History of Measles

Francis Home, a Scottish physician, demonstrated in 1757 that measles is caused by an infectious agent in the blood of patients. In 1912, measles became a nationally notifiable disease in the United States, requiring U.S. healthcare providers and laboratories to report all diagnosed cases. In the first decade of reporting, an average of 6,000 measles-related deaths were reported each year.

A vaccine became available in 1963. In the decade before, nearly all children got measles by the time they were 15 years old. It is estimated 3 to 4 million people in the United States were infected each year. Among reported measles cases each year, an estimated:

• 400 to 500 people died
• 48,000 were hospitalized
• 1,000 suffered encephalitis (swelling of the brain)

In 1954, John F. Enders and Dr. Thomas C. Peebles collected blood samples from several ill students during a measles outbreak in Boston, Massachusetts. They wanted to isolate the measles virus in the student's blood and create a measles vaccine. They succeeded in isolating measles in 13-year-old David Edmonston's blood.

In 1963, John Enders and colleagues transformed their Edmonston-B strain of measles virus into a vaccine and licensed it in the United States. In 1968, an improved and even weaker measles vaccine, developed by Maurice Hilleman and colleagues, began to be distributed. This vaccine, called the Edmonston-Enders (formerly "Moraten") strain has been the only measles vaccine used in the United States since 1968.

In 1978, CDC set a goal to eliminate measles from the United States by 1982. Although this goal was not met, widespread use of measles vaccine drastically reduced the disease rates. By 1981, the number of reported measles cases was 80% less compared with the previous year.

However, a 1989 measles outbreaks among vaccinated school-aged children prompted the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP) to recommend a second dose of MMR vaccine for all children. Following widespread implementation of this recommendation and improvements in first-dose MMR vaccine coverage, reported measles cases declined even more.

Current Measles History

Just three months into 2025, the U.S. has already recorded over 378 confirmed measles cases, which is higher than the total number of cases during any single year since 2019.

Measles is a highly contagious viral infection caused by the Rubeola virus. It is the most contagious virus known to humans. It primarily affects children but can also occur in adults. The virus spreads through airborne respiratory droplets when an infected person talks, coughs, or sneezes. Measles isn't just a rash; it can lead to pneumonia and brain swelling. Anyone who is not vaccinated or hasn't previously had the disease is at risk, with 9 out of 10 unvaccinated individuals becoming infected upon contact with the virus.

Symptoms usually begin about 7-14 days after infection but can take up to 21 days after exposure.

Possible measles complications

• Hospitalization: About 1 in 5 unvaccinated people in the U.S. with measles are hospitalized.
• Pneumonia: As many as 1 out of every 20 children with measles gets pneumonia, which is the most common cause of death from measles in young children.
• Encephalitis: About 1 child out of every 1,000 who get measles will develop encephalitis (swelling of the brain) that can lead to convulsions and can leave the child deaf or with intellectual disability.
• Death: Nearly 1 to 3 of every 1,000 children who become infected with measles will die from respiratory and neurologic complications.
• Complications during pregnancy: Measles may cause pregnant women who have not had the MMR vaccine to give birth prematurely or have a low-birth-weight baby.
• It can cause serious health complications, especially in young children and the immunocompromised.