Wisconsin Influenza Activity Widespread and Increasing

January 12, 2018

Wisconsin is seeing a steady increase in influenza cases, but public health officials and the health care provider community are hopeful the flu season here will not be as severe as it is being reported in some other states.

According to a report from Jonathan Temte, MD/PhD, chair of the Wisconsin Council on Immunization Practices, influenza A[H3N2] has been the dominant strain so far in Wisconsin, comprising 95 percent of all tested viruses. As of December 30, 2017, there had been 1,328 influenza-related hospitalizations since September 1, 2017; 68 percent of hospitalizations have been in individuals aged ≥65 years. There have been 157 admissions to ICUs, 54 percent were aged ≥65 years; and there have been 29 cases requiring mechanical ventilation, 48 percent aged ≥65 years. 

The prevalence of influenza-like illness (fever of 100 degrees F or higher and either cough or sore throat) in Wisconsin’s primary care patients is at 3.9 percent and increasing.

The most commonly identified viral cause of Acute Respiratory infections (ARI) in Wisconsin is Influenza A. Over the past four weeks the typical ARI case presenting for primary care has been 34 years old and 54 percent of patients have been female. Sixty-three percent of patients identified a sick contact one to three days before illness onset and typically present to the clinic 4.5 days after illness onset. Twenty-nine percent of illnesses are characterized as mild, with 63 percent having moderate symptoms and 5 percent having severe symptoms.

The Wisconsin Department of Health creates weekly statewide and regional influenza activity reports that clinicians may find valuable as well.

This story originally appeared in the January 12, 2018 edition of WHA Newsletter