- Last Update On : 2015-05-10
Measles was declared eliminated in the United States in 2000, because of widespread immunity achieved by a very effective 2-dose measles vaccine that was introduced in 1963. Measles is still common in many parts of the world including some countries in Europe, Asia, the Pacific, and Africa. Travelers with measles continue to bring the disease into the United States. Measles can spread rapidly when it reaches a community in the U.S. where groups of people are unvaccinated.
The United States experienced several large outbreaks in 2008, mainly in communities with a large number of unvaccinated people. Outbreaks have continued to occur in the ensuing years. A record number of 644 cases involving 27 states was reported to CDC's National Center for Immunization and Respiratory Diseases (NCIRD) in 2014. Nearly half of these cases were linked to travel to the Philippines. From January 1 to February 6, 2015, 121 people have been reported to have measles. Most of these cases have been linked to an outbreak at the DisneyLand amusement park in Orange County, California. The majority of people who got measles were unvaccinated.
Measles is a highly contagious respiratory disease caused by the rubeola virus. It is transmitted from person to person by contact with respiratory droplets that are spread by coughing and sneezing. Infected people are contagious from 4 days before their rash starts through 4 days afterwards. After an infected person leaves a location, the virus remains viable for up to 2 hours on surfaces and in the air. After exposure, almost 90% of susceptible persons develop measles.
The average incubation period for measles is 10 to 12 days from exposure to onset of symptoms and 14 days from exposure to rash (range 7 to 21 days). Measles begins with a prodrome of fever, cough, coryza and conjunctivitis. Koplik’s spots on the buccal mucosa are considered pathognomonic of measles and may precede onset of rash by several days. The characteristic erythematous rash appears 2 to 4 days after prodome onset and spreads from head to trunk. The rash recedes in the same direction.
The Centers for Disease Control (CDC) suggests the diagnosis of measles should be considered in any patient with fever ≥ 101°F (38.3°C) and rash that lasts 3 days or more, along with compatible respiratory symptoms.
Most people who get measles recover completely. Complications are more common in adults, children <5 years and immunocompromised patients. They include pneumonia, ear infections, diarrhea and encephalitis. Approximately 1 in 20 cases develop pneumonia and 1 in 1000 cases develops encephalitis. Subacute sclerosing panencephalitis (SSPE) may occur 7 to 10 years after an acute measles infection.
Measles can be severe and prolonged among immunocompromised persons. Measles illness in pregnancy might be associated with increased rates of spontaneous abortion, premature labor and preterm delivery, and low birthweight infants.
Persons who have documentation of adequate vaccination for measles at age 12 months or later, laboratory evidence of measles IgG antibody, laboratory confirmation of disease, or were born before 1957 have acceptable presumptive evidence of measles immunity.
Testing for suspected measles infection should include rubeola IgM and IgG antibodies. Positive IgG with negative IgM results indicate immunity to infection. Positive IgM results with or without positive measles IgG indicates recent infection. Negative IgM and IgG results usually indicate non-immunity and absence of current infection. However, the sensitivity of measles IgM assays varies and may be diminished during the first 72 hours after rash onset. If IgM is negative and the patient has a generalized rash lasting more than 72 hours, a second serum specimen should be submitted for measles IgM (AAP. Red Book, 2012; p. 491). The specimen requirement for rubeola IgG and IgM is one red top or serum gel tube of blood.
Suspected measles patients should be isolated & reported immediately to local and/or state public health departments.