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Posted on: June 27, 2023

Health Advisory: Guidance on Measles during the Summer Travel Season

June 27, 2023

Action Requested 

  • Be alert for potential measles cases related to travel – particularly international travel – during the summer season and provide guidance for measles prevention to international travelers.
    • The Centers for Disease Control and Prevention (CDC) recently issued a Health Alert Network (HAN) Health Advisory for clinicians and public health officials regarding measles and summer travel.
    • Measles (rubeola) is extremely contagious; one person infected by measles can infect 9 out of 10 of their unvaccinated close contacts. As of June 8, 2023, CDC has been notified of 16 confirmed U.S. cases of measles across 11 jurisdictions, with 14 (88%) linked to international travel. 
    • Based on current estimates, twice as many Americans are planning to travel internationally in 2023 compared with 2022. Many countries and popular travel destinations, such as London, England, have experienced measles outbreaks in recent years. 
    • The United States has seen an increase in measles cases during the first 5 months of 2023, with 16 reported cases compared with 3 in 2022 during the same period. Most of these cases were among children who had not received measles-mumps-rubella (MMR) vaccine. 
  • Ensure that all patients without other evidence of immunity, especially those planning international travel, are up to date on MMR vaccine and other recommended vaccines before their international travel.
  • CDC recommends that all U.S. residents older than age 6 months who will travel internationally, without evidence of immunity, receive MMR vaccine prior to departure.
    • Infants 6 through 11 months of age should receive one dose of 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 receive two doses of MMR vaccine, separated by at least 28 days.
    • Teenagers and adults without evidence of measles immunity should have documentation of two doses of MMR vaccine separated by at least 28 days.
  • At least one of the following is considered evidence of measles immunity for international travelers: 1) birth before 1957, 2) documented administration of two doses of live measles virus vaccine (MMR, MMRV, or other measles-containing vaccine), or 3) laboratory (serologic) proof of immunity or laboratory confirmation of disease.
  • Consider measles as a diagnosis in anyone with fever (≥101°F or 38.3°C) and a generalized maculopapular rash with cough, coryza, or conjunctivitis who has recently been abroad, especially in countries with ongoing outbreaks (e.g., India, Somalia, and Yemen).
  • Be aware that some patients may develop a mild rash reaction in the three weeks following MMR vaccination, which does not typically require testing or public health intervention.
  • Report any suspected or confirmed measles cases in Snohomish County to the Snohomish County Health Department.


Measles is a highly contagious viral illness that typically begins with a prodrome of fever, cough, coryza (runny nose), and conjunctivitis (pink eye), lasting 2-4 days prior to rash onset. Measles can cause severe health complications, including pneumonia, encephalitis (inflammation of the brain), and death. The virus is transmitted by direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs, or sneezes. Measles virus can remain infectious in the air and on surfaces for up to 2 hours after an infected person leaves an area. Measles is transmitted by contact with an infected person through coughing and sneezing. Infected people are contagious from 4 days before the rash starts through 4 days afterward. The incubation period for measles from exposure to fever is usually about 10 days (range 7 to 12 days), and from exposure to rash onset is usually about 14 days (range 7 to 21 days). Declines in measles vaccination rates globally during the COVID-19 pandemic have increased the risk of larger measles outbreaks worldwide, including in the United States.

Measles outbreaks are occurring in all World Health Organization (WHO) regions. Large and disruptive outbreaks (≥20 reported measles cases per million population during a 12-month period) have been reported in the European, African, Eastern Mediterranean, Western Pacific, and Southeast Asian regions during 2023. In the United States, measles is commonly associated with unvaccinated U.S. travelers returning from other countries where measles is actively circulating. International visitors and returning U.S. travelers can expose U.S. residents in transit and after arrival, leading to additional cases and the possibility for larger outbreaks.

For more information, see full CDC HAN Alert

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