COVID-19: Frequently Asked Questions

From our Wisconsin COVID-19 Summary Statistics dashboard, you can see the actual new daily cases and deaths by hovering your cursor over the seven-day average number on desktop, or by tapping the seven-day average number on a mobile device.

Our Wisconsin COVID-19 Summary Statistics dashboard shows case and death data by the date it was reported to us. That means, our numbers are typically lower on weekends and on Mondays because there are less staff working on weekends to actively load new cases and deaths into the Wisconsin Electronic Disease Surveillance System (WEDSS). That’s also why Tuesdays may look a little higher in cases and deaths. By smoothing out those day-to-day fluctuations with a seven-day rolling average, we get a more representative picture of COVID-19 in Wisconsin.

The reason we use cases and deaths by report date on the summary dashboard is because those are the most up-to-date numbers we have available and we want to make those available publicly as soon as we can. This is important for local decision makers, public health practitioners, and the public to see the real-time impact of COVID-19 on their community. However, we also show cases by date of symptom onset or diagnosis and deaths by date of death, which generally follow the same curve as cases/deaths based on when they’re reported, but include an earlier date as to when someone actually started having symptoms of COVID-19, or passed away from the disease. That information is always a bit delayed because those details often come from case interviews or review of a death abstract.

Probable cases are included because the public health follow-up and recommendations for probable and confirmed cases are the same. As antigen testing has become more accessible, probable case classifications are more common. We recognize the role that probable cases have in our efforts to stop the spread of COVID-19. For the full definition of a probable case, see the “About our Data: How do we measure this?” drop-down underneath the Wisconsin COVID-19 Summary Statistics dashboard.

As of May 27, 2021, we have improved the way we report daily cases and deaths to make our data more precise. The new method allows corrections due to quality assurance to be counted on the date when a case or death was first reported, rather than affecting the current daily count of cases or deaths. This method makes sure data cleaning and quality assurance efforts won't impact current daily counts. The new historical data file behind this improved method is available for download in the "How can I download DHS COVID-19 data?" section at the bottom of the page.

The following visualizations have been updated to utilize the new historical data file:

• Wisconsin COVID-19 summary statistics
• New confirmed COVID-19 cases by date confirmed, and seven-day average
• New deaths reported among confirmed COVID-19 cases by date reported

DHS has been able to increase data quality assurance efforts as state-wide case counts have decreased. This effort includes merging duplicate case records and correcting disease status in the Wisconsin Electronic Disease Surveillance System (WEDSS). A majority of the changes are a result of case status being corrected from "confirmed" to "probable." Confirmed and probable cases are classified according to a standardized case definition (for example, based on laboratory testing). However, for the purposes of public health follow-up, the health recommendations for confirmed and probable cases are the same. Quality assurance efforts are a critical piece of our efforts to finalize COVID-19 cases and deaths.

DHS also continues to reduce the number of "unknowns" across several of our data fields. In the case of cleaning "unknowns," there may be shifts in the categorization of COVID-19 cases or deaths by various categories. This shift will be significant the first time this matching process is conducted. This effort is being carried out first among COVID-19 cases by race and ethnicity, with future updates planned for cases among health care workers.

In the future, reported COVID-19 deaths will be compared with vital records death reports to assure we have captured all death reports. This work will likely result in shifts in the number of COVID-19 reported deaths.

Information on COVID-19 cases is collected through the standard communicable disease surveillance system used for all other reportable communicable diseases in Wisconsin. Laboratories and health care providers are required to report information (including the person’s name, birth date, address, type of test, test result) on cases of COVID-19 (and other reportable communicable diseases) to the health department. This information is most often transmitted to DHS and local health departments into the Wisconsin Electronic Disease Surveillance System (WEDSS) through an electronic submission or data feed. Sometimes information is also transmitted manually through faxes or phone calls.

After the information is received into WEDSS, local health departments attempt to contact the person (and in some cases the person’s health care provider) to gather more information. This includes getting details about the person’s illness (symptoms, whether hospitalization was required) and how the person might have become infected (travel history, any known contact with a COVID-19 case). For the purpose of contact investigating, this also means asking who the person had contact with before getting COVID-19. Local health departments or DHS contact tracing staff enter this information into WEDSS. It is not uncommon for information about cases to be delayed or incomplete in WEDSS. This is because public health may have trouble contacting the person with COVID-19 or the person might not provide all of the information required.

