PHILADELPHIA (CBS) – Measles cases are approaching numbers the United States hasn’t seen in 20 years. The number of measles cases in the United States is approaching the record, with 70 new cases reported, for the decade in a four-month time span, according to new data released Monday.

Pediatrician Dr. Jeffery Avner is on the front lines of a measles outbreak that is showing no signs of slowing down.

“When you see a disease that is preventable with a vaccination, it is somewhat disheartening,” said Avner, the Chair of Pediatrics at Maimonides Children’s Hospital of Brooklyn.

His hospital in Brooklyn has treated nine cases of measles so far, including an adult and a child who ended up in the intensive care unit.

‘Parents don’t really understand risks of measles because it’s become such a rare disease, but measles does have very serious complications. One in 20 children with measles get pneumonia, which by the way, is the most common cause of death,” Avner said.

Concern Growing Over Measles Possibly Spreading With Spring Break Travels, Religious Holidays This Weekend

The Centers for Disease Control and Prevention is now reporting 626 cases of the highly contagious virus in 22 states, including New Jersey and Delaware.

It’s the second-highest number of cases reported since measles was declared eliminated in 2000.

Most of the New York cases have occurred in unvaccinated people in Orthodox Jewish communities.

Doctors across the country are also fighting against the anti-vaccine movement among some parents.

“They are getting information from sources that are incorrect, that are trying to sell them on ideas and studies that were fraudulent and debunked,” Avner explained.

Avner says if people stay unvaccinated, the measles could continue to spread.

Some experts are concerned with Passover this week there will be an increase in measles cases after the holiday in the coming weeks.