The coronavirus might be grabbing headlines, but seasonal influenza is doing the damage in Minnesota right now.
The latest flu surveillance data from the Minnesota Department of Health showed a surge last week in hospitalizations and patients showing up in clinics with flu-like illnesses — and the second flu-related death of a child this season. The uptick comes as an unusual early spread of a B strain of influenza, historically tougher on children, has given way to an A strain of the virus.
“Influenza A is really picking up steam right now,” said Karen Martin, an epidemiologist with the state Health Department.
More than 640 people were hospitalized due to influenza in the first two weeks of February — the highest two-week tally of the season, according to state flu data released Thursday. The share of patients coming into clinics with flu-like symptoms reached 7.3% last week, the second-highest rate of the season.
The surge in cases comes despite initial estimates released Thursday by the U.S. Centers for Disease Control and Prevention that this year’s vaccine has been 45% effective. That is considered average; the effectiveness rate has ranged from 10 to 60% in prior years.
While the flu season so far has been harshest on children — Minnesota already has reported a record 762 outbreaks of flu-like illnesses in schools — the CDC reported that the vaccine has been more effective for that age group.
The effectiveness data suggests the vaccine has cut the number of clinic visits by sick children in half, Martin said.
“It has been a particularly bad year for kids,” she said. “It would have been quite a bit worse if people had not been vaccinated.”
The late-season emergence of A strains of influenza has caused only a slight increase in outbreaks among the most vulnerable adults in long-term care facilities. Martin said the worst seasons in these facilities involved A3 strains, not the A1 strain that is spreading now.
Minnesota has tallied 58 flu-related deaths, including two pediatric deaths, which is below average at this point when compared with prior flu seasons.
Martin said it isn’t too late to get a flu shot, especially given the unpredictability of the current flu season, the first in her experience in which a B strain circulated widely before an A strain.
Last year showed flu can linger, as infections and one death were reported in June 2019.