The city Health Department is reporting three new cases of measles on Manhattan's Lower East Side, bringing the citywide total up to 25.
Health officials say they have confirmed 13 adults and 12 children with measles since February.
"We should be very concerned. Measles is something a pediatrician my age shouldn't be seeing at all. It used to be eradicated. Basically it's mentioned in developing countries," said Dr. Denise Infante of Gouverneur Hospital.
The outbreak started about a month ago in Upper Manhattan and the Bronx. The city health department says more than two dozen people citywide have the disease, about half of them children, half adults. Some have had to be hospitalized.
Symptoms include a rash that starts on the face and then spreads. A high fever is common along with a cough, red eyes and a runny nose lasting about five days.
The measles is very contagious and can be spread easily through the air by sneezing and coughing.
"Basically when the rash comes out you've already infected all the peopled you've come in contact in New York City," Dr. Infante said.
Doctors say the disease has resurfaced because many parents choose not to vaccinate their children.
The health department urges New Yorkers who have not been vaccinated to get their Measles, Mumps and Rubella vaccine, starting with children who are at least a year old.
Those who live and work on the Lower East hope New Yorkers take the outbreak seriously.
"It concerns me that people who have not been vaccinated have it and don't know it and think it's a slight cold," said one Lower East Side resident.
Measles can cause serious complications like pneumonia that can lead to death.
The health department says if residents are not sure their vaccinations are updated they can can get revaccinated.
In a statement, City Health Commissioner Mary Bassett said, "I urge New Yorkers to ensure all household members, including young children 12 months and older, are vaccinated. Measles is highly contagious and can spread easily through the air. If you suspect you have measles, please call your medical provider before seeking medical attention to avoid exposing others to the measles virus."
For more information, visit nyc.gov/health.