Which disease made a major resurgence in the U.S. in 2025, with over 1,300 cases reported by July -- the most since 1992?

Measles made this major resurgence in the U.S. in 2025, driven largely by outbreaks in communities with lower vaccination rates, particularly in Texas and New Mexico. Measles is extremely contagious and spreads easily through the air, which is why gaps in vaccination coverage can let it surge quickly once it reaches an unprotected community.

Whooping cough and mumps are both real vaccine-preventable diseases that can also cause outbreaks, but the disease that specifically drove this record-breaking surge past 1,300 cases and the worst numbers seen in more than three decades was measles.

Because the outbreak grew large enough and lasted long enough, the Americas region as a whole ended up losing its official status as having eliminated measles, a designation it had held for years.