The New York City Health Department says it's investigating a measles outbreak in northern Manhattan and the Bronx.
The department said Friday it has identified 16 cases — seven of them adults. Four of the patients have required hospitalization.
The Health Department says it's working with hospitals to prevent exposure to the virus in emergency departments.
It's urging all New Yorkers to make sure they're vaccinated against measles.
Adults who don't know their vaccination history can be revaccinated or get a blood test to see if they are immune.