Yes, adults can get measles, and the infection is often more serious than it is in children

Measles does not stop being contagious once you turn 18. Adults who were never vaccinated, received only one dose of the vaccine, or lost immunity over time can catch measles from an infected person. The virus spreads through the air when someone coughs or sneezes, and it is highly contagious — about 9 out of 10 unvaccinated people exposed to measles will develop the infection.

What changes in adulthood is how your body handles the virus. Adults tend to have more severe symptoms than children, higher rates of complications like pneumonia and encephalitis (brain inflammation), and longer recovery times. Pregnant women who get measles face particular risks, including miscarriage and premature birth. This is why measles immunity matters more as you get older, not less.

Key Takeaways

  • Adults without measles immunity can catch the disease from a single exposure, since the virus spreads through the air and is extremely contagious.
  • Measles complications in adults include pneumonia, ear infections, and encephalitis, occurring in roughly one out of every four to five adult cases.
  • Two doses of the MMR vaccine (measles, mumps, rubella) given at least 28 days apart provide lasting protection for nearly all adults who receive them.
  • A blood test can show whether you are immune; if you are not, vaccination is the only way to build protection.
  • Adults born before 1957 are often considered naturally immune due to childhood measles exposure, though some health systems recommend one dose of vaccine even for this group.

Who is at risk for measles as an adult

Your risk depends on your vaccination history and whether you have had measles before. Adults who received two doses of the MMR vaccine are protected in nearly all cases. Those who received one dose have some protection but are more vulnerable than fully vaccinated people. Adults who were never vaccinated, or whose vaccination records are unknown, face the highest risk.

People born before 1957 are generally considered to have natural immunity because measles was common in childhood then. However, some health systems recommend one MMR dose even for this group, particularly if they work in healthcare or travel internationally. If you are unsure of your vaccination status, a blood test can determine whether you are immune.

Certain groups face higher consequences if they catch measles. Pregnant women are at risk for serious complications. People with weakened immune systems — from HIV, chemotherapy, or immunosuppressive medications — can develop severe disease. Adults over 20 have higher rates of complications than younger adults.

How measles spreads and how contagious it is

Measles spreads when an infected person coughs or sneezes, releasing virus particles into the air. You can catch it by breathing in those particles, or by touching a surface where the virus landed and then touching your face. The virus can survive on surfaces for up to two hours. A single infected person will infect about 12 to 18 unvaccinated people in the same space over time — far more contagious than flu.

An infected adult is contagious from about four days before the rash appears until four days after it appears. Many people spread measles before they realize they have it, during the early phase when symptoms look like a cold or flu. This is why measles outbreaks can grow quickly in communities with low vaccination rates.

Symptoms and complications in adults

Measles starts with fever, cough, runny nose, and red eyes — symptoms that look like a cold. Two to three days later, white spots appear inside the mouth (called Koplik spots), and then a red rash spreads from the face downward. Adults typically have higher fevers and more severe cough than children, and they feel sick for longer.

Complications occur in roughly one in four to five adult cases. Pneumonia is the most common serious complication, happening in about 6 percent of adults with measles. Encephalitis (inflammation of the brain) is rare but serious, occurring in about 1 in 1,000 cases. Ear infections, diarrhea, and temporary vision problems also happen. Pregnant women who get measles have higher rates of miscarriage and premature delivery. Most adults recover fully, but recovery takes several weeks, and some people feel fatigued for months afterward.

Vaccination and immunity for adults

The MMR vaccine is the only way to build measles immunity if you do not have it naturally. Adults need two doses given at least 28 days apart. After two doses, about 97 percent of vaccinated people are immune for life. One dose provides about 93 percent protection, which is why two doses are recommended.

If you are unsure whether you were vaccinated, you have two options: get a blood test to check immunity, or simply get vaccinated. The vaccine is safe for adults, and getting vaccinated when you are already immune does not cause problems. Many adults choose vaccination without testing because it is faster and costs less than a blood test in many settings.

Adults who are pregnant, have weakened immune systems, or have a severe allergy to gelatin or neomycin should discuss MMR vaccination with their doctor before receiving it. For most other adults, the vaccine carries minimal risk and significant benefit.

What to do if you think you have measles

If you develop fever, cough, and a spreading rash, contact your doctor before going to the office or emergency room. Tell them you think you might have measles so they can take precautions to prevent spreading it to other patients. Your doctor can often diagnose measles based on symptoms and the rash pattern, though a blood test or throat swab can confirm it.

There is no specific treatment for measles — your body fights the virus on its own. Treatment focuses on managing symptoms: rest, fluids, fever reduction, and monitoring for complications. If you develop severe cough, difficulty breathing, or confusion, seek emergency care. Most adults recover at home, but some need hospitalization if complications develop.

While you are sick, stay home and away from others for at least four days after the rash appears. This protects people who cannot be vaccinated, including infants too young for the vaccine and people with certain immune conditions.

Measles outbreaks and adult risk in your community

Measles outbreaks happen when vaccination rates in a community drop below a certain threshold. The virus needs about 95 percent of the population to be immune to stop spreading — this is called herd immunity. When vaccination rates fall below that, measles can spread rapidly, even among adults who thought they were protected or who had only one vaccine dose.

Outbreaks often start in communities with lower vaccination rates and can spread to nearby areas through travel. Healthcare workers, teachers, and people who travel internationally face higher exposure risk. If an outbreak is happening in your area, checking your immunity status and getting vaccinated if needed becomes more urgent.

Frequently Asked Questions

Can I get measles twice?

No. Once you recover from measles, your body produces antibodies that protect you for life. If you were vaccinated and it worked, you have the same lifelong protection. The only way to get measles twice is if the first infection did not trigger immunity, which is extremely rare.

Is the MMR vaccine safe for adults?

Yes. The MMR vaccine has been used for decades and is safe for most adults. Common side effects are mild: arm soreness, low fever, or a brief rash. Serious side effects are very rare. Pregnant women should wait until after delivery to get vaccinated, and people with certain immune conditions should discuss it with their doctor first.

How do I know if I am immune to measles?

A blood test can show whether you have measles antibodies. Your doctor can order this test. Alternatively, if you have records showing two MMR doses or one dose plus a documented measles infection, you are considered immune. If you have no records and are unsure, vaccination is simpler and safer than testing.

What if I was vaccinated as a child but do not have proof?

You can get a blood test to check immunity, or you can get revaccinated. Revaccination is safe even if you were already immune, and it is often faster and cheaper than testing. Many adults choose this route when records are lost.

Can adults who are vaccinated still catch measles?

Fully vaccinated adults (two doses) have about 97 percent protection and rarely catch measles. Those with one dose have about 93 percent protection and are more vulnerable. Unvaccinated adults have no protection. In large outbreaks, even some vaccinated people can get infected, but their illness is usually milder than in unvaccinated people.