There's an urgent warning about measles cases in New York and what it means for your spring break plans.

At least three cases have been confirmed in New York City and one in Suffolk County.

So far, none have been detected in Westchester County.

However, Dr. Marina Keller, MD, infectious disease expert, with Westchester Medical Center, says this needs to be taken seriously.

"The big problem with measles is it's the most contagious infection we have known to mankind, it's very easy to catch it if you're not vaccinated," Dr. Keller explains.

That's why Dr. Keller says getting vaccinated right now is so crucial.

Many schools in the Hudson Valley are just a couple weeks out from spring break.

"It's really important to get vaccinated this week to have full protection by the time you start traveling," says Dr. Keller.

Doctors tell News 12 the vaccine is safe, effective and the biggest way to stop these cases from spreading even further.

You can keep track of the latest on the measles cases through the New York State Department of Health HERE.