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CDC Issues Measles Advisory

Multistate outbreak linked to Disney theme parks in California

The Centers for Disease Control and Prevention (CDC) and state health departments are investigating a multistate outbreak of measles associated with travel to Disneyland Resort Theme Parks (which includes Disneyland and Disney California Adventure). The CDC has issued a health advisory to notify public health departments and health care facilities about this outbreak and to provide guidance to health care providers.

Measles begins with a prodrome of fever, cough, coryza, and conjunctivitis lasting 2 to 4 days before the onset of rash. The disease can cause severe health complications, including pneumonia, encephalitis, and death. The measles virus is transmitted by contact with an infected person through 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.

According to the CDC, the U.S. is experiencing a multistate measles outbreak that started in California in December 2014 and has spread to six additional states and Mexico. The initial confirmed patients had visited Disneyland Resort Theme Parks in Orange County, California, from December 17 through December 20, 2014.

From December 28, 2014, through January 21, 2015, 51 confirmed cases of measles linked to this outbreak have been reported to the CDC –– 42 from California and nine from six other states (three in Utah, two in Washington, and one each in Oregon, Colorado, Nebraska, and Arizona). In addition to the U.S. cases, one case was reported from Mexico in an unvaccinated child who visited Disneyland Resort Theme Parks on December 17 and December 20, 2014.

At this time, no source case for the outbreak has been identified, the CDC says, but it is likely that one or more travelers who were infected with measles overseas visited one or both of the Disney parks in December during their infectious period.

For cases in which age was reported, the ages of the patients range from 10 months to 57 years (median, 16.5 years). To date, eight (15%) patients have been hospitalized. Of the 52 outbreak-associated cases, 28 (55%) were unvaccinated; 17 (31%) had an unknown vaccination status; and six (12%) were vaccinated. Of the six vaccinated cases, two had received one dose of vaccine and four had received two or more doses. Among the 28 unvaccinated cases, five were too young for vaccination.

Measles genotype information was available from nine cases; all were genotype B3, and all sequences linked to the current outbreak were identical. The sequences were also identical to the genotype B3 virus that caused a large outbreak in the Philippines in 2014. During the last 6 months, identical genotype B3 viruses were also detected in at least 14 countries and in at least six U.S. states, not including those linked to the current outbreak.

In the CDC’s announcement, health care providers are advised to ensure that all patients are up to date on the measles-mumps-rubella (MMR) vaccine and other vaccines. Children 1 through 12 years of age may receive the measles-mumps-rubella-varicella (MMRV) vaccine.

For people who travel abroad, the CDC recommends that all U.S. residents older than 6 months be protected from measles and receive the MMR vaccine, if needed, prior to departure. Infants 6 through 11 months old should receive one dose of the MMR vaccine before departure. (Infants who receive a dose of MMR vaccine before their first birthday should receive two more doses of MMR vaccine, the first of which should be administered when the child is 12 through 15 months of age and the second at least 28 days later.) Children 12 months of age or older should have documentation of two doses of MMR vaccine (separated by at least 28 days). Teenagers and adults without evidence of measles immunity should have documentation of two appropriately spaced doses of MMR vaccine.

Health care providers should also consider measles as a diagnosis in any person with a febrile rash illness and clinically compatible symptoms (i.e., cough, coryza, and/or conjunctivitis) who has recently traveled abroad or who has had contact with someone with a febrile rash illness. Immunocompromised patients may not exhibit rash or may exhibit an atypical rash. The incubation period for measles from exposure to fever is usually about 10 days (range, 7 to 12 days), and the period from exposure to rash onset is usually 14 days (range, 7 to 21 days).

In addition, clinicians should:

  • Isolate suspected measles patients and immediately report cases to local health departments to ensure a prompt public health response
  • Obtain specimens for testing, including viral specimens for confirmation and genotyping
  • Contact the local health department for assistance with submitting specimens for testing

Source: CDC; February 23, 2015.

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