Measles Journey Points Up Risk to Unvaccinated Kids
Minnesota outbreak began with a toddler traveling overseas, study says
By Amy Norton
MONDAY, June 9, 2014 (HealthDay News) -- A measles outbreak in Minnesota offers a case study of how the disease is transmitted in the United States today: An unvaccinated person travels abroad, brings measles back and infects vulnerable people -- including children who are unprotected because their parents chose not to vaccinate them.
That's the conclusion of a report published online June 9 in Pediatrics that details the 2011 outbreak that sickened 19 children and two adults in the state.
It began when an unvaccinated 2-year-old was taken to Kenya, where he contracted the measles virus. After returning to the United States, the child developed a fever, cough and vomiting. However, before measles was diagnosed, he passed the virus on to three children in a drop-in child care center and another household member. Contacts then multiplied, with more than 3,000 people eventually exposed.
Nine of the children ultimately infected were old enough to have received the measles-mumps-rubella (MMR) vaccine but had not.
In most of those cases, the child's parents feared the MMR vaccine could cause autism, according to researchers at the Minnesota Department of Health.
That idea -- first raised in 1998, by a British doctor named Andrew Wakefield -- has been discredited, said Pam Gahr, an epidemiologist who led the new research.
"But I think that as long as autism remains unexplained, the idea [that the MMR is a cause] will persist," Gahr said.
In the Minnesota outbreak, the child infected in Kenya was of Somali descent, as were most of the children whose parents had declined the MMR vaccine because of safety fears.
And that's consistent, Gahr said, with a striking decline in MMR acceptance among Minnesota's relatively large Somali population. In 2004, the number of Somali children in the state who were on schedule with their MMR topped 90 percent.
"By 2010, that was down to just 54 percent," Gahr said.
From what the health department learned in parent interviews, the decline seemed to stem from misinformation about an MMR-autism link.
Despite the unique circumstances of the Minnesota outbreak, though, measles can happen anywhere people are unvaccinated, said Dr. Andrew Pavia, chief of pediatric infectious diseases at the University of Utah in Salt Lake City.