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US travellers to the London Olympics are warned about contracting measles

BMJ 2012; 344 doi: http://dx.doi.org/10.1136/bmj.e2357 (Published 27 March 2012) Cite this as: BMJ 2012;344:e2357
  1. Janice Hopkins Tanne
  1. 1New York

A doctor at the Centers for Disease Control and Prevention (CDC) has told US travellers to make sure they are vaccinated against measles if they travel to Poland and Ukraine for soccer matches in early June or to London for the Olympics in July.

“Disease knows no borders. We are concerned about Americans coming back from the Olympics this summer and unknowingly infecting others,” Rebecca Martin, director of the CDC’s global immunisation division, told the newspaper USA Today (“US travelers to Olympics may bring home measles,” www.usatoday.com 19 March, 2012).

Measles was declared eliminated in the US in 2000. Most cases of measles are imported by travellers who have not been vaccinated because of religious or personal reasons or by foreign visitors. In 2011 the number of imported cases increased from an average of about 50 cases to 222 and nearly a third of those infected needed hospital treatment.

England and Wales last year had nearly 1100 cases of measles—many more than the US, which has about five times the population of the UK (62 million v 311 million).

National seropositivity rates are high enough that measles is no longer circulating in the US. However, the CDC is concerned that an imported case might be introduced into a community with immunisation rates lower than the national average and spread.

CDC regularly provides advice to US travellers who are attending large international events such as the Olympics. Specific advice for the London Olympics will be posted on the CDC’s website in the next few months.

Kelly Holton, of the CDC’s travellers’ health branch, said that large gatherings like the Olympics bring together people from all over the world, and travellers might be exposed to a variety of diseases, not just the ones common in the country they are visiting. CDC has posted a “Measles Update” for travellers, which advises all travellers to be vaccinated against measles and gives examples of recent outbreaks, including cases in several countries in Europe.

Before routine vaccinations, measles killed 3000 to 5000 people every year in the US. Between 1999 and 2004, among people aged six to 49, 95.9% were seropositive for measles antibody and nearly all population subgroups had measles seropositivity levels greater than the estimated threshold to sustain measles elimination. (J Inf Dis 2007;196:1459-64).

At present 91.5% of children aged 19 to 35 months have received one or more doses of the measles, mumps, rubella (MMR) vaccine, and among teens aged 13 to 17, 90.5% have received two or more doses of MMR. Children might be exempt from vaccination if their parents have religious or philosophical objections.

CDC recommends that children should receive two doses of the MMR vaccine—the first dose at 12 to 15 months of age and the second dose at 4 to 6 years of age.

For people who will travel internationally, CDC recommends that all US residents older than six months receive MMR vaccine, if needed, before departure. Infants aged six to11 months should receive one dose of MMR vaccine before departure. 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 receive two appropriately spaced doses of MMR vaccine.

Notes

Cite this as: BMJ 2012;344:e2357