The number of confirmed measles cases in New York City has increased to 329 since October, and according to the city’s health department, the outbreak is expected to worsen over the next 3 to 5 weeks.

“We expect these numbers to continue, given the incubation period,” NYC Health Commissioner Dr. Oxiris Barbot said Monday. It can take up to 21 days for measles symptoms to appear after a person is exposed to the virus.

“We are very concerned about Passover and the [spring] break, this is a time students and families are congregating,” Deputy Mayor of Health and Human Services Dr. Herminia Palacio said. “This is a highly contagious disease. 90 percent of people who are unvaccinated, or non-immune, and come in contact with someone with measles will become infected.”

The New York City measles outbreak is the largest in the country. According to the Centers for Disease Control and Prevention, the U.S. has been experiencing its second-worst measles outbreak since the highly contagious and dangerous disease was declared eliminated in 2000. So far in 2019, there have been 555 measles cases across 20 states.

There have been 44 new New York measles cases since last week, when the health commissioner issued a rare emergency order mandating vaccines for everyone living in the outbreak areas in Williamsburg, Brooklyn.

The measles outbreak has spread primarily in the Orthodox Jewish community throughout four zip codes encompassing greater Williamsburg.

The New York Health Department also announced Monday it shut down the United Talmudical Academy child care center for 3-5-year-olds in Williamsburg for refusing to -- or being unable to -- disclose vaccination and attendance records for students attending its center, a violation of the health commissioner’s emergency order issued last week.

“The school will be allowed to reopen once they convince us that they are able to, on a consistent basis, keep students in school that should be in school, and keep students out of school that should not be in school,” Barbot said.

HEALTH OFFICIALS WARN AGAINST 'MEASLES PARTIES' AMID OUTBREAK

Last week, the commissioner ordered all yeshivas, Jewish religious schools and child-care centers in the outbreak zone to exclude any unvaccinated children from coming to school. An additional 22 other yeshivas, Jewish religious schools and child-care centers have been given violation notices and face being shut down if they don’t comply.

Barbot also confirmed Monday that the city issued fines to people or schools who chose not to follow the mandatory vaccination order. The city said those individuals who become infected with measles and chose not to get vaccinated since the mandatory order would be fined $1,000 dollars.

When pressed as to how many fines were issued, Barbot said she did not know at the time.

Of the 329 confirmed New York measles cases, 284 are children and 45 are adults. There have been 25 hospitalizations and of the six people who have been taken to the intensive care unit, two remained and were in stable condition.

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New York health officials said they were working with Orthodox Jewish leaders to combat anti-vaccination campaigns. Dr. Barbot said they have issued robocalls throughout 30,000 households and mailings detailing all the ways that vaccines are safe.

“Vaccine is the path to stopping this outbreak,” Palacio said. “This anti-vax movement has proven to be very dangerous. These outbreaks should not be happening. We should not have active measles in the United States. Period. Full stop.”