Based on the laboratory results and other available information, local health departments and DHS classify cases according to the standard, national COVID-19 case definition from the CDC.

Only cases with positive test results using a confirmatory diagnostic test that detect the genetic material of SARS-CoV-2, the virus that causes COVID-19, are classified as a confirmed case of COVID-19.

A case is classified as probable if they are not positive by a diagnostic, confirmatory test, but have met one of the following:

1. Test positive using an antigen test method
2. Have symptoms of COVID-19 AND known exposure to COVID-19 (for example, being a close contact of someone who was diagnosed with COVID-19) and no molecular or antigen test was performed
3. COVID-19 or SARS-CoV-2 is listed on the death certificate

A detailed surveillance case definition for COVID-19 probable cases (used by public health and not to be used for making diagnostic or clinical decisions) is available under Reporting and Surveillance Guidance on the COVID-19 Health Care Providers webpage.

Visit our disease reporting page to see the diseases and conditions that must be reported to public health. You can also learn more about case reporting methods and contact information.

The number of confirmed cases is the number of people diagnosed with COVID-19 using a molecular diagnostic test (a test to detect RNA, the genetic material of SARS-CoV-2, the virus that causes COVID-19). Prior to October 1, 2021, if a person tested positive more than once, they were only included as a confirmed case once.

Beginning on October 1, 2021, due to the updated Centers for Disease Control and Prevention's (CDC) surveillance case definition, a person may be reported as a confirmed case more than once if they have more than one positive molecular diagnostic tests that are more than 90 days apart.

The number of newly reported COVID-19 cases can fluctuate from day-to-day depending on when the testing occurs and how the data are collected and processed in WEDSS. For example, less COVID-19 data are processed over the weekend compared to during the week. This often results in fewer new cases being reported on Mondays and more new cases being reported Tuesdays. Rather than focusing on the number of new cases on any given day, it is more important to monitor the overall trend in the number of new cases. For example, the "New confirmed COVID-19 cases by date confirmed, and seven-day average" chart includes a line of the seven-day average. This line smooths out these day-to-day fluctuations in the numbers of cases reported and more clearly shows the trend in new cases. For more information on how COVID-19 cases are tracked and reported, see our fact sheet.

As individual cases are investigated by public health, there may be corrections to the status and details of cases or deaths that result in changes to this information. Some examples of corrections or updates that may lead to changes to our data, such as case and negative counts and deaths going up or down, include:

• Update or correction of case's address, resulting in a change to their location of residence to another county or state,
• Correction to laboratory result,
• Correction to a case's status from confirmed to unconfirmed (for example, if they were marked as confirmed because a blood test detecting antibodies was positive instead of a test detecting the virus causing COVID-19),
• De-duplication or merging and consolidating case records,
• Update of case's demographic information from missing or unknown to complete information.

DHS classifies deaths according to the national standard case definition outlined by the CDC and the Council of State and Territorial Epidemiologists (CSTE).

According to that definition, COVID-19 deaths are those that have a death certificate that lists COVID-19 disease or SARS-CoV-2 as an underlying cause of death or a significant condition contributing to death. Deaths must be reported by health care providers or medical examiners/coroners and recorded in WEDSS by local health departments in order to be counted as a COVID-19 death. Deaths among people with COVID-19 that were the result of non-COVID reasons (e.g., accident, overdose, etc.) are not included as a COVID-19 death.

No. If the death certificate indicates that the cause of death was a result of reasons not related to COVID-19 (for example, death related to an accident, overdose, or other non-COVID-related conditions) and COVID-19 is not listed on the death certificate as contributing to the death, the person is not included as a COVID-19 death.

No. Only persons who have documentation in WEDSS of being admitted to the hospital are considered a COVID-19 hospitalization. If a person is tested while in the emergency department and is not admitted, they are not considered a COVID-19 hospitalization.

The Wisconsin Immunization Registry (WIR) is an online system that tracks immunizations given in health care settings into one record for Wisconsin citizens. Due to the majority of health care organizations that report, WIR has the most up-to-date records for Wisconsin patients. For more information on how to access your own vaccine record, visit the DHS WIR webpage.

WIR receives information from the Wisconsin Vital Statistics program, doctor's offices, hospitals, employee health sites, schools, health maintenance organizations, Medicaid, the Wisconsin Lead Program, and Minnesota and Michigan's immunization registries.

