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Measles cases are on the rise globally and here in Illinois the number is increasing as well. Vaccines are 97% effective in preventing this highly contagious disease.  To learn more about this infection and get information on vaccination, go to  Learn how to identify measles and the safe and effective vaccine that can prevent this potentially life-threatening infection for adults and children. 

History of Measles in Illinois

Measles became a nationally notifiable disease in the United States in 1912. There was significant under-reporting of Measles, a nearly universal disease among young children, in the pre-vaccine era.

Measles is an exceptionally contagious disease. Ninety percent of all non-immune people who come in contact with an infected person will also become infected.

Measles can cause ear infections and hearing loss, pneumonia, and swelling of the brain. Children are the most susceptible to severe complications: 1-2 children die for every 1,000 that contract the disease, even if they are under hospital care.

Measles can be serious. Children younger than 5 years of age and adults older than 20 years of age are more likely to suffer from complications. Common complications are ear infections and diarrhea. Serious complications include pneumonia and encephalitis.

That death rate is not high compared to some other diseases—but before the measles vaccine, almost all children contracted measles by their fifteenth year, meaning many cases of severe illness occurred. During the decade before measles vaccine became available, measles caused an estimated 400 –500 deaths, 48,000 were hospitalizations and 1,000 cases of encephalitis (swelling of the brain) per year in the United States.  

In 1968. Dr Maurice Hilleman, a pioneer in vaccine development, produced an improved version of the measles vaccine, which is still used today. Maurice Hilleman earned his doctoral degree at the University of Chicago, and developed 40 vaccines during his career.

Measles vaccination campaigns drastically reduced the spread of measles in the United States. In Illinois (xyz cases, based on data).

This is a montage of health marketing materials seen in this photograph, were used to promote measles vaccination participation in the U.S. during the 1960s. Before the measles vaccine became available in 1963, there were approximately 3- to 4-million cases, and an average of 450 deaths a year in the U.S., with epidemic cycles occurring every 2 to 3 years. More than half the population had measles by the time they were 6 years old, and 90% had the disease by the time they were 15-years of age.
CDC Measles Immunization Promotion Poster (1980)

A change in measles vaccination recommendations in 1989—giving people two doses of the vaccine instead of one — was an important step that helped the United States eliminate the disease (absence of continuous disease transmission for greater than 12 months) in 2000. Although intermittent outbreaks have occurred since then in Illinois (see graphic) and elsewhere in the United States the United States has maintained measles elimination status for almost 20 years.

The 2024 outbreak in northeastern Illinois is the largest outbreak in decades, and underscores the ongoing risk of measles importation and spread, the need for high measles vaccination coverage rates, and the importance of a prompt and appropriate public health response to individual cases and outbreaks.

Measles is preventable, but remains a threat worldwide, and in the United States.