Editor’s note: This story was updated May 22 with new data on the growing number of measles cases.
March 10, 2025 — That cough or runny nose might just be a cold – but what if it’s measles? A growing number of Americans may find themselves asking this question.
Thirty U.S. states have had measles cases this year, including Texas, where two children have died from measles. A third measles death in New Mexico has also been confirmed, according to the CDC. The CDC has reported 1,024 measles infections so far in 2025, far exceeding the total number of cases in all of 2024 (285).
Measles spreads easily among people without immunity — those not protected by a past measles infection or by the MMR vaccine (for measles, mumps, and rubella). Two doses of that are 97% effective at preventing measles.
Measles is extremely contagious.
“Most viruses don’t linger in the air for hours after somebody has coughed or sneezed. Measles does,” said James Conway, MD, director of the Office of Global Health at the University of Wisconsin-Madison School of Medicine and Public Health.
If you’re not vaccinated, measles is easy to catch, but it can be difficult to spot in its early stages. The first symptoms don’t appear until 11 to 12 days after exposure and can be easy to dismiss. You might think you’re OK or just have a regular cold or flu.
In a recent case in Kentucky, a person infected with measles unknowingly exercised at a gym while contagious. “This is somebody who got home from travel, was infected by measles, and was capable of working out for three hours at a Planet Fitness on President’s Day,” said Conway. Health officials issued an alert to anyone who had been at the gym.
Measles sometimes takes a deadly turn. We asked doctors and researchers how to tell if you have measles and what to do next.
Are the Symptoms of Measles Obvious?
Eventually, measles causes telltale symptoms, like a blotchy red rash that starts on your face before traveling down your body. Tiny white or gray spots can also appear inside your mouth. Unfortunately, these visible symptoms aren’t early warning signs – they don’t show up until two to four days into the illness.
The first symptoms of measles, like a fever, cough, pink eye, and runny nose, can feel like a run-of-the-mill respiratory virus. Measles might not cross your mind.
“For many people, they heard about measles or read about it in Little House on the Prairie, but they can’t imagine that it’s something that’s a real threat,” said Conway.
Even doctors might miss it at first. “Measles can be a very difficult diagnosis, given the timing and nature of symptoms,” said Erik Blutinger, MD, MSc, assistant professor of emergency medicine at the Mount Sinai Icahn School of Medicine. People with early measles symptoms might undergo multiple tests to rule out other causes, he said. It might take more than one visit before a doctor orders a measles test.
But it’s this early symptom period, known as the prodrome, when you can put others at risk. “Measles is most contagious in the prodromal illness,” said Walter A. Orenstein, professor emeritus at the Emory University School of Medicine.
How Do Measles Symptoms Progress?
By the time the itchy, painful measles rash appears, other symptoms might be escalating. “For most people who get measles, it’s a fairly significant illness,” Orenstein said. “It’s not trivial.”
Measles can cause a fever of 104 or 105 degrees, intense cough, ear infections, diarrhea, and pneumonia that requires hospitalization. “As the virus spreads throughout the whole body, it certainly has a predilection that it likes to cause inflammation throughout the lining of the lungs,” said Conway.
The virus can also infect your central nervous system. About one in 1,000 children with measles develop encephalitis, or swelling in the brain. “They have a rip-roaring headache – it’s almost like having meningitis,” said Conway. “Some will even get neurologically impacted to the point where they’re confused or almost nonresponsive.” Severe cases can cause permanent hearing loss or intellectual disability.
Then, there’s the worst-case scenario: One to three of every thousand infections causes death.
There’s no antiviral medication for measles. Health care providers can only provide supportive care, like IV fluids for dehydration or vitamin A to support depleted immune function.
Even people who fully recover can struggle for a long time, said Conway, who has treated children with measles in the United States and abroad.
“These little kids just cry for days,” said Conway. “Every kid I’ve ever seen, they’re just miserable. They gradually recover, but they take a pretty big hit, and then their nutrition is down for a while because they don’t eat and drink very well. The GI tract is a mess. Their lungs are a mess. And so the recovery is, for many of these kids, a couple of months.”
