At least 48 people, nearly all children, have been infected, and 11 youngsters have been hospitalized with pneumonia and other serious complications of measles, according to the state health department, NBC News reported.
More cases are expected, according to health officials.
"What we have now is a community that was really influenced by these anti-vaccine groups. And they've performed a natural experiment: to forgo the measles vaccine based on this propaganda," David Johnson, program manager with the Hennepin County Health Department, told NBC News.
Somali immigrants have been hardest hit in the outbreak.
"We've seen that the vaccine rates in the community that's being affected right now were once about the same or even a little higher than our average. They've dropped to about half of that," Johnson said.
"And unfortunately now we are seeing the result. Measles is spreading rapidly in the community and 11 children are hospitalized. And at the same time there is no evidence of any corresponding drop in autism in the community," he told NBC News.
The only positive aspect of the outbreak is that it shows that anti-vaccine activists are wrong, according to health officials.