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New Data Snapshot shows 65 percent of new Dane Co. cases are from UW


Late this afternoon, Public Health of Madison and Dane County updated their Data Snapshot for the week of August 25 – September 7 with a look at those past two weeks’ data including Department of Health Services’ activity level metric.

The activity level metric measures the burden of cases within the last two week period (number of cases per 100,000) and the trajectory, or the percent change in cases from previous to the current week and whether or not that trajectory is statistically significant.

According to the update, the current activity level for the county remains high as the trajectory has continued to grow, as it did last week, and the growth continues to be statistically significant. Dane County has grown to 242 cases per 100,000 residents, more than doubling last week’s 120 cases per 100,000.

The data snapshot does not include the more than 500 cases confirmed September 9 and 10.

For all of Dane County, including the University of Wisconsin, a total of 1,321 new cases were confirmed in the two-week period, with 41 percent tested at community sites and another 41 percent tested by University Health Services. From all cases, contract tracers have been able to interview 1,213 cases with 32 percent of those indicating that they attended a gathering or party with those outside their household, and 62 percent identifying that the source of their infection came from close contact with another lab-confirmed case.

The new Snapshot also reported specifically on UW cases this week. As students, staff and faculty return to campus with students moving back in as early as August 15, Public Health began to track positive COVID cases for students, faculty and staff as early as July 28. From August 25 through September 7, UW students and staff made up 65 percent of Dane County’s new cases — 856 total cases. Of that 856, 846 were UW students and 10 were staff. 98 percent or 828 of UW students testing positive for those two weeks were between ages of 18-22 with 441 associated with the following clusters (with some students associated in more than one cluster per PHMDC):

  • 426 from college aged housing including sororities/fraternities and near-campus apartments
  • 17 from UW sports teams
  • 2 from congregate facilities
  • 2 from a gathering

For all of Dane County, 41 percent of all cases were associated with known clusters with those listed previously but also from:

  • 14 from work places
  • 10 from congregate facilities
  • 10 from childcare facilities
  • 9 from bars and restaurants
  • 6 from weddings that took place outside of Dane County

The largest age group of positive cases for those two weeks were from the 10-19 group which made up 50 percent of all cases. Those aged 20-29 made up 30 percent of all cases as well. Dane County and Public Health broke down further the cases among teens and children not associated with UW. Four percent of cases – 52 cases – were children aged 0-17. From those 52, 25 were aged 12-17, 18 were aged 8-11, 6 were aged 5-7 and 3 were aged 0-4. The only information about where these children were infected was that 2 of the 52 cases were at childcare facilities.

Currently, for August 25 – September 7, Dane County has also grown in average cases per day from 45 cases to now averaging 94 cases per day. This metric remains red according to the update and will continue to be red until we average fewer than 20 new cases per day to move to yellow and below four cases per day to move to green. Further, PHMDC requires a daily new case count below 39 for four consecutive weeks to open schools for grades three through five, and below 19 for four consecutive weeks to open grades six through twelve, for in-person instruction. PHMDC has also said that if the daily case count exceeds 54, it may require all schools to close, even for kindergarten through second grade, which currently may remain open.

For those dates, the percentage of those who test positive that have been contacted within 48 hours of their reported results decreased from last week’s 73 percent to 55 percent. This changes the metric from yellow to red. PHMDC guidelines require it to be 85 percent for it to turn green. Though last week’s snapshot reported that the percentage of those who tested positive who did not know where they would have gotten COVID from was at 40 percent, this week it decreased to 33 percent. Despite the improvement, this metric remains red.

Communities of color are overrepresented in hospitalizations and in cases. According to the snapshot, those who identify as Hispanic/Latinx are underrepresented in all tests. Though six percent of the population, they continue to only be five percent of all tests during that two week period. Though improved in the overall percentage of all cases from last week dropping from 13 to 9 percent as well as hospitalizations decreasing from 56 percent to 33 percent, the inequity is still heavy for that group. For both those who are Black and Asian, though still underrepresented in testing in comparison to their population, both groups are underrepresented for those two weeks in all cases as well.