UT Southwestern Q&A: What you need to know about the measles

The measles virus is spread through air droplets when an infected person breathes, talks, coughs, or sneezes. The virus can survive up to two hours in the air or on surfaces. That means the virus can spread even after an infected person has left an area.

People who breathe in infected droplets or come in contact with them on surfaces and then touch their eyes, nose, or mouth can become sick.

An outbreak is defined as three or more related cases of measles. The vast majority of infections during an outbreak involve people who are not vaccinated.

Measles was declared eliminated in 2000 in the U.S. But because of declining vaccination rates, we are seeing an increase in cases across the country. In fact, as of March 20, 2025, the number of measles cases in the United States has already exceeded the annual number of cases in all but three of the past 24 years.

Outbreaks typically start with someone being exposed during international travel and bringing the virus home with them. Measles spreads rapidly in populations that have not been vaccinated.

• Cough
• Runny nose
• Fever of 101 degrees or more that can exceed 104 after a few days
• Red eyes
• Small white spots inside the cheeks near molars
• Red rash

A person typically starts showing symptoms 7 to 10 days after exposure to the virus. The initial symptoms of fever, cough, red eyes, and a runny nose are similar to the flu.

The telltale red rash that is typical of a case of the measles does not appear until about 14 days after exposure and usually four days after symptoms have begun. The rash starts on the head and spreads down the body, including to the palms of the hands and soles of the feet.

A person with measles is contagious starting about four days before the rash appears and remains contagious for about four days after the rash appears.

This is a very contagious virus, and it’s very stable in the environment. If we see a child who has measles in our emergency room, for example, we can’t use that room for two hours because the measles virus remains in the air.

The measles-mumps-rubella (MMR) vaccine is the most effective tool to protect against measles. We have six decades of experience with the measles vaccine. A single dose is 93% effective while two doses are considered 97% effective at preventing measles. I can’t think of many other things in medicine that are actually 97% effective.

You are protected if you had measles at some point in your life. Most people born before 1957 likely were exposed to the virus and are believed to have natural immunity.

If you are not sure whether you are fully vaccinated, consider getting vaccinated now to protect yourself.

Before 1968, one of the measles vaccines contained an inactivated (killed) virus that is not as effective as the one used today that contains a weakened (attenuated) form of the virus. The Centers for Disease Control and Prevention (CDC) recommends a dose of the live attenuated vaccine for anyone vaccinated before 1968 who received either the inactivated vaccine or a measles vaccine of unknown type.

The CDC recommends children receive two doses of the MMR vaccine. Children receive the first dose between 12 and 15 months of age. A second dose is given between 4 and 6 years.

In an area where there is a measles outbreak, infants can get an early dose of the MMR vaccine between 6 and 12 months of age. They would then follow the regular schedule for childhood vaccinations as the pre-12-month doses would not count in the vaccine dosing schedule.

If you are vaccinated, you don’t need to do anything. You are protected. If you are not vaccinated or aren’t sure whether you are, you have a window of about three days to get vaccinated to stave off infection.

Vaccines are not recommended if you are pregnant or immunocompromised. Infants under 6 months old are not eligible for the vaccine. Those who have been exposed and are not eligible for the vaccine may receive IV immunoglobulin (a blood product with measles antibodies) in an effort to prevent infection.

The CDC recommends that adults considered at high risk receive an additional dose of the measles vaccine including:

• Health care workers
• Students and staff at post-high school educational institutions
• People planning to travel internationally
• People working with those who are immunocompromised and cannot get vaccinated

Check with your primary care doctor or pediatrician first. Some commercial pharmacies also offer measles vaccines.

The Texas Department of State Health Services has two programs, Texas Vaccines for Children and Adult Safety Net, to help people who are uninsured or underinsured get vaccinated. Visit the state’s website at www.dshs.texas.gov/measles to locate a vaccine clinic near you.

There is no effective treatment for measles. Symptoms should be managed while the virus runs its course.

Studies done in impoverished countries where malnutrition is prevalent have found that doses of vitamin A can reduce the severity of a measles infection. Those studies have not been done among U.S. children who have a more balanced diet. There is no evidence that vitamin A, cod liver oil, or other therapies will prevent a measles infection.

Measles is a dangerous virus, especially for young children, older adults, and people who have a compromised immune system. Severe cases can result in ear infections, blindness, pneumonia, or encephalitis, a swelling of the brain that could lead to hearing loss and intellectual disabilities.

About one out of 1,000 cases turns fatal.

For those who are pregnant, measles also causes complications, including preterm birth, low birthweight, and severe respiratory illness among infants after birth. The measles virus may also potentially be transmitted to the newborn at birth.

Studies have also shown that the measles virus damages the immune system by wiping out previously acquired immunity to other pathogens and immunity induced by prior vaccinations. For example, if a 7-year-old gets measles, immunity that child had built up to protect against the flu, respiratory syncytial virus (RSV), or other common infections may disappear, making the child more susceptible to these and other illnesses.

If you display any of these symptoms, seek medical care immediately:

• Difficulty breathing or breathing faster than normal
• Signs of dehydration (dry nose and mouth, urinating less than usual)
• Confusion, severe weakness, decreased alertness
• Among young children, watch for a blue color around the mouth, crying without tears, unusually low energy, or severe loss of appetite

Call ahead before visiting your doctor or an emergency clinic so that staff can prepare for your visit and others don’t become exposed.

You should keep them at home, have them avoid contact with others, and manage their symptoms. An infection can last up to 21 days.

If you have questions, contact your health care provider by phone or online first rather than showing up in person, which could expose others.

If your child is having difficulty breathing or shows signs of dehydration, seek medical attention immediately.