A potential obstacle is that autism frequently appears in toddlers at about the same time as they receive the MMR vaccine, leading many parents to believe it can cause the developmental disorder. This has driven a significant number of parents to refuse to vaccinate their children.
Their fears were stoked by a now-discredited 1998 report in the Lancet from Dr. Andrew Wakefield, a U.K. doctor who claimed to have established a link between vaccines and the disorder.
Measles can infect unimmunized adults and children. The same issue of the Morbidity and Mortality Weekly Report included a field report of a measles outbreak involving 13 people in Hennepin County, Minn., in February and March.
Those who became sick ranged from 4 months to 31 years. Investigators traced the cases to a U.S.-born child from a Somali family who developed a rash about two weeks after returning from Kenya. The child, who was 2½ years old, had been dropped off at a child-care center a day before the symptoms began.
Three children from the center subsequently developed measles, as did four people living in two homeless facilities, two emergency room patients and three others. Six of the measles patients, all of Somali descent, weren't vaccinated because of parental concerns about vaccine safety, the report said.
"Importations of measles from other countries still occur, and low vaccination coverage associated with parental concerns regarding the MMR vaccine puts persons and communities at risk for measles," the report authors wrote.