School absenteeism is a primary indicator.
Influenza-like illnesses reported in Minnesota schools in mid-December have surpassed the four previous flu seasons for the same week, data from the Minnesota Department of Health shows.
There were 60 Minnesota schools that reported new school outbreaks during the week ending in Dec. 14. Of the 123 reported this flu season to-date, four of those schools included St. Cloud elementary schools, St. Cloud Area School District lead nurse Jessica Vos said.
Schools are required to report an outbreak when the number of students absent with influenza-like illness reaches 5% of total enrollment, or if three or more students with influenza-like illness are absent from the same elementary classroom, according to the Minnesota Department of Health.
This is based on symptoms reported when parents call into the school as well as students sent home with influenza-like symptoms, Vos said.
Two of the St. Cloud elementary schools met both criteria, while the other two met one criterion. Vos did not disclose which elementary schools had reported outbreaks to the state.
However, this is not atypical for flu season, Vos said.
"At some point, most schools do end up having to report in," she said.
What is different about this year is the strain.
"There are more Influenza B cases popping up first rather than Influenza A," Vos said.
Most influenza-like activity in the U.S. this season is being caused by an Influenza B strain called Victoria, which is unusual for this time of year, the Centers for Disease Control and Prevention reports.
Centracare pediatrician Andrew Maloney said their testing largely determines whether the virus tested is Influenza A or B. Locally, he said Influenza B is very predominant, with very little Influenza A.
Typically, Influenza B is a little further from the limelight — but, then again, "typical" isn't really a thing when it comes to flu season, he said.
"That's also typical that there's going to be some years that are off a bit," he said.
The 2019-20 flu vaccines contain either two Influenza A and one or two Influenza B viruses, according to the CDC. Both contain a strain in the B Victoria lineage.
Central Minnesota had the second-highest number of influenza hospitalizations this flu season as of Dec. 14 with 34, or 13% of the total hospitalizations from influenza statewide. The metro region led, with 192 hospitalizations (73% of the total statewide).
Maloney said more people have come in to the walk-in clinic earlier this year with influenza. This is consistent with data from the Department of Health, which shows people visiting outpatient clinics with influenza-like illnesses above the trend line for this time of year compared to the same time during the last four flu seasons.
There have been six influenza deaths this season in Minnesota, but none in children under 18, the Minnesota Department of Health reports in preliminary data.
Maloney recommended people get vaccinated against the flu, isolate themselves from others who are sick and wash their hands frequently.
If you do have flu symptoms, Maloney suggested going in right away rather than wait to see if symptoms worsen.
"That's really different than a lot of other diseases," he said.
The antiviral medication Tamiflu tends to work best within a 48-hour window, and starting the medication early could help significantly with the symptoms, he said.
HOW DOES MINNESOTA COMPARE?
Most surrounding states are not being hit as hard, maps from the CDC show, though several southern states have higher influenza-like illness activity.
Minnesota's influenza-like illness activity level is deemed "moderate," as is North Dakota's, while Wisconsin's activity is low and both Iowa and South Dakota's is minimal, the lowest indicator.
Iowa's most recent flu statistics come from the week ending Dec. 7, which showed just four schools reporting an outbreak. However, Iowa's threshold is twice as high: reports are made when the number of students absent with illnesses reaches or exceeds 10% of total student enrollment.
North Dakota tracks students out ill at select schools. According to data from the week ending Dec. 14, over 14% of students were out sick from school.
Nationwide, mortality surveillance data from the National Center for Health Statistics showed 5.5% of the deaths during the week ending Dec. 7 were caused by pneumonia and influenza. The epidemic threshold is 6.6%.