Health officials are urging Brooklyn residents to protect themselves as they head to Passover and Easter celebrations amid a measles outbreak mainly affecting the Orthodox Jewish community.

The health commissioner has confirmed that nearly 300 measles cases have popped up in New York City. The Centers for Disease Control and Prevention is urging anyone traveling to make sure their immunizations are up to date, especially those traveling abroad.

The CDC says it is common to get measles in other countries and bring it back to the United States.

MORE: NYC orders mandatory vaccines for some amid measles outbreak

City officials say this has been the largest outbreak New York City has seen since 1991. While many are hoping to enjoy their holidays away from home, officials met Tuesday to spread the word that measles is a dangerous and potentially deadly disease.

Mayor Bill de Blasio says that unvaccinated people living in select ZIP codes will be required to get the MMR vaccine or potentially be fined $1,000. New Yorkers can call 311 for a list of facilities that provide the vaccination.