Colorado's Measles Outbreak Ends as US Cases Continue to Decline

Health officials in Colorado have declared that the state's measles outbreak has concluded. Over the past weeks, the intense surge of cases has subsided, contributing to a nationwide decrease in weekly measles infections. In the last week alone, the United States reported just 10 new confirmed cases, marking a significant decline compared to previous months when outbreaks were more widespread.

As of July 24, 2025, the total number of measles cases in the U.S. has surpassed the total for 2019, a year when the country was close to losing its measles elimination status, according to the CDC. Most cases this year are concentrated in Texas, where an outbreak earlier in the year led to over 762 infections across 36 counties, primarily affecting an undervaccinated Mennonite community. Despite no new cases in Texas for the past week, the outbreak's impact was substantial, including fatalities—an 8-year-old child succumbed to measles pulmonary failure, highlighting the dangers unvaccinated individuals face.

Other states experiencing outbreaks include Arizona, Georgia, Iowa, Kansas, Kentucky, Michigan, Missouri, Montana, New Mexico, Oklahoma, and Utah. For example, Arizona's cases in Navajo County are linked to recent travel and unvaccinated individuals, while Michigan has several active outbreaks in counties like Grand Traverse. In Montana, cases have increased to 27, with some counties experiencing their first outbreaks in decades. Notably, Canada and Mexico are also battling large outbreaks, with thousands of cases and several deaths, emphasizing the broader North American challenge.

Vaccination remains the most effective method of prevention. The MMR vaccine, typically administered in childhood, provides herd immunity when vaccination rates exceed 95%. However, vaccine hesitancy and declining vaccination coverage have contributed to these recent outbreaks. Adults who haven't received the MMR vaccine or aren't sure of their immunity are encouraged to get vaccinated to protect themselves and others.

Symptoms of measles include high fever, cough, runny nose, red watery eyes, and a characteristic rash that appears three to five days after initial symptoms. Complications such as pneumonia, blindness, brain inflammation, and death can occur, particularly in unvaccinated vulnerable populations. Since no specific treatment exists, medical care focuses on alleviating symptoms and preventing complications.

Overall, while Colorado's outbreak is now over, the risk of measles persists due to ongoing cases in various states and neighboring countries. Maintaining high vaccination coverage is crucial to prevent future outbreaks and protect public health.