The influenza season of 2017-2018 has been worse than expected, based on lab, clinic and outbreak data from the Minnesota Department of Health. And it isn't done with the state yet.
Clinics in Minnesota have reported for the past two weeks that 5.2 percent of their patients are coming in with flu-like symptoms. Nationally, that rate has climbed well above 7 percent, a rate that experts at the U.S. Centers for Disease Control and Prevention said was last seen during the H1N1 swine flu epidemic of 2009.
The flu has been declared widespread in Minnesota, which is typical. The designation means that lab-confirmed cases have been found in every region of the state. However, the toll of the flu appears worse in the rest of the nation, particularly the south.
In Minnesota, outbreaks of influenza-like illness in schools and nursing homes had started to decline in January, but the numbers ticked back up in the week that ended Feb. 3.
Hospitalizations have continued to decline in the state since a peak in early January, but they are a rough indicator of the severity and lethality of a flu season. And the total to date of 3,839 hospitalizations is the second-highest in the last six flu seasons.
More than one in 10 deaths in Minnesota through the first three weeks of January were attributed to influenza or pneumonia infections, according to the U.S. Centers for Disease Control and Prevention. The surveillance data showed 282 deaths related to these infections in the state in that three-week timeframe. So far, only one pediatric death related to the flu has been reported to the Minnesota Department of Health as of Feb. 3.
Lab testing data shows a classic pattern of A strains of influenza causing the most infections, but B strains gradually emerging later in the season. The emergence of B strains could have contributed to an uptick in school outbreaks from 77 in the week ending Jan. 27 to 102 in the week ending Feb. 3.
Outbreaks in schools are reported whenever flu-like symptoms result in more than 5 percent absenteeism, or more than three elementary school students from the same classroom to be out sick.
