Measles Is Surging Again. What Does the Science Say About Vaccination?
As measles cases surge in the U.S., explore the science behind the MMR vaccine, why outbreaks happen, and what students and schools should know.
Introduction
The United States eliminated measles in 2000, which was a major public health achievement made possible by widespread vaccination. Twenty-six years later, however, we’re seeing the highly contagious disease spread again.
The Centers for Disease Control and Prevention had confirmed 2,566 measles cases across the U.S., including 38 outbreaks, as of Aug. 14—exceeding the 2,289 cases reported in 2025. Ninety-four percent of this year’s cases have been connected to outbreaks. Measles can cause serious illness, disability and death, and vaccination is the most effective way to prevent its spread.
The resurgence comes as President Donald Trump and Department of Health and Human Services Secretary Robert F. Kennedy Jr. have moved to revise the childhood immunization schedule, which lowers the number of required vaccines and spaces them out over more appointments—a policy change critics say will lead to a drop in vaccination rates.
What’s Happening?
Measles is one of the most contagious diseases in the world. It spreads through the air when an infected person coughs or sneezes, and the virus can remain infectious in the air for up to two hours after that person leaves a room, according to the World Health Organization.
For decades, widespread use of the measles, mumps and rubella (MMR) vaccine kept the disease uncommon in the U.S. But vaccination rates have fallen. CDC data show that MMR coverage among U.S. kindergartners dropped to 92.4 percent for the 2025-26 school year, compared with 95.2 percent in the 2019-20 school year.
Only 10 states reported vaccination rates above 95 percent (a rate public health officials identified as strong enough to generate community protection) in the 2024-25 school year, ranging from 78.5 percent in Idaho to 98.2 percent in Connecticut, according to Johns Hopkins Bloomberg School of Public Health.
When vaccination levels decline—particularly within individual communities—the virus has more opportunities to spread. Children and adults who can’t be vaccinated due to being immunocompromised, like having cancer, can more easily get sick and die if they contract measles.
Under Kennedy, a longtime vaccine skeptic, and the Make America Healthy Again initiative, the Trump administration has overhauled parts of federal childhood vaccine policy to increase choice among families.
What Does the Science Tell Us About Measles?
Measles is sometimes remembered as a routine childhood illness from an earlier era. But before widespread vaccination, it caused tens of thousands of hospitalizations and hundreds of deaths in the U.S. each year, according to the CDC.
Many people recover, but there is no way to know in advance who will develop a severe complication. Measles can cause pneumonia and encephalitis, or swelling of the brain. Brain inflammation can result in lasting neurological damage. The disease can also cause hearing or vision loss, and WHO identifies blindness and brain damage among possible measles complications.
There is also a rare but devastating complication called subacute sclerosing panencephalitis, or SSPE. According to the CDC, it can develop seven to 10 years after someone appears to have fully recovered from measles. SSPE progressively damages the brain and is fatal.
Measles can weaken immune defenses after the initial infection, leaving people more vulnerable to other diseases. Despite the federal government’s changes to vaccine guidance, the evidence for measles vaccination is extensive.
According to the CDC:
- One dose of MMR vaccine is about 93 percent effective at preventing measles.
- Two doses are about 97 percent effective.
No medical intervention is completely without risk. MMR can cause temporary side effects such as soreness, fever or a mild rash; in extremely rare cases, serious reactions can occur.
Why Is This Important for Schools?
A vaccine schedule answers several different questions: Which vaccines should people receive? At what age? How many doses are needed? And can different vaccines be given at the same visit?
Schools bring hundreds or thousands of people into close contact every day, making vaccination levels especially important for diseases as contagious as measles.
High vaccination rates also help protect people who cannot receive certain vaccines, including some children with compromised immune systems and infants who are too young for routine vaccination.
This is the idea behind herd immunity: When enough people are protected, a virus has fewer opportunities to travel from one susceptible person to another. Outbreaks often happen when a given community has a lower vaccination rate. For educators, students and families, that makes distinguishing credible health information from political claims, rumors and misinformation particularly important.
Discussion Questions
- Why do you think measles cases can return even after the disease was declared eliminated in the U.S.?
- What is the difference between debating how a vaccine should be administered and debating whether vaccination works?
- Why might public officials in different administrations make different decisions about vaccine schedules even when they are looking at some of the same scientific evidence?
- How should policymakers balance parental choice with the fact that vaccination against contagious diseases can also protect other members of a community?
- What information would you want to see before deciding whether a claim about vaccine safety is trustworthy?
- The White House says its new approach is intended to increase trust and flexibility around vaccination. What might increase public trust in health recommendations? What might decrease it?
Media Literacy: Politics, Policy and Scientific Evidence
Vaccine coverage can be particularly challenging to evaluate because political arguments and scientific questions are often discussed together.
Choose two recent news stories about changes to the childhood vaccine schedule and compare them.
Consider:
- Does the headline distinguish between changes to the vaccine schedule and evidence about whether a particular vaccine is safe or effective?
- What scientific evidence does the article cite?
- Does it link to original sources such as the CDC, Food and Drug Administration, HHS or peer-reviewed research?
- Which statements are facts, and which are opinions or political arguments?
- Does the story explain the risks of the disease as well as possible vaccine side effects?
- Are statistics presented with enough context to understand the actual level of risk?
Then compare those articles with CDC or FDA information about MMR vaccination. What differences do you notice in language, emphasis and evidence?
Classroom Activity: Follow the Evidence
Divide students into small groups and assign each one a claim related to measles or vaccination—for example:
- Measles isn't dangerous for most children.
- If vaccinated people can still get measles, the vaccine doesn't work.
- Changing a vaccine recommendation means scientists discovered the old recommendation was unsafe.
- Vaccination only affects the person receiving the vaccine.
Ask students to investigate the claim using at least three credible sources, including one primary government or scientific source.
For each claim, students should identify:
- What the evidence actually shows.
- What information might be missing from the original claim.
- Whether the claim is accurate, misleading or unsupported.
- How they would rewrite it to accurately communicate the science.
Conclusion
Recommendations about vaccines can change as scientists study new evidence—and decisions about public health can also become entangled with politics.
That makes understanding the evidence itself especially important.
The federal government is reconsidering how some childhood vaccines are scheduled and administered. But its current recommendation still calls for children to be vaccinated against measles, and the underlying evidence remains strong: Measles is an extremely contagious disease that can cause hospitalization, permanent disability and death. The MMR vaccine is safe and highly effective at preventing measles.
At a moment when measles cases and debate about vaccines both are increasing, knowing how to separate scientific evidence, policy choices and political arguments is an important health—and media-literacy—skill.
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Amanda Eisenberg is the editorial lead for The 80 Million, a Medicaid newsletter powered by Manatt Health. She also supports Dr. Vin Gupta in his work with the American Federation of Teachers. In her free time, Amanda enjoys walking around New York City and reading. She's also the author of PEOPLE... See More
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