U.S. Measles Outbreaks: A New Abnormal in a Time of Vaccine Hesitancy

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The U.S. first achieved measles elimination status – defined as “the absence of endemic [continued transmission of] measles for a year or more in the presence of a high-quality surveillance system” – in 2000. Since then, it has sometimes come dangerously close to losing that status, particularly in 2019, and we may be going in that direction again.  We’re only two months into 2025, and already the U.S. is confronting a large, growing measles outbreak in Texas – which has led to the first known measles death in the U.S. since 2015 – as well as other reported cases in Alaska, California, Georgia, Kentucky, New Jersey, New Mexico, New York City, and Rhode Island. Thus far, the CDC has reported 164 measles cases this year compared to 285 cases all of last year (which was the highest total since 1,274 in 2019.) More generally, measles cases in the U.S. have been on the rise, and the overall trend of growing risk is unmistakable. Most at risk from the severe effects of measles are children; it is recommended that children in the U.S. be protected from the disease through two doses of a safe and effective measles, mumps, and rubella (MMR) vaccine.

There is no secret about why outbreaks are happening more frequently: it’s because there are more unvaccinated children. U.S. vaccination rates, including for the MMR vaccine, have declined since 2010. Exemptions from childhood vaccinations have increased. (An increase in measles globally is also a factor due to greater chances of imported cases seeding new outbreaks here). Vaccine skepticism and misinformation among individuals and families, particularly in the wake of COVID-19, have contributed to declining coverage. As shown in KFF polls, a growing share of parents (including a quarter of Republican parents) now agree with the statement, “The risks of childhood vaccines for measles, mumps, and rubella outweigh the benefits.” In addition, reflecting changing attitudes and politicization of public health during and after the pandemic, more states have passed legislation that relaxes childhood vaccine requirements and/or allows more non-medical exemptions (with many more such bills introduced in state legislatures in recent years). One result has been growth in non-medical vaccine exemptions for school-age children (see Figure), which made up almost all the increase in all vaccine exemptions between the 2019-2020 and 2023-2024 school years.

So far, the Trump Administration has not demonstrated much urgency in response to the situation. On February 27, the Centers for Disease Control and Prevention released a short statement about the Texas measles outbreak, “Vaccination remains the best defense against measles infection.” This week Secretary of Health and Human Services Robert F. Kennedy Jr. commented that measles outbreaks are “not unusual,” but did not mention vaccinations. Kennedy has a history of speaking out against the measles vaccine and has repeatedly linked MMR vaccination with the development of autism (a link that has been proven again and again not to exist). In recent weeks, he has suggested that as HHS Secretary, he would revisit the vaccine schedule recommended by the CDC after promising not to change it during his confirmation hearings. All of this is a notable contrast from the first Trump Administration, which had proactive messaging in support of measles vaccination during the outbreak in 2019.  Given the current trends and embrace of vaccine skepticism on the part of the administration, and potential changes to federal policy around childhood vaccines, we might continue to witness more and longer outbreaks of preventable disease—and just maybe lose our measles elimination status, which as a country we’ve had for 25 years.