Data Notes for the Week of August 20

Today we released this week’s data snapshot. If you’re new to the data snapshot, we publish a weekly summary of the status for each of our metrics (you can find past issues on our data and metrics page). We have a few notes for this week’s issue:

Our average number of cases per day is still red but has continued to decline.

The number of cases per day metric was red in the last data snapshot, and it remained red during this 14-day period. Cases per day ranged from 12 to 79, with an average of 45 cases per day. Last week’s average number of cases per day was 50. Since July 13, Dane County’s average number of cases per day has gone from 98 to 45 today. In this 14-day period, there were 628 total cases:

• Of all 628 cases, 408 (65%) were tested at community testing sites (405 at the Alliant Energy Center).
• Of 565 people who have been fully interviewed so far, 209 (37%) reported attending a gathering or party with people outside of their household.
• Of 565 people fully interviewed so far, 300 (53%) identified the likely source of infection as close contact with another lab-confirmed COVID-19 case.
• Of 565 people fully interviewed so far, 97 (17%) were associated with a cluster: 30 from workplaces, 22 from congregate facilities, 14 from bars and restaurants, 11 from childcare facilities, 6 from large gatherings, 6 from healthcare settings (such as home health or hospitals), 3 from sports teams, 2 from gyms, and 3 from other clusters.
  • Of the 11 cases from childcare facilities, 2 were children and 9 were adults.
  • Of the 30 cases from workplaces, 12 cases were from more public-facing businesses (such as hotels and golf clubs) and 18 were from less public-facing businesses (such as manufacturing facilities and contractors).

The lab timeliness and contact tracing metric continues to improve.

Lab timeliness (how quickly labs are reported to us) and contact tracing (how quickly we can reach out to cases) are combined into one metric because lab timeliness directly affects contact tracing. This metric has increased yet again: 83% of cases were contacted by public health within 48 hours of being tested, compared to 75% from our last snapshot. This metric will turn green when we’re able to contact 85% of all cases within 48 hours of when they got tested.

Four out of every ten people with COVID-19 do not know where they could have been exposed.

The community spread metric is unchanged from last week: 40% of people with COVID-19 did not know where they could have been exposed. A high percent of cases who don’t know how they got sick means there are likely people unknowingly spreading the virus in the community.

Dane County is still classified as “high activity level” on the Wisconsin Department of Health Services (DHS) COVID-19 Activity Level Tracker.

Our Forward Dane metric for cases (see the first section of this blog) accounts for burden but not trajectory. The DHS metric combines the burden of cases over a two-week period (number of cases per 100,000 residents) and the trajectory, which measures the percent change in cases from the previous week to the current week and whether that change is statistically significant.

As of the DHS update on 8/19/20, Dane County has a high burden of 110.5 cases per 100,000 residents, and a trajectory of no statistically significant change in the number of cases from the most recent 7-day period compared to the prior 7-day period. This puts us at a high activity level. We want to reduce our activity level in order to better control the spread of COVID-19 in our community.