Cases of measles continue to spread, as an outbreak centered in upper Manhattan and The Bronx has now infected a total of 19 people, including nine children. Three new cases have been reported today, including some Brooklyn residents, but a Health Department spokesperson tells us they were infected in Manhattan, not Brooklyn.

NBC is reporting that officials have yet to locate the source of the outbreak, which first appeared in February. They are urging everyone in New York City who has not been vaccinated to get vaccinated. Three of the children infected were too young to have received the vaccination, while two others were not vaccinated by parental decision.

Last week, two people were infected when they were exposed to another infected individual in a hospital waiting room. "One can understand how that happened, but that's exactly why we're trying to minimize the opportunity for future exposure," Dr. Jane Zucker of the New York City Health Department told ABC News.

To that end, doctors are urging individuals who believe they are infected to call their doctor ahead of time before coming to the hospital, to avoid possibly infecting others. Doctors are also urging individuals who believe they have been vaccinated to track down documentation of their vaccination. Several infected adults believed they had been vaccinated in the past, but were unable to confirm it. A vaccination, doctors continue to reiterate, is quick and safe.

Complications from measles can include "pneumonia, miscarriage, brain inflammation, hospitalization and even death."