Careers

Influenza Update

December 4, 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 rising in Wisconsin. Levels of rhinovirus and parainfluenza viruses are declining. Rates of influenza-like illnesses (ILI) in Wisconsin outpatients are considered low.

Across the U.S. there were 1,646 (5.0%) influenza detections at clinical laboratories, from the 32,972 specimens collected last week. Of detected influenza viruses at public health laboratories last week, 95.8% were influenza A and 4.2% were influenza B. Among influenza A viruses, 82.3% were H3, 17.7% were H1, and 0% were H5. Of genotyped viruses, 56.9% of AH3 viruses are from subclade K. CDC has reported current match estimates between circulating and vaccine strains for this season (H3: 33%; H1: 100%; B: 69%). The percentage of primary care patients with influenza-like illness (ILI) is at 2.5% and is below baseline. ILI activity is high in Colorado and Louisiana, low in 7 states, and minimal in 41 states; Wisconsin has minimal levels. No pediatric deaths have been reported for the 2025-2026 season to date.

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 24, 2025, 3.3% of 7,110 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 45.9 years old; 50% of patients have been female. 60% of patients identified a sick contact 1-3 days before illness onset and they typically present to the clinic 5.2 days after illness onset. 50% of illnesses are characterized as mild, with 50% having moderate symptoms and 0% having severe symptoms.               

Viruses in CirculationPercent* in statewide laboratory surveillancePercent** in primary care surveillance clinics
Influenza A22.70
Influenza B0.00
Seasonal Coronavirus***1.00
RSV4.60
Parainfluenza7.450
hMPV1.20
Rhino/Enterovirus32.450
Adenovirus1.90
Bocavirus0.00
SARS-CoV28.80

*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 0.8/100,000. This compares to rates for influenza 0.2/100,000 and RSV at 0.1/100,000.

COVID-19 Vaccine: Across Wisconsin, 601,549 individuals (10.1% 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 declining.

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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