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UPDATE FROM METRO PUBLIC HEALTH DEPARTMENT EPIDEMIOLOGY TEAM ON COVID-19 IN DAVIDSON COUNTY

10/15/20

UPDATE FROM METRO PUBLIC HEALTH DEPARTMENT EPIDEMIOLOGY TEAM ON COVID-19 IN DAVIDSON COUNTY

COVID case counts are increasing due to community spread. There are several factors likely driving the current case counts and metrics, including:

  • Overall testing numbers
  • COVID among school-aged kids and their families
  • Social activities

Testing Numbers
Testing numbers are higher across the county right now than in August. A large driving force is Vanderbilt’s ongoing, routine testing regimen among University students, accounting for 20.5% of tests in September, and through October 6 had accounted for about 20% of the testing in the county for October. The attack rate among the VU community is lower than the county; weekly and daily attack rates in Davidson minus VU were 5% in September and 5.65%, respectively, in October as of 10/6 compared to 3.8% and 4% overall. Cases are increasing in every ZIP code. Residents in some ZIPs continue to get tested less than others, and true cases are possibly higher than we know (as with any infectious disease).

Cases Among School-Aged Kids and Their Families
There is a continued increase in incidence rate among 0-17 year-olds, slight increase in 18-24 year-olds, decreases in 25-34 year-olds, and increases in 35-44 and 45-54 year-olds. The incidence rate for 0-17, 35-44, and 45-54 year-olds have increased by 93, 27.3, and 32.5%, respectively, since the beginning of September. Perhaps this represents an increase among school children and their parents/families.

We have several new clusters involving schools and universities, primarily sports teams and weekend activities with classmates like parties, bonfires, sleepovers, etc. Most infections among school aged students and school staff do not appear at this time be driven by in-class transmission, but rather extracurricular activities and social gatherings.

Schools that have closed due to high numbers of cases and/or close contacts include St. Bernard’s, St. Cecilia, and Cora Howe.

Social Activities
Since the beginning of Week 36, we’ve identified 36 clusters, 17 of which were in a school/university setting (including school sports teams), social gatherings, religious settings, or bars/restaurants.

Some specific examples include at least 12 cases at a local karaoke bar, 10 confirmed cases at a church service, at least 13 confirmed cases at a 7th grade party among private school students, and a large volleyball tournament that resulted in 32 confirmed infections among student athletes and staff who reside in Nashville. Additionally, new clusters identified this week included confirming 4 cases associated with a wedding on 9/26, 4 cases associated with a wedding on 10/3, and 5 cases associated with church-related social events.

Case interviews are resulting in longer lists of places attended during exposure periods, indicating that people are getting out and doing more in public settings.

Conclusion
Nashville-Davidson County saw approximately 200 cases a day in early June (216 on 6/8). 16 days later, the daily case count doubled and reached 500 on 6/24. The peak case count was on 7/6 with 628 cases, then declining. This decline was coincidental with the return to a modified phase 2 and implementation of a mask mandate. Cases counts generally declined through much of September but have increased as of 10/6 to more than 200 cases per day. When including only September cases onward, NDR has a doubling rate of 17.8 days with a 5-day lag, meaning that with current trends, the count could return to 400 cases per day during October.