Data Notes for the Week of July 13
Posted on Monday, Jul. 13, 2020 at 5:54 pm
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:
We are now including demographic data for the new cases in this 14-day period.
We are showing the percent of all people tested, cases, and hospitalizations by race and ethnicity during the 14 days, and how those percentages compare to that particular demographic’s overall percentage of the Dane County population. Hispanic or Latinx people who tested positive made up 14% of cases and 22% of hospitalizations while accounting for just 6% of the population, and Black people made up 8% of cases and 19% of hospitalizations, and account for 6% of the population. Additionally, people in the 20-29 age group made up the vast majority of cases: 54% of cases were in this age group; the next largest was age 30-39 at 13% of cases.
Our average number of cases per day went up again, and percent positive tests remained yellow.
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 42 to 144, with an average of 98 cases per day. An average of 5.5% of tests were positive during this period. We are still waiting on reports from the last three days of this period, as positive tests that show up in our system are prioritized and processed by our staff more quickly than the negative. We expect the percent positivity to decrease when we receive these remaining reports (see page 3 in the snapshot for more information).
From June 27 through July 10, 1,378 people tested positive for COVID-19 in Dane County. As of this morning, 933 have had complete interviews. Here’s what we know about these cases:
- Of all 1,378 cases, 864 (63%) were tested at community testing sites (842 at the Alliant Energy Center)
- Of all 1,378 cases, 712 (52%) were young adults between the ages of 18-25
- Of 933 people fully interviewed so far, 437 (47%) reported attending a gathering or party with people outside of their household.
- Of 933 people fully interviewed so far, 302 (32%) were associated with a cluster: 183 from bars and restaurants, 40 from other workplaces, 32 from college-aged housing (including sororities, fraternities, near-campus apartments), 28 from gyms, 12 from congregate facilities, and 7 from childcare facilities.
There are signs the rate of spread may be decreasing. The “R” number estimates the rate of spread of a disease in a community. It represents the number of people who will be infected by a single individual who has an infection. For Dane County, R is calculated using a calculator produced by researchers at the London School of Hygiene and Tropical Medicine. The R number on June 27 was 1.51, the highest of the epidemic. On July 10, it was 1.09. CDC considers:
- An R of 0.33 a “rapid decrease”
- An R of 0.8 a “slow decrease”
- An R of 1.2 a “slow increase”
- An R of 1.8 a “rapid increase”
The lab timeliness and contact tracing metric is still red.
As we reported last week, lab timeliness and contact tracing are combined into one metric because we can only start tracing once we receive a lab report. The metric remained red. The Fourth of July holiday fell during this period which added an additional barrier; people took longer returning our calls over the holiday weekend.
Tying together the measures of lab processing time and time to contact positive cases gives us insight into how quickly we can isolate infection and stop it from spreading
Keep in mind this metric is asking a lot of our lab, healthcare, and public health systems: a person has to be tested, the sample has to be transported to the lab, the lab has to test the sample and input the results in the state database, our team has to collect and process the result and call the person who tested positive, and the person who tested positive has to answer their phone when we call. For this metric to turn green, that all needs to happen within 48 hours for 85% of cases.
We currently have 67 people conducting contact tracing, and 27 people supporting contact tracing work, and we are continuing to expand capabilities by hiring more.
The measure for community spread got better and went from red to yellow.
In last week’s snapshot, the community spread metric was red and 33% of cases who tested positive didn’t know where they could have gotten COVID-19. This number is now 28%, which turned it yellow. This number needs to be under 20% to be green. 62% of cases who were interviewed reported having close contact with another confirmed COVID case. It’s important to keep social circles small – 15% of cases who were interviewed were asymptomatic or presymptomatic, so anyone could be unknowingly spreading COVID if they are coming into close contact with others.
It’s critically important for folks to keep following public health recommendations, including staying home when you’re sick or feel off, wearing a mask when out, staying six feet from people you don’t live with, avoiding gatherings and parties, and basic hygiene like covering coughs and sneezes and washing your hands often. See our website for more tips.