US measles surge hits highest level since 1991

The US is facing its worst measles resurgence in over three decades. 

According to the latest Centers for Disease Control and Prevention (CDC) data, as of October 8, 2026, the country had registered 4,080 confirmed measles cases this year – nearly double the 2,289 cases recorded in all of 2025. This is the highest annual total since 1991, driven by 42 active outbreaks across 47 jurisdictions.

Of the total cases, 4,062 were reported across US jurisdictions, with an additional 18 involving international visitors. To date, 414 patients have been hospitalized, accounting for approximately 10% of total confirmed cases.

Unvaccinated individuals remain the primary drivers of this crisis, accounting for 95% of confirmed cases. School-aged children and teenagers aged 5 to 19 constitute the largest affected demographic at 42%, followed closely by adults aged 20 and older at 40%. Rising hospitalizations have heightened concern, as hospitalizations climbed to 414, representing roughly 10% of total cases, compared with 244 recorded in 2025.

Pennsylvania has become the outbreak's epicenter, reporting 1,136 cases, 219 hospitalizations and five deaths this year – the largest state-level outbreak in over 30 years. Meanwhile, New York declared a statewide disaster emergency after reporting 108 cases, expanding testing and vaccination access to contain local spread.

Measles is a highly contagious airborne respiratory illness that can lead to severe complications like pneumonia. The US CDC emphasizes that the measles, mumps and rubella (MMR) vaccine is the best defense, noting that community vaccination rates above 95% are required to achieve herd immunity.