Mayo measles case brings Minnesota’s total to 21 this year

A pediatric patient at Mayo Clinic was diagnosed with measles, exposing others at the Rochester medical campus to the infectious disease and raising Minnesota’s case count to 21 for the year.

Minnesota has now had its fifth-worst year since at least 1997 for measles, according to an update Tuesday by the state Department of Health. The highly infectious disease is increasing in Minnesota at the same time as the state’s vaccination rate is declining.

The unvaccinated preschooler was diagnosed after likely exposure to the infectious disease during international travel, according to a statement from Olmsted County. The statement didn’t identify the countries the child had visited.

The diagnosis occurred after the child had been around relatives as well as other Mayo patients and workers. A statement from Mayo said the health care provider’s personnel were working with public health officials to notify people who had been exposed.

“We have strict infection prevention protocols and highly trained teams who respond swiftly and effectively to infectious diseases," Mayo said in its statement.

No additional infections related to the case have been identified, according to the Minnesota Department of Health.

The measles virus is one of the most infectious agents on the planet, capable of lingering in the air two hours after infected people have left. The virus famously spread from the surface of the Metrodome during a Special Olympics event in Minneapolis in 1991 and reportedly infected people in the upper deck seating.

Measles had diminished in Minnesota, where only three cases were reported from 2003 through 2009, according to annual state infectious disease summaries. Most cases were among foreign travelers and unvaccinated children brought to the U.S. for adoption.

That trend has changed. Fifteen of Minnesota’s cases this year involved person-to-person transmission within the U.S., along with 57 of the 70 cases reported in 2024.

Minnesota once had one of the best measles vaccination rates of any U.S. state for children entering kindergarten. But that rate has declined from a peak of 94% to 87% at the start of the 2022-23 school year, which was below the national average.

Skepticism over the COVID-19 vaccine, which was created and tested in record time during the pandemic, has sewed broader doubt about pediatric vaccines in general.

President Donald Trump appointed a health secretary this year, Robert F. Kennedy Jr., who has long questioned the safety of the measles vaccine, contradicting studies showing it reasonably safe and effective.