As measles spreads nationwide, fewer Minnesota kindergartners have ‘herd immunity’

Fewer Minnesota kindergartners are fully vaccinated against measles, new Minnesota Department of Health data shows, falling well short of the 95% “herd immunity” target set by state officials and public health professionals to prevent community transmission.

About 87% of Minnesota’s kindergartners had both doses of the mandated MMR vaccine, which protects against measles, mumps and rubella, this school year, continuing a downward trend.

Minnesota has reported two measles cases so far in 2025, following 70 cases last year — the highest measles case count since an outbreak in 2017.

Nationally, nearly 1,000 cases have been confirmed across 30 states this year, with outbreaks especially concentrated in Texas, where two unvaccinated children have died.

In the 2023-24 school year, Minnesota’s MMR vaccination rate ranked the fourth worst in the country, ahead of Idaho, Alaska and Wisconsin.

Statewide, Minnesota kindergartners haven’t met that 95% herd immunity threshold in at least a decade, but the MMR vaccination rate has also been on a steady decline since the onset of the COVID-19 pandemic in 2020.

The share of students who get a medical exemption — usually meaning they are allergic or immunocompromised in some way — has been a consistent sliver of unvaccinated children.

But the share of students whose parents file a nonmedical exemption, previously called a conscientious objection, has been steadily climbing.

Those 5.7% of kindergartners alone — amounting to about 3,600 children — would mathematically put Minnesota’s kids below herd immunity, but there’s another muddier category: partial vaccination.

“Partially vaccinated” kindergartners include students who have either zero or one dose of the MMR vaccine instead of the required two, but the students do not have a notarized exemption either. It can also mean parents simply haven’t submitted records to the school. The share of kindergartners in this fuzzy category has also risen since 2020, but seems to be evening out.

But Minnesota isn’t a monolith — some regions of the state have seen bigger changes in MMR vaccine uptake than others.

In 2014, more than half of Minnesota’s 87 counties met the herd immunity threshold. That started to taper slightly even before the pandemic, but increased vaccine hesitancy is evident.

This school year, there were only five counties whose kindergartners met the threshold: Pennington, Traverse, Yellow Medicine, Cottonwood and Watonwan.

Central Minnesota counties like Clearwater, Stearns, and Wadena have fallen further behind the target than others.

Wadena County, with Hwy. 10 running through its southwest corner and Menahga in the north, has the lowest vaccination rate in the state — and the highest share of kindergartners with nonmedical exemptions. Of 206 enrolled kindergartners across four school districts this year, more than a quarter have a nonmedical exemption.

Clearwater County’s vaccination rate for its 94 kindergartners is nearly as low, but they don’t have a high share of exemptions — instead, they have the highest share of kids in that “partially vaccinated” category.

Charter schools, which are counted as their own district, have a lower vaccination rate generally than traditional public schools, though both have dropped at about the same rate. In this school year, traditional public school districts had a full vaccination rate slightly higher than the state average at about 87%. Charter schools, by contrast, have about 77% of kindergartners with full MMR vaccination.

Some individual school districts have also experienced steep drops since 2014. Districts like Higher Ground Academy, Menahga, and Stride Academy Charter School in St. Cloud have seen rates fall by more than 30 percentage points.

At Higher Ground Academy, a charter school in St. Paul with nearly 100 kindergartners, only 26 children were fully vaccinated this year, the rest are categorized as partially vaccinated.

In Menahga, the biggest district in Wadena County, more than half of kindergartners have nonmedical exemptions; the same is true for nearly a quarter of the kindergartners in Dassel-Cokato.

Among the 10 districts with the largest declines, four are charter schools. In most cases, the drop is driven by high partial vaccination rates. But at Kaleidoscope Charter School in Otsego, and Menahga and Dassel-Cokato, the decline is due to a high nonmedical exemption rate.

Some school districts and charter schools are seeing significant progress, too.

The Dilworth-Glyndon-Felton district made the largest improvement, with a 19 percentage point increase. Of other districts with big improvements, most were below 80% in 2014 but have since caught up to the statewide rate.

The MMR vaccine requires two doses and is one of five vaccines that is state-mandated for incoming kindergartners to be current on before starting school. The other mandated vaccines protect against diphtheria, tetanus, whooping cough (pertussis), polio, hepatitis B, and chicken pox (varicella).

There are similar requirements for child care centers, early learning centers and older children.

Though vaccination rates for all five have plummeted, MMR has fallen the most for kindergartners.

Search below for your school’s MMR full-vaccination rate and nonmedical exemption rate for kindergartners in the 2024-25 school year.

Data sources: Minnesota Department of Health, Centers for Disease Control and Prevention