The collaboration in Louisville working to battle the coronavirus,the Co-Immunity Project, reported last week that a recent round of tests on health care workers saw a significant increase in infections — about three times higher than an initial round. 

Researchers looked for rates of positive virus cases and antibodies, which can show how many doctors, nurses and other front-line workers had previous exposure. They found the big increase mirrored a boost in positive virus cases seen in the general population during July, when compared with May.

The effort, a collaboration between University of Louisville researchers and the city’s three main health systems, has set out to document COVID-19 prevalence rates in Jefferson County, identify promising treatments and eventually build a blood plasma bank to help patients fight off the virus.

In its first rounds, the Co-Immunity Project has focused on both health care workers who have had high