Adults can suffer, too. “Measles can easily become a severe illness to anybody, especially those that are considered high risk for contracting the illness, like health care workers, pregnant individuals, those with immunocompromised systems,” said Blutinger.
Measles kills immune cells and causes lasting damage. “Another risk is what’s called post-measles immune amnesia,” said James D. Cherry, MD, MSc, a Distinguished Professor of Pediatrics at the David Geffen School of Medicine at UCLA. “When you have measles, you’re more susceptible to other infectious diseases for a period of up to up to five years.”
What Should I Do if I Think I Might Have Measles?
If you’re sick and live where measles is spreading – info you can find from the CDC website or your local public health department – contact your doctor for advice. If a viral illness keeps getting worse or you develop red eyes or a rash, call your doctor’s office, said Conway. They might recommend a measles test. They’ll also ask whether you’ve been vaccinated and help you trace your steps to see if you’ve potentially exposed anyone else.
Your doctor might watch your symptoms closely to see if you need extra help. One in eight people who have gotten sick in this year’s outbreaks have gone to the hospital, the CDC reports. When measles leads to hospitalization, it’s for treatment, not quarantine. “We generally try to do everything we can to avoid admitting these kinds of patients to the hospital unless we absolutely have to because measles is by far the most contagious thing on the face of the Earth that we know of at this point,” said Conway.
If you suspect you’ve been exposed to measles, contact your doctor immediately. Discuss your vaccine or infection history and ask whether you and your exposed loved ones are eligible for post-exposure prophylaxis to help fight the virus. Depending on your immune status and underlying conditions, your doctor may recommend an MMR vaccination within three days of the exposure, or measles immunoglobulin, which contains antibodies to boost your immunity, within six days of the exposure.
“For persons who are not immune, have an unknown immune status, or are immunocompromised, it is especially important to react quickly so that you don’t miss that window of opportunity where you might be able to prevent the infection, or at least make it less severe,” said Margaret Doll, PhD, MPH, associate professor of epidemiology at the Albany College of Pharmacy and Health Sciences.
Wear a mask anywhere you go, but especially at a health care facility, to protect others, said Conway. The average person with measles can infect more than a dozen other people.
Remember the long incubation period for measles. It could take two weeks after an encounter with an infected person before you start feeling sick. “There is this sort of recency phenomenon, where people have this idea that if I’m around somebody who’s got a cold, if I don’t come down with the cold symptoms in like three to five days, I’m probably good,” said Conway. “It doesn’t work like that for measles.”
How Can I Avoid Measles?
“The first thing every family should do is make sure everybody in the family is up-to-date with their vaccines,” said Conway.
Check your vaccine records – don’t just assume you’re covered, recommends Conway. Sometimes, adults check and find they didn’t get all the shots they (or their parents) thought. If you haven’t had two doses of the MMR vaccine or you’re not sure, ask your doctor about a booster.
Measles vaccination protects you and others who can’t get the vaccine, like infants or people with compromised immune systems, plus the 3% of people who don’t mount a sufficient immune response after vaccination.
How are they protected? They’re protected if they’re not exposed,” said Orenstein. “So community immunity or community protection is important because if a transmitting case only comes in contact with an immune population, the chain of transmission is broken.” (Learn more about how to protect yourself from measles.)
Following the COVID pandemic, pediatric vaccinations have declined in the U.S. “Given these trends, it’s not surprising that we’re having measles outbreaks,” said Doll. “Measles is a highly infectious disease, and it requires a high percentage of our population to be vaccinated to maintain that herd immunity threshold that stops the transmission of measles.”
Orenstein was the director of the United States Immunization Program from 1988 to 2004. “Since 2000, we’ve been able to maintain elimination, meaning any introduction of measles gets terminated in less than a year,” he said. “None of them have continued for more than a year.”
What does he think about the state of measles – and vaccine hesitancy – in the U.S. today?
“It is very, very sad,” said Orenstein. “The problem is prevention can be a much harder sell than therapy. Plus, with a successful prevention program, people don’t realize they’re getting any benefits, and we have had a very successful prevention program with regard to measles.”
Outbreaks are a reminder of why prevention matters. “The problem is, sometimes we think we’ve completely gotten rid of measles, but that’s not the case,” said Orenstein.