Wisconsin Vaccine Preventable Disease Updates: April 2025

Wisconsin Department of Health Services

Immunization Program

WI VPD updates light

This message is being sent to Tribal health directors, local health officers, local health department staff, local health department nurses, Vaccines for Children providers, Vaccines for Adults providers, Wisconsin vaccinators, and key DHS staff.

April 2025

Wisconsin Vaccine Preventable Disease Updates provides statewide data on select vaccine preventable diseases from the previous month. 

Measles

Wisconsin has had no cases in 2025 as of March 31, 2025. Nationally there are currently 712 cases of measles in 25 jurisdictions, with Texas alone reporting 505 cases. CDC updates their measles case webpage weekly on Fridays. The majority of cases (approximately 70%) are under 20 years of age, 97% are unvaccinated or have an unknown vaccination status, and 11% of cases have been hospitalized, with three deaths reported.  

Low MMR rates in Wisconsin’s children continue to be a significant concern. Do not miss any opportunity to evaluate if children are up-to-date and provide vaccination if medically eligible.   

Moreover, providers are strongly encouraged to assess their pediatric patient populations using reports in the electronic medical record (EMR) or the Wisconsin Immunization Registry (WIR) to determine who is not up to date and conduct outreach to schedule appointments for vaccination.

MMR Resources

Measles Questions and Answers 

MMR Vaccine Does Not Cause Autism- Examine the Evidence 

Pertussis

As of March 31, 2025, Wisconsin has 252 confirmed cases statewide in 2025. Since January 1, 2025, 53 counties have had at least one case. While cases range in age from 1 month to 82 years, one-third (32%) of the cases are in adolescents aged 11–18 years. Fifteen infants have been identified with pertussis, and two have been hospitalized. No deaths have been reported.  

The most recent pertussis case count data can be found on the new pertussis dashboard where users can explore trends and view data at the state, region, and county levels. Please note the data are preliminary and subject to change. 

Pertussis resources

The Communicable Disease Case Reporting and Investigation Protocol: Pertussis has been updated. It contains up-to-date information on laboratory testing, clinical presentation, and treatment for Pertussis.

The educational flier Seasonal Influenza (Flu): Is it the Flu, a Cold, or Whooping Cough? | Wisconsin Department of Health Services is a valuable source during respiratory season.

Varicella

As of March 31, 2025, Wisconsin has 36 confirmed and probable cases statewide in 2025. Since January 1, 2025, 20 counties have had at least one case. About 56% of the cases had a positive laboratory test. While cases range in age from 4 months to 59 years, the median age of the cases is 11 years. Two individuals have been hospitalized. The majority of cases continue to occur among unvaccinated individuals with about 64% of cases having received no doses of varicella vaccine. No deaths have been reported.   

Varicella resources

DHS varicella webpage

CDC varicella webpage

CDC Laboratory testing information 

Mumps

As of March 31, 2025, Wisconsin has four confirmed cases in 2025. Cases have occurred in two counties in the western part of the state and range in age from 17 to 65 years. One individual has been hospitalized. No deaths have been reported.   

Mumps resources

DHS mumps webpage

CDC mumps webpage

DHS mumps fact sheet in English, Spanish, and Hmong

Wisconsin Adult Viral Hepatitis 2023 Surveillance Reports

The Viral Hepatitis programs have recently published the following surveillance reports:

Hepatitis A Virus (HAV) Annual Surveillance Report, 2023

Statewide Hepatitis C Virus (HCV) and Hepatitis B (HBV) Annual Surveillance Report, 2023

Wisconsin Department of Corrections Syndemics Report, 2023

Milwaukee County Hepatitis C Virus (HCV) and Hepatitis B Virus (HBV) Annual Surveillance Report, 2023

Wisconsin vaccination rate data

The immunization program has vaccination rate dashboards for influenza, COVID-19, and RSV. These dashboards display vaccination data by location, age group, and demographics. The influenza dashboard also highlights how the CDC’s Social Vulnerability Index (SVI) aligns with influenza vaccination coverage.