Measles

If you’ve been hearing about the measles outbreaks and aren’t sure what it means for you, you’re not alone. This guide breaks down everything teens need to know—from how measles spreads to how you can stay safe and protect the people around you. Whether you’re vaccinated or not, understanding the facts is the first step in keeping yourself and your community healthy.

What is measles?

Measles is a very serious and highly contagious viral illness. It is considered an airborne illness, which means it spreads through the air when someone coughs, sneezes, or even breathes. You don’t have to touch anyone to catch it—just being in the same room as someone with measles is enough. The virus can hang in the air for up to 2 hours after an infected person has left.

While many people recover without complications, measles can be dangerous—especially for babies, young children, and people with weak immune systems. It can lead to serious health problems like pneumonia, brain swelling, and even death in rare cases.

What are the symptoms of the measles?

Measles symptoms usually appear about 7–14 days after being exposed to the virus. The illness comes in stages and often starts out looking like a cold. Symptoms can include:

• High fever (can go over 104°F/40°C)
• Cough
• Runny nose
• Red, watery eyes (like pink eye)
• Tiny white spots inside the mouth (called Koplik spots)
• A red rash that starts on the face and spreads down the body

The rash usually shows up a few days after the fever starts. You’re contagious for about 4 days before and 4 days after the rash appears—so you could spread measles before even knowing you’re sick.

How does measles spread?

Measles spreads through the air. That means:

• You can catch it just by breathing the same air as someone who’s infected.
• It can live on surfaces or in the air for up to 2 hours.
• It spreads super easily—up to 9 out of 10 people around someone with measles will get infected if they’re not vaccinated.

This is why measles outbreaks happen fast, especially in places like schools, dorms, or sports events.

Why is there an outbreak in 2025?  

The measles outbreak in the U.S. began in January 2025, with early cases in Texas and later spreading to states like Indiana, Ohio, and Michigan. As of April, there are hundreds of confirmed cases across more than 20 states.

The outbreak is mainly affecting people who haven’t been vaccinated. Some areas have also closed public health clinics due to budget cuts, making it harder for people to get the vaccine in time. Health officials are warning that this could get worse if vaccination rates don’t improve.

How can I stay safe?

You can take steps to protect yourself and others:

• Check your vaccination status: The MMR vaccine (for measles, mumps, and rubella) is your best defense. You need two doses for full protection—usually one around age 1 and the second between ages 4–6.
• Ask your primary care provider or school nurse if you’re up to date on vaccines.
• Avoid crowded indoor spaces if there’s an outbreak near you—especially if you’re not fully vaccinated.
• Wear a mask in high-risk areas or around people who might be sick.
• Wash your hands often, and avoid sharing drinks or food.

Is the vaccine safe?

Yes. The MMR vaccine is very safe and has been used for over 50 years. It protects you from three diseases and is about 97% effective against measles. Some people may have mild side effects like a sore arm, a low fever, or a mild rash. Serious side effects are rare.

Getting vaccinated doesn’t just protect you—it helps protect babies, people with cancer, and others who can’t get vaccinated for medical reasons.

What should I do if I think I have the measles?

If you have symptoms and think you might have been exposed:

• Stay home and avoid other people—don’t go to school, practice, or hang out with friends.
• Call your doctor, urgent care, or clinic first—don’t just show up. They’ll let you know how to come in safely so you don’t expose others.
• Let a trusted adult know, like a parent, guardian, school nurse, or counselor. You don’t have to figure it out alone. 

What happens if I have been exposed but do not have any symptoms?

Even if you feel fine, you should still:

• Tell your doctor or nurse so they can help monitor for symptoms.
• Watch for a fever or rash over the next 2 weeks.
• Avoid public spaces if you’re not vaccinated or unsure about your status.

Sometimes, people exposed to measles can get a special shot (immune globulin) or the vaccine to help prevent symptoms—but timing is important, so don’t wait.

Talk to someone you trust

Dealing with a disease outbreak can feel overwhelming, but you don’t have to handle it alone. Talk to a parent, school nurse, doctor, or counselor if you have questions or need help finding a vaccine. Staying calm, informed, and proactive is the best way to protect yourself and your community.

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Our health guides are developed through a systematic, rigorous process to ensure accuracy, reliability, and trustworthiness. Written and reviewed by experienced healthcare clinicians from Boston Children's Hospital, a Harvard Medical School teaching hospital and consistently ranked as a top hospital by Newsweek and U.S. News & World Report, these guides combine clinical expertise, specialized knowledge, and evidence-based medicine. We also incorporate research and best practices from authoritative sources such as the CDC, NIH, PubMed, top medical journals, and UpToDate.com. Clinical specialists and subject matter experts review and edit each guide, reinforcing our commitment to high-quality, factual, scientifically accurate health information for young people.