By Stephanie Stahl

PHILADELPHIA (CBS) – The measles outbreak continues to grow with more states reporting cases on the highly contagious disease. It was declared a public health crisis in one New York community, mainly among those who have not been vaccinated.

But health officials are worried that the outbreak could spread even more with traveling linked to the upcoming holidays of Passover and Easter.

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Lincoln Andrews is getting the measles, mumps, rubella vaccine. The 4-year-old is on schedule for his vaccine, but his little sister Lyla got her MMR shot a few weeks ago at 6 months old – months earlier than usual.

“Obviously I’m concerned,” Amy Andrews, their mother, said. “I have young children. I’m just glad she is at the age where she can get the vaccine.”

The Andrews family lives in New York’s Rockland County, where one of the largest measles outbreaks in the country is happening and spreading.

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Nationwide, 465 cases have been reported in 19 states this year, the second highest number since the disease was declared eliminated in 2000. The New York cases have occurred mostly among unvaccinated people in Orthodox Jewish communities.

“It’s probably one of the most contagious viruses out there,” Dr. Alanna Levine of Orangetown Pediatrics said. “If you’ve been in a room with somebody who’s had the measles, you have a 90% chance of getting the measles if you haven’t been properly immunized.”

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New York officials have declared a public health emergency in parts of Brooklyn, establishing mandatory vaccinations in an effort to stop the measles outbreak.

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“What we really need is for parents to get their kids vaccinated on time according to the recommended schedule,” Levine said, “so that we can protect patients who are too young or too sick to be vaccinated.”

Benjamin Bodenheim came to the clinic because he’s not sure if he’s fully vaccinated against the measles.

“I am going away for Passover so as a precaution I am actually just getting another shot even though I may have gotten the second shot,” he said.

Bodenheim said that he’s not taking any chance in the middle of this outbreak.

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The two doses of the MMR vaccine are 97% effective against measles.

Stephanie Stahl