In declaring a public health emergency, Commissioner of Health Dr. Oxiris Barbot said the number of cases diagnosed within certain zip codes of Williamsburg "continues to grow as new cases are still occurring" and that he deemed this to be an "existing threat to public health in the City of NY".
The mayor said that the situation in the ultra-Orthodox Jewish community is a measles crisis, and the Associated Press reports officials are blaming anti-vaxxers for spreading misinformation. All residents in the affected areas have been told to get vaccinated or face a fine.
The city can't physically force someone to get a vaccination, but officials said people who ignore the order could be fined US$1000 ($1325).
Tuesday's announcement was the first time NY has ordered mandatory vaccinations in recent history, according to health officials.
According to the New York Times, there have been 285 confirmed cases of the highly infectious disease in the last several months, mostly affecting members of Brooklyn's Orthodox Jewish communities. Most of the children were unvaccinated or partially vaccinated.
The vast majority of cases are children under 18 years of age (246 cases), and 39 cases are adults.
Health officials may forcibly inject residents of Williamsburg, Brooklyn who flout a mandatory vaccination order, a City Hall spokeswoman confirmed Tuesday.
Barbot cited a group of "anti-vaxxers" who are seeking to undermine the public health emergency. "They have been spreading risky misinformation based on fake science", Barbot said.
What's more, the more children in the community have it, the higher risk of exposure for kids with weakened immune systems and pregnant women, who need to avoid the virus.
The outbreak has been predominately among ultra Orthodox Jews, and not unsimilar to outbreaks among other insular communities in recent years where parental fears about immunization have been influenced by an anti-vaccine movement in the larger population that persists despite scientific studies showing the safety of the measles, mumps and rubella vaccine. This vaccine is safe.
"The City has worked aggressively to end this outbreak, and today's declaration of a public health emergency and new vaccine mandate, in combination with the blanket Commissioner's Orders for yeshivas, ensures we are using every tool to protect New Yorkers".
The Brooklyn outbreak has been traced to an unvaccinated child who became infected on a visit to Israel, which is also grappling with an outbreak, according to New York City's Department of Health.
Measles "parties" stems from the once-popular trend of "pox parties" - intentionally exposing children to chickenpox, before the Varicella vaccine was rolled out in 1995.
Measles can be prevented through vaccinations.
"I understand that parents may be afraid of getting their children vaccinated", health commissioner Barbot said.
It said the vaccine was 97 per cent effective.