The measles outbreak in the United States has reached a critical point, with 1,168 confirmed cases across 34 jurisdictions as of June 5—surpassing the total number of cases recorded in all of 2024.
In response, the Centers for Disease Control and Prevention (CDC) has issued an updated travel advisory, urging Americans—especially international travelers and healthcare providers—to ensure they are fully vaccinated. Public health officials continue to emphasize the importance of the measles, mumps, and rubella (MMR) vaccine, which is highly effective in preventing infection and curbing community spread.
High vaccination rates play a vital role in protecting vulnerable populations, including individuals who cannot receive the vaccine due to immunocompromising conditions or medical treatments.
The CDC reports that the vast majority of this year’s cases—95%—occurred in individuals who were either unvaccinated or whose vaccination status is unknown. To date, 778 of the cases have been in children and young adults under the age of 20. Approximately 89% of infections are linked to 17 separate outbreaks across the country, with 137 people requiring hospitalization.
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West Texas has emerged as the epicenter of the outbreak, with 742 reported cases. New Mexico follows with 81 confirmed infections. Tragically, two unvaccinated children in West Texas and one unvaccinated adult in Lea County, New Mexico, have died as a result of the disease.
The CDC has confirmed cases in the following states: Alaska, Arkansas, California, Colorado, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, New Jersey, New Mexico, New York (both the city and the state), North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Tennessee, Texas, Vermont, Virginia, and Washington.
A Global Concern
The domestic surge is part of a broader global resurgence of measles. According to a joint report from the World Health Organization (WHO) and UNICEF, more than 127,000 measles cases were reported across 53 countries in Europe and Central Asia in 2024—double the number seen in 2023 and the highest since 1997. Over half of the reported European cases required hospitalization, and 38 measles-related deaths were recorded.
Globally, nearly 360,000 cases of measles were reported in 2024, reflecting a troubling trend tied to declining vaccination rates and persistent misinformation.
CDC Travel Advisory and Guidance
Given the expanding outbreak, the CDC has issued a travel advisory for U.S. residents. The agency stresses that international travelers should be fully vaccinated against measles, and that individuals aged six months and older without documented vaccination or proven immunity should receive the MMR vaccine before traveling abroad.
“Travelers can catch measles in many settings—including travel hubs like airports and train stations, on public transportation, and at crowded tourist attractions and events,” the CDC warned. Travelers are advised to monitor for symptoms for 21 days after returning from international travel.
Dr. Anne Liu, clinical associate professor of pediatrics, immunology, and allergy at Stanford University, underscored the seriousness of the outbreak:
“Measles is a highly contagious disease that can turn deadly. People who are unvaccinated and people who are immunocompromised should be quite concerned about the growing footprint of this outbreak.”
As the U.S. and other nations confront rising case numbers, health officials continue to advocate for strong vaccine coverage as the most effective defense against a disease once declared eliminated from the country.
Vaccination: The Only Proven Defense Against Measles
Experts say the rapid spread of measles in the U.S. and abroad comes down to one stark fact: measles is one of the most contagious diseases known to medicine.
“It’s unbelievably contagious. It’s the most contagious disease we’ve ever seen,” said Dr. Danelle Fisher, a pediatrician at Providence Saint John’s Health Center in Santa Monica, California.
Measles can spread easily even before symptoms appear. Infected individuals are contagious for about four days before the onset of symptoms and remain contagious for up to 10 days after, making it extremely difficult to contain without widespread immunity.
Dr. William Schaffner, an infectious disease expert and professor of medicine at Vanderbilt University, emphasized that vaccination is the only effective method of prevention.
“Vaccination is the way to prevent measles. There are no other ways,” Schaffner said. “Although it’s been mentioned in the news, vitamin A cannot prevent measles.”
Dr. Fisher echoed that sentiment, noting that people who have been fully vaccinated or have had measles in the past are highly protected.
“If you’re fully vaccinated, you’re not going to get sick and you’re not going to spread it,” she said.
However, those who are unvaccinated—or whose immunity has waned over time—face a significantly higher risk of infection and complications. Dr. Fisher likened the current situation to the early days of the COVID-19 pandemic, before vaccines were available.
“If we didn’t have a vaccine for measles, this outbreak could have swept across the globe in just a few weeks,” she said. “Vaccination is the reason this isn’t spreading even more widely.”
Both experts stressed the importance of vaccination not only for individual protection but also for safeguarding the broader community, especially those who cannot receive the vaccine for medical reasons.
“Parents should make sure their children are up to date on their vaccines,” Fisher advised. “Adults who are unvaccinated or unsure of their vaccination status should also get immunized.”
“It’s incumbent on all of us to protect the most vulnerable in our society,” she added.
Dr. Schaffner agreed, underscoring the community-wide responsibility that comes with vaccination.
“There are many children and adults among us who are immunocompromised,” he said. “If they were to contract measles, they could become severely ill. We protect them by being vaccinated ourselves, creating a cocoon of protection that makes it harder for the virus to reach them.”
Additional Precautions to Reduce Measles Risk
While vaccination remains the most effective way to prevent measles, experts emphasize that unvaccinated individuals—whether by choice or due to medical exemptions—should take additional steps to lower their risk during the current outbreak.
