Top 10 Medical Stories of 2008: No. 2

In 2008, the United States experienced the largest measles outbreak in more than 10 years, due to pockets of imported or importation-associated disease in unvaccinated individuals.* An August report in the MMWR indicated that more than 80% of these 131 cases were related to 7 outbreaks (≥3 cases). Fifteen individuals, including 4 children younger than 15 months of age, were hospitalized for disease. 

Most important, however, is the fact that a whopping 91% of cases occurred in individuals who had not received vaccination or whose vaccination status was unknown. Among these 112 patients, 85% were eligible to receive vaccination, but 66% had declined because of "philosophical or religious beliefs." In many cases, elected exemptions are based on parents' disproven fears of the risk of autism.

In England, measles was declared endemic this year for the first time since the mid-1990s, because a critical number of parents declined vaccinations for their children. Gibraltar also experienced an unprecedented measles outbreak, which affected 1% of the population. The outbreak was blamed on the poor uptake of measles vaccination and a subsequent shortage of the vaccine.

Those most affected by the deferral of measles vaccination are immunocompromised children and children younger than 12 months of age, who rely on adequate herd immunity. It appears to be a matter of time before a measles outbreak will cause a known, severe complication of the disease, like encephalitis or death, in the United States. Such an event occurred in April in the United Kingdom.

By way of contrast, worldwide deaths due to measles dropped dramatically, according to the World Health Organisation. The plunge in measles-related deaths, from 750,000 in the year 2000 to 197,000 last year, is due to a massive, coordinated vaccination effort, the Measles Initiative. In Africa and countries of the Eastern Mediterranean region specifically, the effort resulted in a fall in measles deaths by approximately 90% during the same time period. The goal of the Measles Initiative—which is led by the American Red Cross, the CDC, the UN Foundation, UNICEF, and WHO—is to reduce the number of measles deaths worldwide by at least 90% by the year 2010.

Because the majority of measles-related deaths no longer occur in Africa, vaccination efforts are now being intensified in other regions—particularly India, where 8.5 million children do not receive their first dose of measles vaccine by 1 year of age. According to a spokesperson for the UN Foundation, the success of the campaign depends on urgently needed funds for the next 2 years.

More details can be found at the following Pathophilia links (and at links through these links):

• And the Air-Travel Risks Just Keep on Comin': This Time, Measles
• Looming Large: The Cost of Not Vaccinating
• Measles Outbreak in DuPage County, IL
• Biggest US Measles Outbreak in 10 Years
• Boo, Boo, Boo: US Measles Cases Increase
• Most US Parents Remain Sane, Vaccinate Children
• Measles Hits Gibraltar, Hard
• Global Measles Initiative a Success, but Funding Needed

* The percentage of US toddlers who received at least 1 dose of MMR vaccine (from 91.5% to 93.0%) has remained stable since 2004. Still nearly 8% of American toddlers did not receive vaccination for the disease in 2007, and geographic clusters of unimmunized children appear to account for this year's record number of cases of the highly contagious disease.

Photo of child with measles rash from the CDC.