Officials continue working to control the measles outbreak that has hit 20 states and infected nearly 600 people.
It's one of the reasons for the emergency public health declaration announced last week.
Officials are hoping to get more people protected before the Passover holiday.
A judge in Brooklyn rejected a petition from five mothers trying to block the city's mandatory vaccinations.
Measles starts like a cold but symptoms escalate quickly.
"Some coughing, red eyes, then they quickly develop high fever 104, 105, then they usually begin to actually have this bright red rash, which usually starts on the face, and the head and the neck, and usually spreads down to the trunk and extremities," said Dr. Camille Sabella, Cleveland Clinic.
Complications include swelling of the brain.
In New York, several people are in intensive care.
Meanwhile, Israeli news media reports a flight attendant and a 10-year-old boy are both in comas, due to measles.
The 43-year-old flight attendant was vaccinated as a child, but back then, only one dose was required.
One dose is 93-percent effective. Two doses are 97-percent effective.
In the United States, the current recommendation for two doses was issued in 1989.
From 1963 until then, it was one dose. Adults may have received a second dose later.
If you were born before 1960, you may have never been vaccinated. It's assumed you were already exposed.
If you're unsure, ask your doctor, especially if you work in healthcare or plan to travel out of the country.
Officials continue to work to control measles outbreak