BOSTON — This year’s jump in measles in the United States and Canada was costly and occurred among unvaccinated children and adults, suggested several studies being presented at the 49th Annual Meeting of the Infectious Diseases Society of America here Thursday.
In 2011 to date, 212 people with measles have been reported in the United States, 68 were hospitalized and at least 12 of them had pneumonia, reported the Centers for Disease Control and Prevention. This is the largest number of measles cases since 1996. Rapid public health response efforts prevented measles cases and outbreaks from becoming much larger by isolating cases and vaccinating those who were unvaccinated.
Of those infected, 183 (86%) were unvaccinated or their vaccination status was unknown, and 27 (13%) were less than 1 year old. Most of the imported measles cases occurred among U.S. residents traveling overseas to Western Europe (47%), Africa or Asia, where vaccination rates are significantly lower and measles is an ongoing problem.
An outbreak of measles in spring 2011 in Salt Lake County, Utah, began when an unvaccinated local high school student returned home after traveling in Europe, where he was infected. Rapid response to control the outbreak limited it to nine people in Salt Lake County, yet managing the outbreak cost approximately $300,000 for infection control measures by two local hospitals and the local and state health departments. That cost includes physician and staff time, vaccines, immunoglobulin and blood tests, according to the Utah Department of Health.
When a child or adult with measles goes to school, everyone in the school is exposed, and Utah state law dictates that unvaccinated children and teachers — including those who cannot locate their vaccination records — must stay home for 21 days after the exposure. To contain the outbreak, 12,000 people were contacted about possible exposure and 184 people were quarantined, including 51 students. Costs to the schools associated with these actions — such as the hiring of substitute teachers and state money that is withheld from the schools when kids stay home — were not factored into the study.
“Forest fires start with sparks, but unless there is sufficient dry tinder, they won’t roar out of control,” stated James Hughes, IDSA president. “The same is true of outbreaks. The occasional case is not an issue, but when it occurs in a community where a fair number of people are not vaccinated it can cause serious problems," he said.
Thanks to a successful infant measles, mumps and rubella vaccination program, measles has been declared eliminated in the United States — meaning the illness hasn’t had continuous spread — since 2000. But outbreaks can occur when the infection is imported, typically by unvaccinated Americans who are infected while traveling to Europe or other continents and then return home, or by foreign tourists who are infected and travel to this country.
Before measles vaccination was available in the 1960s, about 3 million to 4 million people were infected with measles in the United States every year — 48,000 were hospitalized, 1,000 were permanently disabled and about 500 died, according to the CDC.