Dr. Danelle Fisher, a pediatrician at Providence Saint John’s Health Center, advised that those who are unvaccinated avoid non-essential travel, particularly by plane, train, or other forms of mass transit, where exposure to large groups of people is difficult to avoid.
“If you’re unvaccinated, you should limit travel to essential purposes only,” she said.
Workplace settings also warrant caution, especially for people who spend time in high-risk environments such as schools, childcare centers, or healthcare facilities. Fisher recommends that unvaccinated individuals explore options to reduce close contact with others in these settings when possible.
In everyday situations, vigilance around symptomatic individuals is crucial. Fisher stressed the importance of avoiding close proximity to anyone showing signs of illness, especially coughing or other symptoms consistent with respiratory infections.
“Be very wary of anyone with any kind of upper respiratory illness,” she warned.
Even routine errands, such as grocery shopping, could pose a risk for those without measles immunity. As the outbreak continues to expand, Fisher cautioned that public spaces may become increasingly unsafe for unvaccinated individuals.
“As this outbreak spreads, the areas of safety are going to get smaller and smaller,” she said.
Ultimately, while situational precautions can help reduce exposure, health experts agree that vaccination offers the strongest and most reliable protection—both for individuals and the communities they live in.
What to Know About Measles
Before the measles vaccine became widely available in the mid-20th century, the virus caused more than 3 million infections annually in the United States, leading to approximately 48,000 hospitalizations and 500 deaths each year.
Thanks to widespread vaccination, those numbers dramatically declined. However, recent outbreaks are a stark reminder of the risks posed when vaccination rates drop.
The Centers for Disease Control and Prevention (CDC) recommends that all children receive two doses of the measles, mumps, and rubella (MMR) vaccine. The first dose is typically administered between 12 and 15 months of age, with a second dose given between ages 4 and 6. These two doses are over 97% effective at preventing measles.
How Measles Spreads
Measles is highly contagious and spreads through airborne respiratory droplets or by direct contact with surfaces contaminated by those droplets. An infected person can transmit the virus before symptoms even appear, making early prevention through vaccination critically important.
Common Symptoms and Potential Complications
Symptoms of measles typically appear within 7 to 14 days after exposure and may include:
- A widespread skin rash
- High fever
- Persistent cough
- Sore throat
While many cases resolve without severe complications, roughly 30% of infections lead to additional health issues. Common complications include ear infections and diarrhea. In more serious cases, measles can cause:
- Pneumonia (a leading cause of measles-related deaths in young children)
- Encephalitis (inflammation of the brain, which can lead to permanent brain damage)
- Subacute sclerosing panencephalitis (a rare but fatal brain disorder that can occur years after infection)
Dr. Anne Liu, a clinical associate professor at Stanford University, noted another long-term concern: the virus can impair immune memory, leaving individuals susceptible to illnesses they previously had immunity against.
“One of the lesser-known features of measles is that it can wipe out part of a person’s immune memory from prior infections,” Liu said. “These are preventable illnesses.”
She emphasized that many current hospitalizations are due to the severity of illness—not just quarantine precautions—and urged the public to take the threat seriously.
Dr. William Schaffner echoed that message, calling for increased awareness and community support for vaccination efforts.
“The public should be aware of the current measles situation,” he said. “Stay informed and make sure you and your family are fully vaccinated. If you have friends who are hesitant about vaccinating their children, encourage them to talk with their doctor. Help them feel supported in making a decision that protects not only their family, but the community as a whole. We’re all in this together.”
Frequently Asked Questions
Why are measles cases rising in so many states?
The increase in measles cases is primarily due to declining vaccination rates, vaccine misinformation, and ongoing vaccine hesitancy. Measles is highly contagious, and even small gaps in immunity can lead to outbreaks.
How contagious is measles?
Measles is one of the most contagious diseases known. An infected person can spread the virus to 90% of nearby unvaccinated individuals. People can transmit measles before symptoms appear, which makes containment challenging.
Who is most at risk during this outbreak?
Individuals who are unvaccinated, under-vaccinated, or have weakened immune systems are at the highest risk. Young children and adults without immunity are particularly vulnerable to serious complications.
How effective is the measles vaccine?
The measles, mumps, and rubella (MMR) vaccine is highly effective, providing about 97% protection after two doses. Vaccination is the best way to protect yourself and prevent the spread of measles.
Can vaccinated people still get measles?
While rare, vaccinated individuals can sometimes contract measles, but their cases are usually milder and less likely to spread the disease. Most outbreaks occur among unvaccinated populations.
What symptoms should I watch for?
Early symptoms include high fever, cough, runny nose, and red eyes, followed by a distinctive red rash that usually starts on the face and spreads. If you or your child develop these symptoms, contact a healthcare provider immediately.
Conclusion
The resurgence of measles across the United States is a clear warning: preventable diseases can return—and spread rapidly—when vaccination rates decline. With over a thousand confirmed cases and outbreaks now reported in more than 30 states, the urgency for action is real.
Vaccination remains the most effective defense, not only for individual protection but also to safeguard vulnerable populations who cannot be immunized due to age or medical conditions. Alongside vaccination, public awareness, responsible travel, and caution in public spaces are essential in slowing the virus’s spread.
