When questioned whether an order to vaccine people was legal, Mayor Bill de Blasio said yes, noting his office is "absolutely certain we have the power to do this". "So we are taking urgent steps right now to make sure we can stop this". "We have a situation now where children are in danger. We unfortunately still witnessed a drop in the vaccination rate due to vaccine hesitancy", the DOH added.
Many vaccine opponents believe medically baseless claims that inoculations can cause autism and other negative health effects. The MMR vaccine is demonstrably safe, she said, and since the 1960s has turned a fatal disease into a preventable one.
And "because measles is so transmissible, in order to prevent this kind of spread, you have to have very high levels of vaccine [coverage] - well over 90%", said Dr. William Schaffner, an infectious disease and preventive medicine specialist at Vanderbilt University Medical Center in Nashville, Tennessee.
By far most of the city's cases are kids under 18 years age. But over time, public health officials focused more on requiring children to be vaccinated to attend school. While no one has died, a handful have been admitted to intensive care.
"People are spreading different viewpoints, but some of them are clearly false and not backed up by science", said de Blasio. All people living within five listed zip codes are required to have the measles vaccine, or otherwise be fined.
The city also warned that yeshiva religious schools and day care programs serving the local Orthodox Jewish community would face penalties and possible closure if they continue to take in unvaccinated students.
Health officials are also urging people to vaccinate their children if they plan on traveling to upstate New York, Israel, Europe or other parts of the US where outbreaks are occurring. A judge halted that ban last week. He referred to the large number of cases as "measles-crisis", against the mandatory vaccination, but will help. The CDC reports measles is still common in many parts of the world, including some countries in Europe, Asia, the Pacific and Africa.
"This is the epicenter of a measles outbreak that is very, very troubling and must be dealt with immediately", he said at a news conference in Williamsburg.
The city's health commissioner, Dr Oxiris Barbot, said that the majority of religious leaders in Brooklyn's large Orthodox communities support vaccination efforts, but that rates have remained low in some areas because of resistance from some groups that believe the inoculations are risky. Two people contracted measles while in the United Kingdom and one in Ukraine.
The highest figure - 667 - occurred in 2014.