Influenza activity is LOW and declining in Wisconsin.
The CDC estimates that there have been at least 45 million illnesses, 580,000 hospitalizations, and 25,000 deaths from flu so far this season. Across the U.S. there were 6,725 (9.7%) influenza detections at clinical laboratories, from the 69,263 specimens collected last week. Of detected influenza viruses at public health laboratories, 88.6% were influenza A and 11.4% were influenza B. Among influenza A viruses, 44.4% were H3, 55.6% were H1, and 0% were H5. CDC has reported current match estimates between circulating and vaccine strains for this season (H3: 65%; H1: 99%; B: 100%). The percentage of primary care patients with influenza-like illness (ILI) has decreased to 3.2% and is above baseline. ILI activity is high in 2 states, moderate in 10 states, low in 9 states, and minimal in 28 states; Wisconsin has low levels. 168 pediatric deaths (influenza A: 151); influenza B: 17) have been reported for the 2024-2025 season to date.
Wisconsin has recorded 6,741 hospitalizations for influenza this season. This is above the level in 2023-2024 (3,901) at this point.
The performance of rapid influenza testing is lower because of low levels of circulating virus.
The performance of rapid SARS-CoV-2 testing is lower because of low levels of circulating virus.
A death of a three-year-old child, due to influenza A(H5N1) has been reported in Mexico. There have been 70 confirmed and 7 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 and one death due to H5N1. The current public health risk is reported to be low.
A large and growing outbreak of measles is occurring in west Texas and New Mexico. As of April 4, 2025, a total of 607 confirmed measles cases were reported by 22 jurisdictions: Alaska, California, Colorado, Florida, Georgia, Kansas, Kentucky, Maryland, Michigan, Minnesota, New Jersey, New Mexico, New York City, New York State, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Texas, Vermont, and Washington; with 74 (12%) hospitalizations and 3 (0.49%) deaths. Most cases (97%) have been unvaccinated or of unknown vaccination status.
For more information on prevention and treatment-
Viruses associated with acute respiratory infections in Wisconsin primary care practices have been dominated by Influenza A. Influenza, RSV, and SARS-CoV-2 detections are decreasing. For the week ending 3/22/2025, 4.0% of 11,791 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 27.2 years old. 91% of patients have been female. 20% of patients identified a sick contact 1-3 days before illness onset and they typically present to the clinic 4.0 days after illness onset. 14% of illnesses are characterized as mild, with 86% having moderate symptoms and 0% having severe symptoms.
| Viruses in Circulation | Percent* in statewide laboratory surveillance | Percent** in primary care surveillance clinics |
|---|---|---|
| Influenza A | 28.5 | 66 |
| Influenza B | 19.5 | 0 |
| Seasonal Coronavirus*** | 2.9 | 0 |
| RSV | 23.2 | 33 |
| Parainfluenza | 0.9 | 0 |
| hMPV | 2.0 | 0 |
| Rhino/Enterovirus | 4.9 | 0 |
| Adenovirus | 0.8 | 0 |
| Bocavirus | 0.0 | 0 |
| SARS-CoV | 17.3 | 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 104 (stable).
SARS-CoV-2 detections have increased over the past 1 week.
Across Wisconsin, 997,731 individuals (16.9% of the population) have received the updated 2024/2025 COVID-19 vaccine.
- 7.5% of all deaths during week 13 (March 23-29) were due to pneumonia, influenza, or COVID-19, and has dropped below the seasonal epidemic threshold.
- Variants: the national proportions of variants for the week ending March 29, 2025, were LP.8.1 (55%), XEC (21%); MC.10.1 (4%); LF.7 (4%), KP.3.1.1 (3%); and MC.28.1 (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.
