and Senator Tim Carpenter, D-Milwaukee.

At a luncheon with members of the press in Milwaukee Tuesday, Gov. Tony Evers called the the effort to address the rising number of personal conviction waivers "critical."

"We just have to understand that there are some requirements that the state must have in order to keep everybody safe and so I would support this bill," Evers said.

Parents can refuse to vaccinate their children for religious reasons, an exemption that would still exist under Hintz's proposed law. Medical waivers would also still exist.

Medical reasons to not get a vaccine could include people who have had cancer treatments or otherwise have a compromised immune system or an allergy to vaccine ingredients.

Personal conviction waivers are the vast majority of nonmedical vaccine waivers used in Wisconsin and the Wisconsin Department of Health Services has seen an uptick in the percentage of families that take the waiver in the past two decades.

Hintz's bill is backed by 11 health care and advocacy groups, including the Medical College of Wisconsin, the Wisconsin Public Health Association, the Wisconsin Nurses Association and the Wisconsin chapter of the League of Women Voters.

"Vaccination is not just about protecting individuals, it is about protecting everyone," Hintz said in a statement. "People who choose to opt out of vaccinations are only protected by those who are vaccinated and reduced their risk of exposure. Our numbers are heading in the wrong direction, and it is time to act and close the personal waiver loophole."

An earlier version of this story incorrectly identified Rep. Jonathan Brostoff as a Republican. The Milwaukee legislator is a Democrat.

Contact Devi Shastri at 414-224-2193 or DAShastri@gannett.com. Follow her on Twitter at @DeviShastri.