Measles was declared eliminated from the United States in 2000, meaning that there was no sustained transmission. Yet outbreaks of measles in the United States have continued to occur, with the most recent reported in 2024. According to the Centers for Disease Control and Prevention (CDC), 131 cases of measles in 21 jurisdictions have been reported this year alone. Eight outbreaks—defined as three or more related cases—have occurred. The majority of these cases impact children under 5 years old, and 81% were not vaccinated against the virus. Larger outbreaks are occurring in the UK, parts of Europe, and throughout the world.
What is measles?
Measles is a serious illness that can cause a variety of complications. It is an airborne and extremely infectious disease that can spread readily to unvaccinated individuals and children who are too young to be vaccinated. The virus causes fever and rash that begins on the face, behind the ears, and spreads down to the chest, back, and feet. Infection occurs in stages. No symptoms occur for 10 to 14 days after exposure, followed by fever, often with cough, runny nose and conjunctivitis. After three to four more days, the rash appears.
Symptoms can include:
- Fever
- Cough
- Runny nose
- Inflamed eyes (conjunctivitis)
- Sensitivity to light
- Sore throat
- Koplik spots, tiny white spots with bluish-white centers that form in the mouth
- Headache
What have we learned about the virus?
Measles was first reported in North America in 1765. It became a nationally notifiable disease in the U.S. in 1912, which allowed it to be tracked. It was responsible for sickening about three to four million people—mostly children—and killing about 6,000 people each year until the vaccine was developed in 1963. The vaccine worked so well in the prevention and spread of measles—97% effective with two doses—that in 2000, measles was declared eliminated in the U.S.
"Vaccines protect our children against these dangerous and sometimes deadly diseases," says Andrew Pavia, MD, chief of the Division of Pediatric Infectious Diseases at the Spencer Fox Eccles School of Medicine at the University of Utah. "As parents, we want more than anything to protect our children."
Yet, while a vaccine for measles has been available since 1963, resistance has always existed. Following the COVID-19 pandemic, vaccine hesitancy increased, fueled in part by misinformation and political tensions. Vaccination rates have since fallen throughout the country, and many areas, including Utah, are now below the 95% vaccination threshold that generally prevents the spread of measles. That has opened the door for increasing measles cases in the U.S. and made our region vulnerable.
Vaccine Hesitancy
In the U.S., children entering school are required to get a number of vaccinations, including the MMR, which protects against measles, mumps, and rubella.
"These requirements are because of the risk not just to your child but also to other children in school, especially those who cannot be vaccinated or don't respond to vaccines," Pavia says. However, there are some exemptions for these vaccines. "Children who cannot safely be vaccinated for medical reasons are granted exemptions in all 50 states,” Pavia says. “Most states offer exemptions for religious reasons and some for philosophical exemptions.”
Many factors have contributed to delayed vaccination of children. Some parents have been concerned that children receive too many vaccines. Others have been influenced by false information that exaggerates vaccine risks. Misinformation and intentional spread of disinformation have only increased with the rise of social media. Some parents are simply overwhelmed by multiple conflicting voices and don’t know what to believe.
Careful studies have not shown any harmful impacts from the number of vaccines that children receive. "It is understandable to ask if getting several vaccines at the same time is 'too many challenges,'" Pavia acknowledges. "However, children are exposed to hundreds of new proteins during birth, and every time they have a cold, put a toy in their mouth, or are exposed to dirt, their immune systems are designed to deal with this. The number of new proteins they are exposed to even when getting multiple vaccines is a fraction of what they are exposed to naturally."
"All of the research to date suggests that getting vaccines together is safe, and it is more humane than spreading out the number of injections."
Pavia says he understands why parents may have questions about vaccines, especially at a time when they are in the headlines. "Part of the problem is that the media likes to find a story with conflict, and they often look for people who oppose vaccines to provide a counterpoint, regardless of whether they are knowledgeable or credible," he says. "This gives a false impression that there is a lot of doubt or controversy when, in fact, very little exists."
Pavia also says that while the public at large is exposed to the debate, very few are actually exposed to the reality of infectious disease. "Most parents with young children are now too young to remember vaccine-preventable diseases, and so they are no longer scared of diseases like measles, whooping cough, or meningitis," he says. "As a young infectious disease doctor, I knew these diseases well and saw the devastating effect on otherwise healthy children. When my children were younger, I could not wait to get them their vaccines."
Parenting is full of hard decisions. Whether or not to protect them from disease shouldn't be one of them. "Vaccines are the one of the best things we can do to protect them,” Pavia says. “It is simply a fact."