The Health Department is investigating a chicken pox outbreak in a predominantly-Hasidic section of Williamsburg having documented 75 cases of the highly contagious disease since March, according to the city. A spokesperson for the department confirmed that an alert went out to local healthcare providers on Monday. If you haven't vaccinated your toddler yet, the city is advising you to get to it.

All of the cases have been children aged 10 or younger, the majority of them three years old. Of the 75 cases, 72% were among kids who had not received a vaccination. Another 14% of the patients had not been administered the recommended number of vaccine doses.

According to the Health Department, two doses of the chicken pox vaccine is 98% effective. The first dose is recommended at 12 months, followed by a second dose at age four.

In 2014, the DOH told Forward that 96% of students at yeshivas in Brooklyn were vaccinated—a statistic backed up by the outlet's sources in the community. Still, there's a documented anti-vax trend among Ultra-Orthodox jews. An anti-vaccine magazine called P.E.A.C.H. launched in 2014, and was reportedly distributed in Orthodox neighborhoods in Brooklyn.

Chicken pox is contagious between people who haven't been vaccinated—so much so that before the vaccine was established, most people could expect to catch it. The disease spreads through physical contact, coughing and sneezing, according to the Mayo clinic. Alarmingly, infected individuals are contagious two days before that telltale rash (click at your own risk) crops up. Once the rash is in full swing, you're contagious until you scab over (usually after about five days). Here's a lovely summary of the symptoms from Outbreak News Today:

The disease is characterized by fever and a red, itchy skin rash of that usually starts on the abdomen, back or face and then spreads to nearly all parts of the body. The rash begins as small red bumps that appear as pimples or insect bites. They then develop into thin-walled blisters that are filled with clear fluid which collapse on puncture. The blister then breaks, crusts over, and leaves dry brown scabs.

"We are working closely with the affected community, including meeting with community leadership and notifying elected officials," said a spokesperson for the Health Department in a statement. "Vaccines continue to be the safest way to protect a child against many different childhood diseases, including chicken pox, measles, and whooping cough."

It's worth noting that pregnant women who didn't have childhood chicken pox and haven't received a vaccination are more susceptible than other adults. In other words, just one more thing to worry about.