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Public Health - Seattle & King County


Measles is one of the most highly contagious diseases, but is preventable through vaccination. The measles virus is spread through coughing and sneezing. Before widespread use of measles vaccines there was an average of half a million measles cases and hundreds of deaths each year in the U.S. Measles is common in many parts of the world, including both industrialized and developing countries. Local cases of measles are often linked to travel or exposure to recent travelers. Worldwide, more than 20 million people are infected each year. Measles is the leading cause of vaccine-preventable death among children in the world.

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Measles in King County

Purpose of surveillance:

  • To facilitate prompt diagnostic testing
  • To identify cases and exposed persons at risk for transmitting measles to others
  • To identify susceptible contacts of cases for post-exposure prophylaxis or preventive treatment
  • To implement disease control measures to prevent transmission

Measles Case Data in King County

Local epidemiology:

In 2013, four measles cases were reported among King County residents. One case was reported in an unimmunized child who had recently been adopted from China. This measles case was one of several among adoptees from the same orphanage (the other adoptees resided in other areas of the U.S). Of the other three measles cases in King County during 2013, two occurred in unimmunized adolescent siblings, one of whom became ill after returning from a trip to Germany and Spain; the sibling was a secondary case. The final case was in an infant who was too young to be vaccinated and became ill after a trip to the Philippines. No other secondary cases were reported.

In recent years, all measles cases in King County have been imported from other countries. In 2010 a child adopted from India was infected with measles before arriving in the US. Over 100 King County residents were identified as at-risk for exposure to measles, though no secondary cases were reported (likely due to high measles vaccine coverage in the population). Also in 2010, a Canadian resident with infectious measles visited popular public venues in Seattle resulting in public notifications regarding the risk for measles exposure, no subsequent cases were identified.

Individual cases in 2007 and 2009 were acquired while traveling in India. In 2004, a cluster of six cases of measles occurred in toddlers adopted from orphanages in China, with one secondary case in a family member visiting from California. In 2001, 12 cases of measles were reported, all linked to an outbreak in Korea.

Each year in Washington state typically fewer than 10 cases of measles are reported.