Six years ago, two communities in New York – one in Brooklyn and one in Rockland County – were facing the worst measles outbreaks the United States had seen in decades. It was the closest the nation has gotten to losing elimination status for the extremely contagious disease,

A resurgence of measles is sweeping through communities nationwide. Health officials warn that the highly contagious virus, which had been nearly eradicated in many regions, is making a dangerous comeback,

The CDC is urging travelers to ensure they are vaccinated against measles as the outbreak spreads ahead of the spring and summer travel season.