Hundreds of child care centers across Minnesota are not following state requirements that parents get their children vaccinated for the measles or provide written exemptions, according to state health data reviewed by the Star Tribune.
The situation provides fertile ground for the highly contagious measles virus to continue to spread as the outbreak, which has sickened 68, continues into its eighth week.
It also is hindering public health officials in their efforts to control the outbreak, because vaccination records at some centers are so poorly maintained that they can't quickly identify which children are most at risk where exposures have occurred.
"It has been fairly challenging to get information from the centers," said Kris Ehresmann, infectious disease director at the Minnesota Health Department.
Half the people sickened in the outbreak have caught measles at day care centers, and many passed it on to other unvaccinated family members.
State law requires all day care centers to enroll only children who have the full set of vaccinations appropriate for their age, except children whose parents provide notarized statements exempting them from the requirement for medical or personal reasons.
But in an annual accounting for 2015 provided by the centers to the Health Department, 223 of 1,400 centers across Minnesota reported that 5 percent or more of enrolled children who were supposed to get the measles vaccine did not get the shot and did not have an exemption.
Altogether, that represents about 1,800 children — nearly 600 more than the number who actually filed a personal exemption.