The nationwide measles outbreak has now hit nearly 700 cases across 22 states.
The centers for disease control and prevention says that’s the highest number of reported cases in 25 years.
New York City health officials announced at least 31 more cases Wednesday including two pregnant women.
The measles virus was declared eliminated in the US in 2000.
But it has returned several times including in 2014 when 667 cases were reported.
Health officials are now blaming the outbreak on mis-information about the vaccine which is considered safe and highly effective.
The CDC is urging anyone who is not vaccinated to do so.