Careers

Influenza Update

November 20, 2025

From Wisconsin Division of Public Health:

Health Care Personnel Exclusion and Return to Work Following an Acute Respiratory Illness

https://www.dhs.wisconsin.gov/dph/memos/communicable-diseases/2025-04-bcd.pdf

Influenza

Influenza activity is currently low and slowly rising in Wisconsin. We are seeing significant levels of rhinovirus and parainfluenza viruses. Rates of influenza-like illnesses (ILI) in Wisconsin outpatients are considered low.

CDC has started reporting influenza data again. Across the U.S. there were 867 (2.0%) influenza detections at clinical laboratories, from the 42,928 specimens collected last week. Of detected influenza viruses at public health laboratories last week, 93.1% were influenza A and 6.9% were influenza B. Among influenza A viruses, 71.7% were H3, 28.3% were H1, and 0% were H5. Of genotyped viruses, 50.8% of AH3 viruses are from subclade K. CDC has reported current match estimates between circulating and vaccine strains for this season (H3: 38%; H1: 100%; B: 69%). The percentage of primary care patients with influenza-like illness (ILI) is at 2.1% and is below baseline. ILI activity is moderate in Puerto Rico, low in Louisiana, and minimal in 49 states; Wisconsin has minimal levels. No pediatric deaths have been reported for the 2025-2026 season to date.  

Global health experts are increasingly worried about influenza AH3, subclade K that emerged in June – four months after the makeup of this year’s flu shots had been decided. The new strain, a version of H3N2, is causing outbreaks in Canada and the U.K., where health officials are warning about the early wave that’s sending people to the hospital.

The use of rapid influenza testing is tenuous at this time based on low levels of circulating virus. RIDT(+) results should be confirmed using RT-PCR. Use of rapid COVID-19 testing is reasonable, and positive results do not need confirmation.

Vaccinate:

Primary Care Snapshot

The most common viral causes of acute respiratory infections in Wisconsin primary care practices are rhinoviruses and parainfluenza viruses. For the week ending November 10, 2025, 2.6% of 6,064 specimens tested across Wisconsin and compiled by the Wisconsin State Laboratory of Hygiene were positive for SARS-CoV-2. The most commonly identified gastopathogens are norovirus and Campylobacter.

Over the past 4 weeks the typical ARI case has been 21.0 years old; 75% of patients have been female. 50% of patients identified a sick contact 1-3 days before illness onset and they typically present to the clinic 4.1 days after illness onset. 71.4% of illnesses are characterized as mild, with 28.6% having moderate symptoms and 0% having severe symptoms.                          

Viruses in CirculationPercent* in statewide laboratory surveillancePercent** in primary care surveillance clinics
Influenza A11.50
Influenza B0.00
Seasonal Coronavirus***0.40
RSV1.00
Parainfluenza10.050
hMPV0.50
Rhino/Enterovirus45.650
Adenovirus3.20
Bocavirus0.00
SARS-CoV27.90

 *estimate based on WSLH statewide data

** estimate based on primary care patients seen at five clinics in Dane County 

*** includes HKU1, NL63, 229E and OC43

SARS-CoV-2

Wisconsin: The 7-day average rate for patients hospitalized for COVID-19 in Wisconsin is 0.5/100,000. This compares to rates for influenza 0.0/100,000 and RSV at 0.1/100,000.

COVID-19 Vaccine: Across Wisconsin, 523,556 individuals (8.8% of the population) have received the updated 2025/2026 COVID-19 vaccine.

COVID-19 Wastewater Surveillance: COVID-19 levels for Wisconsin are very low and slowly increasing.

Please refer to guidance provided by Wisconsin Department of Health Services, available at:

https://www.dhs.wisconsin.gov/covid-19/providers.htm

and by the U.S. Centers for Disease Control and Prevention, available at:

https://www.cdc.gov/coronavirus/2019-ncov/hcp/index.html

* The weekly influenza update is adapted from an email from Jon Temte, MD, PhD; Chair, Wisconsin Council on Immunization Practices; Professor, Department of Family Medicine and Community Health, University of Wisconsin School of Medicine and Public Health.

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