Measles is among the most contagious diseases in the world, and case counts in the United States are spiking.
NBC News is tracking confirmed measles cases across the country with data from state health departments. The data will be updated every Tuesday and Friday.
With more than 500 cases, 2025 is already the third-most active year for measles since 2000, the year the United States officially eliminated it.
Most cases this year are in Texas, which accounts for 3 out of 4 reported infections.
“Elimination” means the disease has not spread continuously for at least 12 months. And while sporadic outbreaks have occurred since 2000, recent case counts are nothing compared with the 27,000 cases reported in 1990 or the 450,000 cases reported in 1964.
The measles vaccine was introduced in 1963, which marked a turning point for the contagious disease, which used to kill thousands every year.
