A group of parents in Brooklyn are seeking an injunction to prevent measles vaccines from taking effect.
The lawsuit filed by parents against the Department of Health of New York City called the Emergency Ordinance "arbitrary and capricious" and the measures that "drastically" require it.
The order issued by the mayor of New York City, Bill de Blasio, last week requires that all persons aged 6 months and over live, work, or school within the specified Williamsburg, Brooklyn, or postcode visit, be vaccinated.
The defendants argued that "there is insufficient evidence of a measles epidemic or a dangerous outbreak to justify forced vaccination," and they accuse the city of having taken the least restrictive measures to stop the outbreak.
The lawsuit was filed by five mothers on behalf of themselves and their minor children. They are listed as being in Williamsburg and Clinton Hill, parts of Brooklyn included in the mandatory vaccinations.
De Blasio described the measles as "a very serious situation" and referred to the "danger of this disease and how contagious it is".
The affected postcodes are heavily populated with Orthodox Jews, and the mayor was looking for a vaccine before people travel to the Passover, which starts on Friday.
"To make sure it's a great holiday, we need to make sure people are protected," said de Blasio.
According to the Centers for Disease Control and Prevention, there were 285 confirmed cases of measles in Brooklyn and Queens from October 2018 to April 8, 2019.
The CDC states that most confirmed cases were members of the Orthodox Jewish community, and the first case was from an unvaccinated child who had become infected on a trip to Israel.
New York is one of 20 states in which measles cases were confirmed in 2019. Between 1 January 2019 and 11 April, there were 555 confirmed cases of measles in the US.