US Measles Cases Hit 35-Year High at 2,295, Surpassing All of Last Year

The US has recorded 2,295 measles cases in 2025 — the highest count in over 35 years — already surpassing last year's full annual total.

The United States is experiencing its worst measles outbreak in more than three decades, with 2,295 confirmed cases recorded so far this year, according to Johns Hopkins University's measles tracker. That figure already exceeds the country's total case count for all of last year, marking a significant acceleration in transmission. In Arizona, Maricopa County health officials have identified new public exposure sites including Chase Field — home of the Arizona Diamondbacks — where a concert was held, and an East Valley mall identified as Chandler Fashion Center. Anyone who attended these venues during the identified exposure windows may have come into contact with an infected individual. Measles was declared eliminated in the United States in 2000, meaning there was no longer continuous year-round transmission. Outbreaks since then have been tied primarily to unvaccinated individuals and international travel. The MMR (measles, mumps, rubella) vaccine is approximately 97% effective after two doses.

Why it matters

Measles is one of the most contagious diseases known, capable of infecting up to 90% of unvaccinated people exposed to it. A sustained rise in cases at this scale raises concern about erosion of the herd immunity threshold needed to protect infants and immunocompromised individuals who cannot be vaccinated.

What's next

Health officials are urging anyone who visited the identified Maricopa County exposure sites to check their vaccination status and monitor for symptoms including fever and rash.

Key facts

• 2,295 measles cases have been recorded in the US so far in 2025, per Johns Hopkins University's tracker
• The case count is the highest in more than 35 years — since before measles elimination was declared in 2000
• The 2025 total has already surpassed the entire annual case count for 2024
• New exposure sites in Maricopa County, Arizona include Chase Field (a concert venue) and a Chandler-area mall
• Measles was officially declared eliminated in the US in 2000

Bias & framing notes

Both sources report factual developments without overt editorializing. The Hill focuses on the national statistical milestone sourced to Johns Hopkins University, a credible academic tracker. AZ Family provides local public-health reporting on specific exposure sites, citing county health officials. Neither source provided significant context on the causes driving the surge — such as vaccination rate trends or specific outbreak clusters — limiting the depth of the combined picture.

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