Under House Bill 3063 in Oregon, children would have to receive vaccinations in order to attend school, unless they have a doctor's note seeking an exemption for medical reasons.

SALEM, Ore. — Hundreds of people rallied outside the Capitol in Salem Thursday to voice their opposition to legislation that would crack down on vaccine exemptions.

Under House Bill 3063 in Oregon, children would have to receive vaccinations in order to attend school, unless they have a doctor's note seeking an exemption for medical reasons. Parents would no longer be able to claim vaccine exemptions for religious, personal or philosophical reasons.

The bill was introduced following a measles outbreak in nearby Clark County, Wash., where 70 people have been diagnosed with measles. The outbreak led to a handful of Oregonians getting the virus, health officials said.

The Washington State House of Representatives has passed similar legislation to the one being considered by the Oregon Legislature.

The group hosting Thursday’s rally, Oregonians for Medical Freedom, argued vaccine injury and adverse reactions to vaccines affects thousands of families in Oregon. The group encouraged people who they said were victims of vaccine injury to share their stories with legislators.

Opponents said the legislation would deny more than 31,500 kids their right to a public education if they miss a vaccine shot. They also argued a child’s medical treatment should be left to the parents, not the government.

Health officials in Oregon and Washington have advised people to make sure they are up to date on their vaccinations.

Wednesday, U.S. Surgeon General Vice Admiral Jerome Adams was in Vancouver to emphasize the importance of education about vaccinations. Adams said he thinks it should be easier to get a vaccination than an exemption.

"We need to make sure we are helping folks understand what the science tells us," he said. "States that have more opportunities to opt out of vaccinations have lower vaccination rates and a higher risk for vaccine-preventable disease outbreaks."