The Wisconsin Department of Health said Tuesday that 19 people who reported that they voted in or worked the April 7 election tested positive for coronavirus in the days following.

Jennifer Miller, department spokesperson, told TPM that the 19 tested positive after April 9. Experts consider the incubation period for the virus to be two to 14 days.

However, she added that there is no way to know for certain that those 19 became infected by their interactions while voting in person or working the polls, and not from other “possible exposures.”

“Since we only have data on positive cases (without a comparison group of people who were not tested or tested negative), there is no way to know with certainty if any exposures at the polls that are reported are in fact attributable to COVID-19 illness,” she said.

That conclusion slightly differs from the one put forward by the Milwaukee Department of Health earlier on Tuesday.

Officials there confirmed that seven people had fallen ill in connection to the election, though adding that they only currently have 30 percent of the data on the relevant cases. The department’s communications director, Shawn Benjamin, told TPM that they expect to have a more comprehensive report out on Friday.

The controversial April 7 election was held in-person despite attempts by Gov. Tony Evers (D) and Democrats to have it pushed back. After state Republican lawmakers lodged challenge to Evers’ executive order, the majority-conservative state Supreme Court ordered the election be held as planned.

Due to elections workers calling in sick, or afraid of becoming so, many polls were shuttered and voters forced to wait in long lines. In some places, like Milwaukee, people had to cram into five polling places — down from the city’s usual 180.