Questions & Answers

What causes measles?
Measles is caused by a virus.

How does measles spread?
Measles is spread from person to person through the air by infectious droplets; it is highly contagious.

How long does it take to show signs of measles after being exposed?
It takes an average of 10–12 days from exposure to the first symptom, which is usually fever. The measles rash doesn't usually appear until approximately 14 days after exposure, 2–3 days after the fever begins.

What are the symptoms of measles?
Symptoms include fever, runny nose, cough, loss of appetite, "pink eye," and a rash. The rash usually lasts 5–6 days and begins at the hairline, moves to the face and upper neck, and proceeds down the body.

How serious is measles?
Measles can be a serious disease, with 30% of reported cases experiencing one or more complications. Death from measles occurred in approximately 2 per 1,000 reported cases in the United States from 1985 through 1992. Complications from measles are more common among very young children (younger than five years) and adults (older than 20 years).

What are possible complications from measles?
Diarrhea is the most common complication of measles (occurring in 8% of cases), especially in young children. Ear infections occur in 7% of reported cases. Pneumonia, occurring in 6% of reported cases, accounts for 60% of measles-related deaths. Approximately one out of one thousand cases will develop acute encephalitis, an inflammation of the brain. This serious complication can lead to permanent brain damage.

Measles during pregnancy increases the risk of premature labor, miscarriage, and low-birth-weight infants, although birth defects have not been linked to measles exposure.

Measles can be especially severe in persons with compromised immune systems. Measles is more severe in malnourished children, particularly those with vitamin A deficiency. In developing countries, the case-fatality rate may be as high as 25%.

How is measles diagnosed?
Measles is diagnosed by a combination of the patient's symptoms and by laboratory tests.

Is there a treatment for measles?
There is no specific treatment for measles. People with measles need bed rest, fluids, and control of fever. Patients with complications may need treatment specific to their problem.

How long is a person with measles contagious?
Measles is highly contagious and can be transmitted from four days before the rash becomes visible to four days after the rash appears.

What should be done if someone is exposed to measles?
Notification of the exposure should be communicated to a doctor. If the person has not been vaccinated, measles vaccine may prevent disease if given within 72 hours of exposure. Immune globulin (a blood product containing antibodies to the measles virus) may prevent or lessen the severity of measles if given within six days of exposure.

How common is measles in the United States?
Before the vaccine was licensed in 1963, there were an estimated 3–4 million cases each year. In the years following 1963, the number of measles cases dropped dramatically, with only 1,497 cases in 1983, the lowest annual total reported up to that time.

Beginning in the latter part of the 1980s, the incidence of measles increased due to large outbreaks in many U.S. cities. From 1989 to 1991, 55,622 cases were reported with a total of 123 measles-associated deaths. Half of the cases and deaths were in children younger than five years of age. The most important cause of this epidemic was low vaccination rates among preschool-age children.

Due to extensive vaccination efforts, the number of reported measles cases began a rapid decline during the 1990s. By 2004, only 37 cases were reported—a record low. However, new cases continue to be reported, primarily in populations that have refused vaccination for religious or personal belief reasons. In 2008, CDC received reports of 140 measles cases from 19 states and the District of Columbia—the highest number since 1996. Of the 127 cases in U.S. residents, 120 had not been vaccinated or their vaccination status was unknown. Ninety-nine of these individuals were children whose parents chose not to have them vaccinated. Fifteen of the patients, including four infants, were hospitalized.

In addition, measles is still common in many other countries and can be easily imported or contracted when traveling.

Can someone get measles more than once?
No.
 

Questions and answers about measles vaccine

Technical content reviewed by the Centers for Disease Control and Prevention, December 2010