By Donna Ross, Ph.D.
Associate Professor, School of Health Sciences
In the early 1950s, measles was a common childhood disease in the United States. However, widespread vaccination eventually brought cases down so dramatically that U.S. health officials declared measles eliminated in 2000.
Unfortunately, new measles outbreaks are now occurring across the country, raising concerns about the health of children and adults who are not protected from this disease.
As of October 22, 2026, there were 4,588 confirmed measles cases in the U.S. according to the Centers for Disease Control and Prevention (CDC). That is TWICE the number of reported measles cases in 2025 (2,289). This increase is troubling because we have an effective vaccine that can prevent most measles infections.
Measles is a highly contagious viral infection. It can cause serious complications, particularly among vulnerable groups such as adolescents, pregnant women and immunocompromised people.
What Is Measles and How Does It Spread?
Measles is a viral respiratory infection caused by a virus. The virus travels through the air whenever an infected person breathes, coughs or sneezes.
You don’t need direct physical contact to catch measles; simply being in the same room is enough. In fact, the virus can remain in the air and stay contagious for up to two hours after an infected person leaves the room.
Measles is especially concerning because people can transmit the virus even before realizing they are sick. A person with measles is generally contagious from four days before the rash appears until four days afterward.
What Are the Early Signs and Symptoms of Measles?
The symptoms of measles almost mimic a cold and start one to two weeks after exposure (although the symptoms can take longer to appear at times). The first warning signs typically include:
- High fever, sometimes exceeding 104 degrees Fahrenheit
- Persistent cough
- Runny nose
- Red, watery eyes
- Fatigue and general discomfort
- Small, white spots inside the mouth (Koplik spots)
Koplik spots may appear two to three days after the initial symptoms begin. These tiny white spots are often found along the inner cheeks and can be an important early indicator of measles.
What Does the Measles Rash Look Like?
The measles rash typically appears three to five days after the first symptoms begin and consists of flat red spots, sometimes with small, raised bumps. Unlike rashes that pop up all over at once, measles tends to follow a set pattern.
The measles rash generally begins on the face, often near the hairline. It then spreads downward to the neck and chest and continues to the arms, abdomen, legs, and feet.
Why Is Measles More Dangerous Than Many People Realize?
Some people assume measles is simply a childhood illness that causes a temporary fever and rash. However, this disease can affect several body systems and lead to serious health complications.
According to the CDC, approximately one in five unvaccinated people in the United States who develop measles require hospitalization. Potential complications include:
- Ear infections
- Diarrhea
- Pneumonia
- Encephalitis (swelling of the brain)
- Pregnancy complications
Some patients develop “immune amnesia,” a condition in which the immune system loses its memory of previous infections. As a result, some people may become more vulnerable to other infections even after recovering from measles.
Who Is Most at Risk for Serious Complications?
People who are not immune to measles can become infected. However, certain populations are more likely to experience severe complications.
For instance, children under 5 years of age are much more likely to develop serious complications. Babies are at the highest risk, simply because they are often too young to get the measles, mumps and rubella (MMR) vaccine.
Women who contract measles during pregnancy face an increased risk of severe illness and complications. Because pregnant women cannot receive the MMR vaccine, getting vaccinated beforehand is critical.
People undergoing certain cancer treatments, organ transplant recipients and people with compromised immune systems often have a hard time fighting off this disease. In addition, many people in these groups cannot safely take the live MMR vaccine.
Why Is the MMR Vaccine So Important?
The MMR vaccine protects against three viral diseases: measles, mumps and rubella. Vaccination is recommended as the best protection against measles and reduces its spread within communities.
The CDC notes that one dose of the MMR vaccine is approximately 93% effective against measles. Two doses are approximately 97% effective against measles.
When Should Children Receive the MMR Vaccine?
The CDC recommends two routine doses of the MMR vaccine for children:
- First dose at 12 to15 months of age
- Second dose 4 to 6 years of age
Children who are traveling internationally or living in an area experiencing a measles outbreak may need additional protection earlier than the routine schedule. For example, infants between 6 and 11 months of age may receive an early MMR dose before international travel or when recommended by public health officials during an outbreak. An early dose given before the first birthday does not replace the two routine doses recommended after 12 months of age.
Do Adults Need the MMR Vaccine?
Many adults received measles vaccinations during their childhood and remain protected. However, some individuals, including healthcare workers, may need additional evaluation. Immunity is presumed for anyone born before 1957 because measles was widespread before vaccination became available.
What Should You Do If You Think You Have Measles?
If you develop symptoms consistent with measles or are exposed to someone with measles, contact your healthcare provider immediately. Call before visiting a medical office, urgent care center or hospital.
Because measles spread through the air, arriving without advance notice could expose other patients and healthcare workers. Providers will explain how you can get a medical evaluation.
If you suspect you have measles:
- Stay home and avoid contact with others.
- Do not attend school, work or public gatherings.
- Avoid contact with infants, pregnant women and people with weakened immune systems.
If you experience severe breathing difficulties, confusion, seizures, or other serious symptoms, get help immediately by contacting your doctor or emergency department.
How Can Families Help Prevent Outbreaks?
Preventing measles begins with knowing your vaccination status and understanding the importance of community protection. Families can take several steps to reduce their risk:
- Keep children’s MMR vaccinations up to date.
- Review vaccination records before international travel.
- Contact a healthcare provider if vaccination records are missing or incomplete.
- Adhere to public health guidance during outbreaks.
Centers for Disease Control and Prevention® and CDC® are registered trademarks of U.S. Department of Health and Human Services.
About the Author
Dr. Donna Ross is an associate professor in the School of Health Sciences at the University, teaching undergraduate and graduate public health courses. She holds a Ph.D. in Public Health from Walden University.
Dr. Ross has a 20-year background in public health. Her research focuses on health disparities, women’s health, public health and healthcare policy. She has oversight for practicum research and won the University’s Excellence in Teaching Award in 2025.
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