As a result of more parents forgoing vaccines for their children, the highly contagious measles virus made a comeback in 2018, with 200 confirmed cases around the country.

Experts say that pervasive internet misinformation around vaccine safety has led to "hot pockets" of areas where kids are growing up unvaccinated.

Healthcare, including big public health issues, will be at the forefront of the 2020 election.

In 2016, President Donald Trump falsely claimed that vaccines are linked to autism on multiple occasions.

Here's what all the 2020 presidential candidates have said about vaccines.

The measles vaccine was introduced in the 1960s and US government declared measles eradicated in 2000. But the highly contagious disease made a comeback in the winter of 2018, with nearly 200 confirmed cases reported across the country.

The state of Washington declared a state of emergency earlier this year after 65 people in the state contracted the disease — with 47 of them young children under the age of 10 who had not been vaccinated.

Despite the broad scientific consensus that vaccines are safe and effective, as well as the dozens of studies discrediting any link between vaccines and autism, misinformation about vaccine safety abounds on the internet — and experts say it's leading to an increase in kids in places like Washington going without their shots.

Read more: From autism risks to mercury poisoning, here are 10 lies anti-vaxxers are spreading about the measles vaccine in the Pacific Northwest

An exhaustive new study of 650,000 Danish children again thoroughly disproved the validity of the connections between the measles vaccines and autism, but scientists worry that the anti-vax movement growing stronger over time means "we now live in a 'fact-resistant' world where data have limited persuasive value."

On March 4, Ohio teenager Ethan Lindenberger, who began getting vaccines against his mother's wishes after he turned 18, appeared before the Senate Committee on Health, Education, Labor, and Pensions to testify to the importance of vaccination and the impact the pervasive misinformation on Facebook had on his mother.

“I feel like if my mom didn’t interact with that information, and she wasn’t swayed by those arguments and stories, it could’ve potentially changed everything,” he told the Washington Post. “My entire family could’ve been vaccinated.”

Healthcare, including big public health issues, will be at the forefront of the 2020 election.

In 2016, President Donald Trump falsely claimed that vaccines are linked to autism on multiple occasions.

Here's where all the 2020 presidential candidates stand on vaccines with the exception of Sen. Cory Booker and Julian Castro, who have not made recent public statements on the issue and did not return INSIDER's requests for comment.