Measles cases in the U.S. are spiking early in 2024 with 58 confirmed cases as of March 14 – that’s the same number of cases reported in all of last year.

In 2023, experts at the U.S. Centers for Disease Control and Prevention (CDC) logged a total of 58 cases of measles in the U.S., including at least one case in Colorado confirmed in December.

Measles outbreaks in the U.S. are currently taking place in Arizona, California, Florida, Georgia, Illinois, Indiana, Louisiana, Maryland, Michigan, Minnesota, Missouri, New Jersey, New York City, Ohio, Pennsylvania, Virginia and Washington.

Cases of the measles are on the rise in the U.S. because vaccination rates for various preventable diseases have declined since the start of the COVID-19 pandemic in 2020.

For people who have not been vaccinated, the likelihood of getting measles after an exposure is all but certain, said Dr. Michelle Barron, UCHealth’s senior medical director for Infection Control and Prevention.

“When someone coughs, spits, or sneezes, the virus becomes airborne — suspended in the air. Let’s say you are in line with me at the grocery store, and I have measles, and I am coughing or sneezing. The virus can hang out in the air for up to two hours after that and you can then breathe in the virus,” said Barron.

“If you are not protected by the vaccine, the measles virus then can infect you. The CDC (U.S. Centers for Disease Control and Prevention) estimates that nine of 10 persons that lack protection to measles will develop measles infection if exposed to a close contact,’’ said Barron, who is also a professor of Medicine at the University of Colorado School of Medicine on the Anschutz Medical Campus.

To understand more about measles, we consulted with Barron and other UCHealth medical experts.

Is measles dangerous? Why do public health experts worry so much about measles?

According to CDC experts, measles is dangerous for the following reasons:

• The virus is highly contagious. It can live in the air for up to two hours after an infected person has left an area.
• A person who is sick and contagious with measles may not know they have it. People with measles can be contagious four days before the rash shows up and four days after it’s gone.
• Measles is so contagious that if one person has it, 9 out of 10 unvaccinated or immune people who come in close contact with that person will also become infected.
• There is no treatment for measles. Patients can also get complications including ear infections and in more severe cases, pneumonia, seizures, inflammation of the brain, known as encephalitis and sometimes, death.
• Infants under three months of age cannot get vaccines for measles and other illnesses. People with compromised immune systems, like those who have had transplants, also are at great risk for contracting diseases. Measles is extremely dangerous to vulnerable people including, babies, elderly and sick people.

What if you haven’t been vaccinated for measles? Are you likely to get it?

Yes. People who haven’t had the MMR vaccine (stands for measles, mumps, rubella vaccine) are highly likely to get measles if they are exposed to someone with a confirmed case.

The MMR vaccine given within 72 hours after exposure (but before symptoms are present) can prevent infection.

What happens if you get measles? How sick can you get?

Measles can cause scary complications, such as seizures, brain damage, ear infections, pneumonia and death.

Vaccination is highly effective against measles, and people who have previously been vaccinated with the MMR vaccine do not need to receive the vaccine again after exposure to measles. Coloradans can check their/their child’s vaccine status through an online database.

Measles is spread through the air and can remain in the air for up to two hours.

What are the signs and symptoms of measles?

The typical onset of symptoms typically takes place 7 to 14 days after exposure. But it may take up to 21 days for an infected person to get sick. A person with measles is contagious for four days before and four days after the rash appears. Signs and symptoms include:

• Fever, cough, runny nose, and red, watery eyes.
• The appearance of rash at the hairline, spreading downward over the body, usually beginning 2-4 days after other symptoms.

If exposed to the virus, how long does it take before signs and symptoms of measles appear?

 Seven to 21 days.

What are the symptoms of measles?

 Most people get a fever, cough, runny nose or red eyes at first. A rash that looks like red bumps appears on the chest and can appear on the arms and back. Characteristic spots can develop in the mouth. These spots often look like white spots in the back of the throat.

Is measles dangerous? Is it deadly?

Yes, measles is dangerous. According to the CDC, some people may suffer from severe complications, such as pneumonia (infection of the lungs) and encephalitis (swelling of the brain). They may need to be hospitalized and could die.

