Data Notes for the Week of September 24

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:

There was a significant decrease in the number of cases from UW during this 14-day period, and a significant increase in the number of cases not affiliated with UW.

Cases per day ranged from 29 to 487 with an average of 179 cases per day. Last week’s average number of cases per day was 170. In this 14-day period there were 2,503 total cases:

Of the 872 non-UW cases in this 14-day period, 127 (15%) were associated with a cluster: 29 from workplaces, 16 from health care facilities, 15 from sports teams, 14 from bars and restaurants, 14 from childcare facilities, 14 from college-aged housing (including apartment complexes with 10 or more cases and non-UW dorms), 9 from churches, 9 from congregate facilities, 4 from schools, 2 from weddings, and 1 from a house party.

• Of the 29 workplace cluster cases, 6 were from more public-facing and 23 were from less public-facing workplaces.
• Of the 12 total cases from schools, 2 were children and 10 were adults.
• Of the 20 total cases from childcare facilities, 15 were children and 5 were adults.

A single case in a congregate living facility (e.g., long term care facilities), a childcare facility, or a school initiates a facility investigation by our staff. These types of facilities are prone to outbreaks and can contain vulnerable populations. Our case investigators work with them to ensure they are following best safety practices. The goal is to prevent a cluster of cases from occurring within the facility.

In this 14-day period, there were 8 schools, 6 childcare facilities, and 1 congregate facility that had a single case but have so far prevented further spread from occurring.

Ages 18-22 made up a majority of both UW and non-UW cases during this 14-day period. However, this was the only age group that saw a decrease in the number of cases compared to last week’s snapshot; all other age groups (with the exception of 90+ which had zero cases last week and this week) had a higher number of cases this week compared to last week (age groups specified on page 3 of the snapshot).

UW-Madison students and staff make up 65% of Dane County cases, down from 76% last week.

During this 14-day period, 1,612 UW students and 19 staff (1,631 total) tested positive, making up 65% of our total cases. Of the 1,631 UW cases in this 14-day period:

• 576 (35%) were linked to dorms
• 144 (9%) were linked to fraternities and sororities
• 510 (31%) were linked to apartment complexes on or near campus that have at least 10 or more cases
• 63 (4%) were associated with a cluster: 40 were from UW sports teams, 13 were from UW campus facilities such as dining halls, 3 were from restaurants and bars, 3 from health care facilities, 2 were from a house party, 1 was from a church, and 1 was from a congregate facility.

Note that these are not mutually exclusive: a student could, for example, live in a dorm but also be a member of a fraternity.

The target for grades 3-5 was not met this week.

The K-12 school metrics are detailed on our website. The Wisconsin Supreme Court issued an injunction that allows K-12 schools in Dane County to fully open for in-person instruction. We are disappointed in this decision and strongly urge all schools to continue voluntary phasing-in of classes for in-person instruction for grades 3-12. We will continue to update data weekly and advise schools on their reopening plans.

The lab timeliness and contact tracing metric continues to be red but is largely affected by lab timeliness.

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. During this period 54% of cases were contacted by public health within 48 hours of being tested. 45% of positive tests were reported to us within 24 hours, and 73% of cases were interviewed within 24 hours of receiving their test result.