Tracking the Measles Outbreak:

The latest news on an increasing, but preventable, measles epidemic in the United States.

Image credit: Povorozniuk Liudmyla and Getty Images.

According to the most recent Centers for Disease Control and Prevention (CDC) data, as of Friday, May 9^th, the United States (US) has recorded the most measles cases in a single year since a 2019 infectious disease outbreak.

Nationwide, measles cases have surpassed 1,001, with confirmed infections in at least 31 states. Those jurisdictions are as follows: Alaska, Arkansas, California, Colorado, Florida, Georgia, Hawaii, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Missouri, Montana, New Jersey, New Mexico, New York City, New York State, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Texas, Vermont, Virginia, and Washington.

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This is a map of Texas counties showing those (in red) that have had measles cases recorded by health officials this year as of April 22nd, 2025. The numbers have since increased and continue to rise unabated. Image credit: The Texas Department of State Health Services.

The number of measles cases in Texas alone has risen to over 700, with reports now indicating the deaths of two children in the epicenter of the epidemic, West Texas.

Texas state and local health officials verified that the first patient who died was an unvaccinated child of school age, and the second was an unvaccinated 8-year-old girl. The Texas Health Department reported that neither of the children had underlying health conditions.

Almost all children and teenagers infected in the Texas outbreak were either unvaccinated or had an unknown vaccination status. New Mexico has also reported the death of an adult due to measles.

In recent years, the most confirmed measles cases in the US occurred in 2019, peaking at 1,274 due to outbreaks in New York, California, and Washington.

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The Seminole Hospital District in Seminole, Texas. Image credit: Jule Cortez and the Associated Press (AP).

Before 2025, the last measles death in the US was also in 2019.

In most other years, however, the total has been much lower. One of the key drivers behind the fall in vaccination rates is the relentless spread of conspiracy theories about vaccine safety.

Current Department of Health and Human Services Secretary Robert F. Kennedy (RFK) Jr. and other “wellness influencers” are spreading misinformed narratives claiming that vaccines cause autism, contain dangerous substances, or are tools of government control.

These “anti-vaxx” theories, amplified by Mr. Kennedy, other influential anti-vaccine activists, and social media algorithms, have sown deep mistrust in vaccinations among specific segments of the American population. Research from the American Journal of Public Health reveals that exposure to anti-vaccine content on social media correlates with higher rates of vaccine hesitancy.

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Image credit: NEJM.org.

Social media platforms like Facebook, Instagram, and Truth Social have been particularly fertile grounds for such misinformation.

Notably, disinformation campaigns have exploited political and cultural divisions, framing vaccination as a matter of personal freedom rather than public responsibility. This disinformation is not harmless.

A 2023 Kaiser Family Foundation survey found that nearly 30% of American adults believed at least one vaccine-related conspiracy theory, and 17% of parents expressed hesitation or refusal to vaccinate their children against measles.

Measles requires about 95% vaccination coverage to maintain herd immunity — a level that protects even those who cannot be vaccinated, such as infants and immunocompromised individuals. As conspiracy theories erode public trust and funding cuts limit outreach and vaccination efforts, some communities have seen coverage dip below 90%, creating fertile ground for outbreaks.

The public health consequences extend beyond measles. Reduced confidence in vaccines contributes to mass vulnerability to other preventable diseases like mumps, rubella, and even polio, which saw its first U.S. case in nearly a decade in 2022.