In health-conscious Minnesota, students generally receive high marks for vaccination compliance. In fact, the state health department reports that last school year more than about 98 percent of all kindergartners had been properly immunized.

That's why it raised some eyebrows this week when schools in Rochester — the home of the Mayo Clinic — kept several dozen students out of class for not providing proof of vaccinations or receiving a waiver. Under state law, students are required to have certain vaccinations to attend school.

The good news on this troubling story is that the number of kids on the list dropped significantly during the past several days due to district efforts. Last week, 183 Rochester students either weren't properly immunized or hadn't turned in the necessary paperwork. As of Wednesday, that number was down to 71.

Still, it is fair to question why that many students and families were out of compliance for that long. Families are supposed to provide immunization proof when school begins in September. It's unclear why noncompliance was allowed for two-thirds of the school year.

In an e-mailed statement, Rochester school officials said the noncompliant students are not concentrated in a particular school, geographic area or age group. They said they have worked "diligently" since January to inform families through letters, e-mails, phone calls, and interpreters. Because the students remained out of compliance (officials say they don't know why) the administration then asked the board to remove them by March 1 as a "last resort.''

In general, Minnesota kids entering kindergarten must be vaccinated against a series of diseases including diphtheria, tetanus, polio, measles, mumps and chickenpox. In seventh grade, students receive the meningococcal vaccine and booster shots. Minnesota is one of 18 states that allow exemptions for medical reasons or "conscientiously held beliefs."

The purpose of the vaccination statute is to help prevent outbreaks of communicable diseases that can spread quickly among groups of children. Protecting public health is a good reason for families to get their children immunized, and for school districts to enforce vaccination rules in a timely manner.