Rockland County in New York state has declared a state of emergency following a severe outbreak of measles and has banned unvaccinated children from public spaces.
Tuesday's announcement followed other outbreaks of the disease in Washington, California, Texas and Illinois.
Rockland County, on the Hudson River north of New York City, has barred unvaccinated children from public spaces after 153 cases were confirmed, CNN reported.
Violating the order would be punishable by a fine of $500 and up to six months in prison.
Vaccination rates have dropped steadily in the US with many parents objecting for philosophical or religious reasons, or because they believe misleading information that vaccines cause autism in children, the BBC reported.
"We will not sit idly by while children in our community are at risk," Rockland County Executive Ed Day said in a statement. "This is a public health crisis and it is time to sound the alarm."
The outbreak in Rockland County was largely concentrated in the ultra-Orthodox Jewish community, the New York Times reported.
It is believed it could have spread from other predominantly ultra-Orthodox areas around New York which have already seen outbreaks of measles.
Measles is a highly infectious disease and can cause serious health complications, including damage to the lungs and brain.
The World Health Organization has declared the anti-vaccine movement to be one of the top global health threats for 2019.