Influenza activity is VERY HIGH and increasing across Wisconsin.
The CDC estimates that there have been at least 29 million illnesses, 370,000 hospitalizations, and 16,000 deaths from flu so far this season. Across the U.S. there were 47,328 (31.6%) influenza detections at clinical laboratories, from the 150,006 specimens collected last week. Of detected influenza viruses at public health laboratories, 96.8% were influenza A and 3.2% were influenza B. Among influenza A viruses, 44.6% were H3, 55.4% were H1, and 0% were H5. CDC has reported current match estimates between circulating and vaccine strains for this season (H3: 51%; H1: 100%; B: 100%). The percentage of primary care patients with influenza-like illness (ILI) has increased to 7.8% and is well above baseline. ILI activity is very high in 35 states, high in 9 states, moderate in 2 states, low in 1 state, and minimal in 2 states; Wisconsin has very high levels. 68 pediatric deaths (influenza A: 62); influenza B: 6) have been reported for the 2024-2025 season to date.
Wisconsin has recorded 3,785 hospitalizations for influenza this season. This is above the level in 2023-2024 (2,155) at this point.
The performance of rapid influenza testing is reasonable because of high levels of circulating virus.
The performance of rapid SARS-CoV-2 testing is moderate because of high levels of circulating virus.
There have been 69 confirmed and 8 probable cases (total = 77) detected in 14 states in 2024/2025. Cases have been linked to dairy cattle (42), poultry (29), other animals (2), and unknown (4). There have been 4 hospitalizations one death due to H5N1. The current public health risk is reported to be low.
From Wisconsin DHS - Bureau of Communicable Diseases
Surveillance and detection of influenza A(H5N1)
There have been recent questions about the recommended testing guidance for influenza A(H5N1). DHS has added additional written guidance on the Avian Influenza A Virus webpage, including possible influenza A testing scenarios and the subsequent recommendations, to help guide and inform clinicians. For more guidance on surveillance and detection of influenza A(H5N1), please visit the DHS Avian Influenza A Virus webpage and view “Testing recommendations.” For additional questions or concerns, please contact the Bureau of Communicable Disease at 608-267-9003.
https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html
Antiviral treatment is recommended as soon as possible for any patient with suspected or confirmed influenza who:
Decisions about starting antivirals for patients with suspected influenza should not wait for laboratory confirmation. Empiric antiviral treatment should be started as soon as possible in the above priority groups. Clinicians can consider early empiric antiviral treatment of non-higher-risk outpatients with suspected influenza based upon clinical judgment if treatment can be initiated within 48 hours of illness onset.
Pertussis is declining, but not absent. The percent-positive rate for specimens submitted for pertussis tests is below 1%
Viruses associated with acute respiratory infections in Wisconsin primary care practices have been dominated by Influenza A and RSV. Influenza detections are increasing, RSV detections are stable, and SARS-CoV-2 are decreasing. For the week ending 2/08/2025, 5.6% of 22,138 specimens tested across Wisconsin by the Wisconsin State Laboratory of Hygiene and clinical labs were positive for SARS-CoV-2. The most commonly identified gastopathogen is norovirus.
Over the past 4 weeks the typical ARI case has been 42.1 years old. 68% of patients have been female. 58% of patients identified a sick contact 1-3 days before illness onset and they typically present to the clinic 6.8 days after illness onset. 42% of illnesses are characterized as mild, with 58% having moderate symptoms and 0% having severe symptoms.
| Viruses in Circulation | Percent* in statewide laboratory surveillance | Percent** in primary care surveillance clinics |
|---|---|---|
| Influenza A | 69.4 | 62 |
| Influenza B | 3.7 | 0 |
| Seasonal Coronavirus*** | 0.8 | 8 |
| RSV | 13.4 | 31 |
| Parainfluenza | 0.1 | 0 |
| hMPV | 0.3 | 0 |
| Rhino/Enterovirus | 1.5 | 0 |
| Adenovirus | 0.4 | 0 |
| Bocavirus | 0.0 | 0 |
| SARS-CoV | 10.5 | 0 |
*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 activity is decreasing across Wisconsin.
The 7-day average for patients hospitalized for COVID-19 in Wisconsin is 237 (decreased).
SARS-CoV-2 detections have declined over the past 1 week.
Across Wisconsin, 952,643 individuals (16.1% of the population) have received the updated 2024/2025 COVID-19 vaccine.
- 9.9% of all deaths during week 6 (February 2 - 8) were due to pneumonia, influenza, or COVID-19, and above the seasonal epidemic threshold.
- Variants: the national proportions of variants for the week ending February 15, 2025, were XEC (37%); LP.8.1 (31%), KP.3.1.1 (9%); MC.10.1 (6%); XEC.4 (4%); and LF.7 (3%). SARS-CoV-2 continues to be a rapidly diversifying virus.
Please refer to guidance provided by Wisconsin Department of Health Services and by the U.S. Centers for Disease Control and Prevention.
* 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.
