Three toddlers living in Hennepin County have contracted measles, state health officials have confirmed.
The Minnesota Department of Health (MDH) is working with county health officials to investigate the three cases, and they are also monitoring other potential cases involving people who have had contact with the toddlers.
In all three cases, the toddlers were unvaccinated, according to a MDH news release.
Health officials are investigating how the children came to be infected and are working with those exposed to them so they can be protected from infection.
Symptoms of measles can include a high fever, cough, runny nose and watery eyes, and a rash that spreads from the head to the rest of the body. It's a serious illness that can lead to hospitalization or even death, MDH said.
Although measles was declared eliminated in the U.S. in 2000, Minnesota still sees a handful of cases every year mostly due to international travel.
That said, there is a risk that cases will rise because immunization rates have been declining in some communities and groups amid skepticism about mandatory vaccinations, as described in this New Republic piece.
Some 79 percent of U.S. measles cases in 2014 affected people who were unvaccinated because of "personal belief exemptions," the health department said, citing Centers for Disease Control figures.
The MDH says the fears about vaccination risks are based on "misinformation."
In 2016, the CDC said there were 70 confirmed cases of measles across 16 states. This was down from 2015 when there were 188 cases.