The measles outbreak in the United States achieved a particular milestone this month. Health officials said they had seen 288 cases of the disease between Jan. 1 and May 23 of this year, the most in any year since the disease was declared eliminated in 2000. That’s also the first time the Centers for Disease Control and Prevention has seen this many cases this early in a year since 1994 (when 764 people were infected over the same span). Nearly every measles case involved an unvaccinated person traveling outside the U.S.
This chart from the CDC outlines just how severe this year’s outbreak has been, particularly so early in the year: