Measles cases rise, childhood vaccination rates drop in Minnesota

MINNESOTA — The number of measles cases in the U.S. is nearly three times higher than last year, including 15 cases in Minnesota, according to data released Friday by the Centers for Disease Control and Prevention.

Three of Minnesota’s 15 cases last week were confirmed in the Twin Cities metro area. Last year, there were zero cases in Minnesota.

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With five months left in the year, 26 states and the District of Columbia have reported 188 cases of measles. About half of them (49 percent, or 93) were severe enough to require hospitalization, mostly in people younger than 5.

Last year, the country saw 58 cases of measles in four outbreaks. This year, there have been 13 outbreaks, the largest of which was traced to a migrant shelter in Chicago in March, where 60 illnesses were linked.

Seven states — Massachusetts, Michigan, Minnesota, New Hampshire, New York, Oregon and Vermont — joined the growing list of states with measles outbreaks in the past month, the CDC said. In Massachusetts, it was the first time in three years that this happened.

According to the CDC, the current increase in cases is due to an increase in vaccine hesitancy since the COVID-19 pandemic, as well as a global increase in measles cases.

About 85 percent of measles cases in the U.S. this year involved people who were unvaccinated or whose vaccination status was unknown, and 10 percent involved people who received only one dose of the measles, mumps, and rubella (MMR) vaccine.

In some American communities, the number of people protected against measles by the vaccine has dropped below the 95 percent needed to prevent a measles outbreak.

In Minnesota, 87.7 percent of kindergartners were up to date on their MMR vaccinations in the 2022-23 school year, according to CDC data. Nationally, 93 percent of kindergartners had received two doses of the MMR vaccine that year, compared with 93 percent in the 2019-20 school year, the data show.

Minnesota law requires all students entering kindergarten to be fully vaccinated against diphtheria, tetanus, pertussis (DTaP), polio, measles, mumps, rubella (MMR), hepatitis B (Hep B), and chickenpox.

Measles was declared eliminated from the United States in 2000, a status threatened by a large measles outbreak in 2019, which resulted in 1,200 cases, primarily associated with outbreaks in Orthodox Jewish communities in New York. The 2024 measles outbreak is the largest since then.

Before the vaccine became available in 1963, between 3 and 4 million people were infected each year, of whom 400 to 500 died.

Measles is highly contagious. A sick person can pass it on to 90 percent of people in close contact if they are not immune, and the virus can remain in the air for up to two hours after an infected person has left.

Common symptoms include high fever, cough, conjunctivitis, runny nose, white patches in the mouth, and a rash that usually starts on the face and spreads to the feet.

Between 1 and 3 out of every 1,000 children infected with measles die from measles complications, including pneumonia and swelling of the brain.