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Abstract & Commentary
Measles It's Back!
By Stan Deresinski, MD, FACP, FIDSA, Clinical Professor of Medicine, Stanford, Associate Chief of Infectious Diseases, Santa Clara Valley Medical Center, is Editor for Infectious Disease Alert.
Synopsis: Measles remains endemic in much of the world and is surging in Europe, resulting in an increased risk of infection in U.S. residents who travel internationally.
Sources: Centers for Disease Control and Prevention (CDC). Notes from the field: Measles outbreak Hennepin county, Minnesota, February-March 2011. MMWR Morb Mortal Wkly Rep 2011;60:421; Centers for Disease Control and Prevention (CDC). Measles imported by returning U.S. travelers aged 6-23 months, 2001-2011. MMWR Morb Mortal Wkly Rep 2011;60:397-400.
On Feb. 15, 2011, a 30-month-old U.S.-born child of Somali descent developed a skin rash 14 days after returning from a trip to Kenya and 1 day after visiting a child care center. Subsequent evaluation demonstrated the child to have measles caused by a genotype B3 strain known to be endemic in sub-Saharan Africa. Epidemiological investigation identified a total of 13 epidemiologically linked cases in Hennepin County, MN, including three contacts at the child care center and one household contact, as well as secondary and tertiary exposures in congregate living facilities for homeless individuals, an emergency department, and households. Those affected were children 4 months to 4 years of age as well as 1 adult; 8 were hospitalized. Five of the children were too young to have been vaccinated, and 6, all of whom were of Somali descent, had not been vaccinated because of parental concern about vaccine safety.
A total of 29 measles cases were reported to CDC in the first 2 months of 2011 and 28 of these were import-associated (i.e., either imported or the ultimate result of contact with an imported case). Of the latter, 16 were directly imported and 13 of these occurred in U.S. residents. The occurrence of 13 such cases in 2 months can be compared to the total of 159 imported cases in U.S. residents reported in the 10 years ending in 2010.
Seven of the 13 imported cases in U.S. residents were in children 6-23 months of age. While 4 of the 7 were hospitalized, all recovered. The diagnosis was delayed in 3 of the 7, including one child who had been seen by a pediatrician three times before the diagnosis was finally made during an emergency department examination. None of the 7 had been vaccinated as was true for 44 of the 47 with imported measles during 2001-2010. In one instance, the parents had been advised by their child's pediatrician that pre-travel vaccination was unnecessary (it is not stated if this was the same pediatrician who failed to diagnose measles during three patient visits).
Measles was declared to have been eliminated as an endemic disease from the United States in 2000 and from all the Americas shortly thereafter. This remarkable public health advance has not been achieved by most of the rest of the world, including regions with advanced economies. The World Health Organization (WHO) European region was the source of 39% of measles imports into the United States during 2005-2008. In September 2010, the 53 member states of the WHO European Region adopted a resolution to renew their commitment to the elimination of measles and rubella and the prevention of congenital rubella syndrome by 2015.1 Unfortunately, rather than elimination of this infection, Europe is currently experiencing a resurgence of measles cases. As of April 18, there have been more than 6,500 cases of measles reported in 33 countries of Europe in 2011.2 The largest number of cases, 4,937, was reported in France; this can be compared to only 5,090 reported in all of 2010. At least some of this increased activity results from the introduction of the G3 measles strain, which is generally found in southeast Asia and had not been detected in Europe since 2006.3
An important factor in the resurgence of measles is the increasing opposition of parents to childhood immunizations, often generated by anti-vaccination organizations. An internet search on the word "vaccination" is reported to be more likely to produce a list of anti-vaccination than of pro-vaccination sites4; 25 of the former sites were recently analyzed.5 This problem appears to be growing, despite factors such as the recent discrediting of the source behind the spurious link between vaccination and autism.
It is important that the anti-vaccination organizations be continually confronted and the focus remain on facts rather than fear. Within the United States, it is important that attention also be focused on measles associated with international travel. U.S. residents traveling abroad should be fully vaccinated. While children ordinarily receive their first dose of MMR or MMRV at 12 months of age, MMR should be administered to children as young as 6 months who are traveling internationally.6 Finally, clinicians must remain alert to the presence of this infection and some may require a refresher on its manifestations.