As an infectious disease fellow years ago, I was called to the hospital in the middle of the night for a possible case of measles.

I reviewed the clinical basics, as I was not quite sure what to expect, not previously having seen a case of measles. The emergency room staff had promptly isolated the patient in a negative pressure room. I masked up and went in to see the patient, a teenager from another country who was visiting with a school group.

He had every stigmata of measles: a rash which had started on his face and spread down his body, fever, conjunctivitis, coryza, and a cough (the “3 C’s”), and most amazingly (to me, anyway), Koplik spots. At this time, in the 1990s, I had seen many abnormalities in the oral cavity, most commonly oral thrush and oral hairy leukoplakia in HIV/AIDS patients. The Koplik spots were distinct and matched exactly with what I had read: small grains of gray-colored sand, or salt, surrounded by an erythematous base on the buccal mucosa. In that instant, I knew, as probably the nurses already knew, that indeed this patient had measles.

We immediately called the local health department, who provided expert guidance and next steps. My attending came in and saw the patient. Before daybreak, the patient and his group were on their way home (by private car), and a local measles outbreak was averted.

So, why is this relevant today? We are in the midst of a very unusual situation in the U.S. this year, unfortunately. We have a high number of measles cases, more than 1000 as of late-May 2025, reported in 31 states, and three measles-associated deaths. Two of these deaths were in children, representing the first pediatric measles deaths in the U.S. in 22 years. In addition, many falsehoods about measles and the measles-mumps-rubella (MMR) vaccine have been circulating. This makes for a tragic combination.

MMR vaccination rates in kindergartners have been dropping, and more precipitously so since the COVID-19 pandemic. A vaccination rate of 95 percent is required to provide herd immunity and prevent measles spread. In pockets around the country, rates have dropped below this level. Measles is one of the most contagious respiratory diseases, infecting 9 out of 10 vulnerable people who are exposed. And it lingers in the air. Vulnerable persons may be exposed if they enter the same room where a patient with measles had been two hours earlier.

Why is all of this a big deal? Measles can cause serious complications, including death in approximately 1 to 3 per 1000 cases. Prior to the availability of the vaccine in 1963, three to four million cases of measles occurred yearly in the U.S., resulting in 48,000 hospitalizations, 1000 cases of chronic disability, and 400-500 deaths. An improved vaccine became available in 1968 and remains in use today. Measles rates in the U.S. plummeted, and measles was declared eliminated in the U.S. in 2000.

The only way to prevent measles is vaccination. Two doses of the MMR vaccine are 97 percent effective at preventing measles and confer lifelong immunity. The MMR vaccine has been given to millions of children worldwide and has been estimated to have saved 60 million lives across the globe since 2000. Since it is a live attenuated vaccine, it should not be given to patients with compromised immune systems, nor pregnant women. It does not “kill people every year” and does not cause blindness, deafness, nor autism. The vaccine may cause a transient rash or fever, and it may also induce a febrile seizure (~1 in 3,000 doses, with an increased risk in individuals with a history of seizures or a family history).

Steroids, cod liver oil, and antibiotics do not prevent nor treat measles. Two doses of vitamin A are recommended after a measles diagnosis has been made, based on data showing benefit in children with underlying vitamin A deficiency. Sadly, reports have surfaced of children presenting with vitamin A toxicity, clearly a result of concerned but misguided parents.

What are some other complications of measles? In medical school, we all learned about the dreaded subacute sclerosing panencephalitis (a mouthful to say), a condition which develops 7–10 years after measles, and results in death. This always seemed especially tragic to me, as something particularly devastating that seemingly can come out of nowhere. Pneumonia is the most common reason for hospitalization and death. Diarrhea, otitis media, and deafness may occur. Children may develop acute encephalitis or acute disseminated encephalitis (~1/1000 cases), both of which are associated with residual abnormalities or death. Those most at risk for complications include children < 5 years, adults > 20 years, pregnant women, and people with immunocompromise. In addition, studies have shown that immune suppression may account for increased mortality rates for up to three years following measles.

The benefits of two doses of the MMR vaccine far outweigh the risks of getting measles. This vaccine prevents death and disability. Think about that.

A majority of Americans are convinced of the value of the MMR vaccine. Professional societies, such as the American College of Physicians, amongst many others, are vocal in their support of vaccines and vaccinations.

How can we best help our patients? By being knowledgeable and empathetic. By listening carefully, seeking to understand concerns, and accurately explaining risks and benefits. By vaccinating. And to be on the lookout for measles, like my patient years ago, because we know measles is out there.

Janet A. Jokela, MD, MPH, completed her term as ACP Treasurer at IM 2025. She serves as professor and senior associate dean of engagement at the Carle Illinois College of Medicine, Urbana, IL. She may be reached on BlueSky @drjanetj.bsky.social.

The American College of Physicians is the largest medical specialty organization in the United States, boasting members in over 145 countries worldwide. ACP’s membership encompasses 161,000 internal medicine physicians, related subspecialists, and medical students. Internal medicine physicians are specialists who utilize scientific knowledge and clinical expertise for diagnosing, treating, and providing compassionate care to adults, spanning from those in good health to individuals with complex illnesses. Stay connected with ACP on X @ACPIMPhysicians, Facebook, LinkedIn, and Instagram @acpimphysicians.