• As many as one out of every 20 children with measles gets pneumonia, the most common cause of death from measles in young children.
• About one child out of every 1,000 who gets measles will develop encephalitis (swelling of the brain) that can lead to convulsions and can leave the child deaf or with intellectual disability.
• For every 1,000 children who get measles, one or two will die from it.
• Measles may cause a pregnant woman to give birth prematurely or have a low-birth-weight baby.

What should you do if you or a family member might have measles?

Stay at home. Don’t go to work, school or daycare. Call your doctor or your care provider.

Should patients have one or two MMR shots?

People who were born prior to 1957 are considered immune. If you were born between 1957 and 1989, you may have only had one shot. You should ask your doctor to either perform a blood test that determines whether your body is protected from the measles virus and whether you need another shot – a booster shot, or simply opt to have an MMR shot without the blood test. If you were born in 1989 or after, you probably have had two shots, but it’s a good idea to verify this.

What if a patient was born after 1989 and has had only one shot?

See your doctor. Your doctor can perform a blood test to check to see if you need to be protected from the measles virus and whether you need another shot. Or patients can simply opt to have an MMR shot without the blood test. There’s no danger in receiving an additional vaccination.

What if patients don’t know if they’ve had the MMR vaccine?

Your doctor can order a blood test to check to see if you need to be protected from measles.

How long does it take for the vaccination to go into effect, so you’re protected from measles?

About one week.

After receiving the first shot, how long do you need to wait to get the second shot?

Patients need to wait at least 28 days to get a second shot.

I thought we had nearly eradicated measles. Why is this dangerous illness coming back?

Like other vaccine-preventable diseases, illnesses like measles are on the rise because many parents are not vaccinating their children.

Dr. Heather Holmstrom, a family medicine expert at UCHealth Family Medicine Clinic in Boulder, has a very simple message for all of her patients and their children: get vaccinated.

“We eradicated these diseases, and now they’re coming back,” said Holmstrom, who is also an assistant professor of family medicine at the CU School of Medicine.

Boulder is one of the areas in Colorado with poor vaccination rates. It’s also an area with a diverse and relatively wealthy population where many people travel around the world. Measles cases are on the rise around the globe. So, increased travel means it’s more likely that Coloradans can bring dangerous diseases home from abroad. Holmstrom spends considerable time educating parents about the importance of vaccines. She also encounters young adults who weren’t vaccinated as children.

“I encourage all young adults whose parents didn’t vaccinate them to get vaccinated,” Holmstrom said.

She often has to dispel common myths that have long since been disproven. There is no evidence that vaccines cause autism.

Holmstrom and her colleagues have to repeat that message over and over and constantly encourage parents to get their babies and children fully vaccinated.

“Routine childhood immunizations are really important for protecting every individual child as well as our community,” she said. “People ask me if I’ve vaccinated my own children, and I’m always really open with them. My own children have gotten every routine vaccine ever available.”

And, she tells them, “Yours should too.”

Who can I call in Colorado if I’m worried about measles? 

If you are worried that you may have been exposed to measles and you are experiencing symptoms, immediately notify your health care provider by telephone. Explain that you may have had a possible measles exposure and describe your symptoms. Call a medical provider before physically showing up to minimize the chance of exposure to other people. If you do not have a health care provider, call an urgent care center or emergency department. For additional information about measles, call the free helpline CO-HELP at 303-389-1687 (toll-free: 1-877-462-2911).

“Anyone who is experiencing symptoms of measles should stay home unless they need medical treatment,” said Dr. Rachel Herlihy, Colorado State Epidemiologist. “People with signs and symptoms of measles should also not go to child care facilities, school, work, or other public places to avoid exposing others to this very serious and highly contagious disease.”

Where can I get MMR vaccines?

The MMR vaccine is safe and effective at preventing measles (as well as mumps and rubella). Two doses of MMR are approximately 97% effective at preventing measles infection.
CDC experts recommend that children receive a first dose of MMR vaccine at 12 to 15 months of age and a second dose at 4 to 6 years of age. People who receive MMR vaccination according to the U.S. vaccination schedule are usually considered protected for life against measles.

The vaccine is widely available in Colorado at no or low cost. The federal Vaccines for Children program provides vaccines at no cost for children from birth through 18 years who are uninsured, underinsured, on Medicaid or Medicaid eligible, and/or Alaskan Native/American Indian.