2025 has marked the worst year for measles in the U.S. since 1991, with over 1,300 cases reported across 40 states by mid-July, including a record-breaking outbreak in West Texas.

The West Texas outbreak, primarily linked to an undervaccinated Mennonite community, has resulted in over 700 cases, making it the largest cluster since measles was declared eliminated in 2000.

This surge in cases is compounded by declining vaccination rates, which have fallen below the herd immunity threshold of 95%, with some counties like Gaines County dropping to 82%.

In Gaines County, vaccination exemptions have increased significantly from 2% in 2014 to nearly 20% in 2024, contributing to the outbreak's spread.

Health experts stress that maintaining at least 95% vaccination coverage is crucial for community immunity, especially as measles is highly contagious and can infect 12 to 18 others from a single case.

Local vaccination clinics are actively promoting the MMR vaccine, which is 97% effective when both doses are administered, to combat the outbreak.

Tracking cases has been challenging due to reliance on voluntary reporting, which may lead to undercounting, and officials are emphasizing improved case reporting and community engagement.

Lessons learned from previous outbreaks, including a 2014 Ohio case, highlight the importance of better communication, case management, and community-specific outreach to control the spread.

So far in 2025, there have been three confirmed measles-related deaths, all unvaccinated individuals, including two children in Texas and one adult in New Mexico.

The outbreak's spread has been exacerbated by mobility and connections to communities in neighboring states and Mexico, with public health officials drawing on past experiences to improve response strategies.

Despite the recent surge, some areas like Sedgwick County, Kansas, currently report no active cases, but the overall situation remains concerning due to ongoing transmission.

The U.S. has also seen a decline in global vaccination efforts, which could further threaten domestic health security as international outbreaks continue.