MINNEAPOLIS — Public health officials in Minnesota say they're keeping a close eye on measles outbreaks in various sections of the U.S., after the Centers for Disease Control issued an alert last week about 23 confirmed cases nationwide since Dec. 1.
Minnesota has not reported any cases so far in 2024 and did not record any cases of measles last year, either. However, Minnesota Department of Health senior epidemiologist Jayne Griffith told KARE 11 in an interview that her agency "maintains heightened awareness" due to the increase in measles elsewhere, such as the outbreak in Philadelphia connected to a hospital and daycare.
"It's very concerning that all of the sudden there are many importations occurring in the U.S. at a similar time period," Griffith said. "We're working with our clinician providers and our partners in local public health to maintain awareness and heightened actions so that we can be on top of any hint of a case in Minnesota."
Measles is a highly contagious disease that at one time infected millions of Americans each year, particularly children. However, the introduction of a vaccine in 1963 largely eradicated measles from public life. It was declared officially eliminated in the U.S. in 2000. In the new millennium, Minnesota has recorded only 146 total cases of measles. In most calendar years, the state usually reports anywhere from zero to two cases, except for a few outliers like 2017 (75 cases) and 2022 (22 cases).
Although measles remains rare, the emergence of cases nationwide in recent weeks has alarmed the University of Minnesota's Dr. Michael Osterholm, a leading national expert on infectious diseases. He's particularly worried because vaccination rates for measles, mumps and rubella (MMR) have dropped nationally since the start of the pandemic.
"People thought very little of measles over recent years and that's all because of vaccination, but now we're seeing great resistance to getting vaccinated," Osterholm said. "My level of concern is very high."
According to state data, the measles vaccination rate in Minnesota decreased from roughly 92.6 percent in 2019-20 to 87.7 percent in 2022-23, far below the 95 percent target that experts say is needed for "herd immunity." That number is also among the lowest in the U.S.
The statewide numbers don't tell the whole story, though. A closer examination of district and school-level data for seventh graders in Minnesota reveals how vaccination rates can vary drastically from community to community. For example, roughly 75 districts reported a 100-percent vaccination rate for MMR in 2022-23, and the majority of districts hit the 95-percent mark or higher. However, in other districts, up to 30 and 40 percent of students were not fully vaccinated for MMR.
"Certain schools, certain daycares, these are the ones that are really ripe for a large outbreak," Osterholm said. "It's really almost block by block, city by city, region by region that we have to analyze this data."
Osterholm praised MDH's response and preparedness for measles, but he said he anticipates the state will eventually see cases in 2024.
"The state is doing everything it can to encourage parents to vaccinate their children," Osterholm said. "The problem is, we're seeing a very rapid increase in kids not vaccinated and that is absolutely a recipe for disaster. It's not a matter of if we're going to have measles outbreaks in Minnesota, it's when, it's where, it's how bad it's going to be. And all of this is preventable."
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