Health officials in Rockland County, New York, are taking additional steps to contain a current measles outbreak there.
The county announced Tuesday that it's forcing anyone with measles to stay home for up to 21 days in order to help stop the spread of the virus, which started back in October. It'll also now require that minors have proof of vaccination, immunity or an exemption form on file in order to attend schools and childcare facilities.
"I have the authority from the state Commissioner of Health to exclude those children who are not up to date on their immunizations," said Patricia Ruppert, Rockland County Commissioner of Health. "Newborns, pregnant individuals, and those with weakened immune systems can't get vaccinated, so it's important that everyone around them become vaccinated to protect them."
Health regulators are also linking the New York outbreak to measles cases in Michigan. And New York City's mayor recently declared a public health emergency, requiring vaccinations for people living in specific zip codes.
Those aren't the only parts of the U.S. that are dealing with the illness. According to the CDC's latest data, there've been more than 555 confirmed measles cases so far in 20 states this year.
The agency attributes recent outbreaks to travelers who've brought the virus into the U.S. from other countries, like Israel and Ukraine.
Measles is a respiratory illness that's highly contagious — and also vaccine-preventable. Health regulators recommend children be fully immunized against 14 preventable diseases by the time they're 6 years old. That includes the measles, mumps and rubella, or MMR vaccine.
Additional reporting from Newsy affiliate CNN.