(NBC News) – Confirmed cases of the measles in the U.S. continues to rise.
New CDC data shows that there are now 839 cases in 23 states as of last Friday.
That is an increase of 75 cases from the week before.
Nearly 700 of the cases have been reported in New York with the majority being among unvaccinated people in Orthodox Jewish Communities.
Health officials say this is the worst measles outbreak the country has experienced in a quarter of a century.