There are roughly 3,800 health care provider locations and 3,200 schools and school districts across Wisconsin that report to WIR. Many of these health care providers send data to WIR through data exchange. With data exchange, as soon as an immunization is entered into a chart at the doctor's office, it is automatically sent to WIR. Other health care providers manually enter data into the online system or submit immunizations through a flat file, which is a formatted file with multiple individuals that can be uploaded to WIR.

Typically, anyone that does not want their immunization history shared in WIR can request to opt-out of the database. However, this option is not available for COVID-19 vaccination due to CDC guidelines.

Reporting to WIR is not mandatory unless the provider is part of the Vaccines for Children (VFC) and/or Vaccines for Adults (VFA) programs. Pharmacists who immunize children aged 6-18 have been required since 2015 to submit immunization data within 7 days of administering a vaccine.

The CDC also mandates reporting of all COVID-19 vaccination administration to WIR. CDC has recommended all COVID-19 immunizations administered be submitted to their state's registry within 24 hours.

Both. It is important that we know where a person went to get vaccinated and their primary address. Knowing where someone went to get vaccinated can help us determine how to best distribute doses. Vaccine coverage data is calculated using people's primary addresses. This is why vaccine coverage rates can sometimes fluctuate; if enough people move to a different area, they now contribute to the vaccine coverage in that area and no longer contribute to the coverage at their old address.

Vaccinations come to WIR either directly from the location's medical chart system or from staff manually entering vaccine data to WIR. With both processes, there is some form of manual entry that occurs and is subject to human error. As such, it is reasonable that entry mistakes can occur and may affect the data that is reported to the website.

As individual vaccinations are investigated by public health, there may be corrections or updates to the details reported in WIR that result in changes to this information. Some examples of corrections or updates that may lead to changes to our data, such as the number of doses administered going up or down, include:

• Removing duplicates or merging and consolidation of records
• Updating a patient's address to a different county or state
• Updates or corrections to the manufacturer code reported in WIR
• Updates or corrections to a patient's information in WIR

Data on this page may differ from data reported on the CDC COVID Data Tracker due to the fact that data may be updated on different schedules and reflect data "as of" different dates or times of day. There may also be a delay between the time a vaccination record appears in the state system and when it is received by CDC.

In addition, the CDC requires we report the newest data that we have available. Unfortunately, this does not allow the necessary time to check the data for accuracy and reach out to providers to investigate any entry errors. At this time there is no way for us to submit corrections to the CDC. As such, the CDC data will never align fully with the data we report on the COVID-19 vaccine data page.

The number of newly reported COVID-19 cases can fluctuate from day-to-day depending on when the testing occurs and how the data are collected and processed in WEDSS. For example, less COVID-19 data are processed over the weekend compared to during the week. This often results in fewer new cases being reported on Mondays and more new cases being reported Tuesdays. Rather than focusing on the number of new cases on any given day, it is more important to monitor the overall trend in the number of new cases. For example, the "New confirmed COVID-19 cases by date confirmed, and seven-day average" chart includes a line of the seven-day average. This line smooths out these day-to-day fluctuations in the numbers of cases reported and more clearly shows the trend in new cases. For more information on how COVID-19 cases are tracked and reported, see our fact sheet.

Booster doses and additional doses server different purposes for different groups of people. Data on the COVID-19 vaccines data page come from the Wisconsin Immunization Registry (WIR). Records in WIR do not contain any information beyond a patient's immunization history and some basic demographic information. As such, there is no way to tell from WIR data whether a dose beyond the completion of the primary COVID-19 vaccine series was given as an additional or booster dose.

The number of newly reported COVID-19 cases can fluctuate from day-to-day depending on when the testing occurs and how the data are collected and processed in WEDSS. For example, less COVID-19 data are processed over the weekend compared to during the week. This often results in fewer new cases being reported on Mondays and more new cases being reported Tuesdays. Rather than focusing on the number of new cases on any given day, it is more important to monitor the overall trend in the number of new cases. For example, the "New confirmed COVID-19 cases by date confirmed, and seven-day average" chart includes a line of the seven-day average. This line smooths out these day-to-day fluctuations in the numbers of cases reported and more clearly shows the trend in new cases. For more information on how COVID-19 cases are tracked and reported, see our fact sheet.

Yes. Additional and booster doses of COVID-19 vaccines are included in the total vaccine doses administered as well as doses administered by manufacturer and by day.