The COVID Report with David Blake: Public health utility
Friday, Sept. 4
There has been some concern about primary and secondary schools starting, and in Columbia County, GA, schools started August 3rd. They did not start normally.
A quarter of students were learn-from-home, and the rest were split on day schedules to reduce the density of students per day. Many extracurricular activities were not held. Mask adherence in schools is reportedly quite good. What has this month shown us?
A plot of cases in Columbia County is shown below.
The plot above, color coded age demographics, dates cases to the date of the This is an epidemic curve test.
You can see the summer wave taking off when bars were opened and restaurant capacities increased June 13th, and those infection-generating activities are always going to limit our recovery. But Aug 3, cases start to decline.
In the 5-17 age demographic, there is a modest uptick in the middle of August, but this corresponds to the time AU-Health expanded pediatric testing. We’ve gone over, in this blog, how most infections in the 5-17 age group will not be tested/confirmed, and how surveillance testing is the only way to know if infection is spreading in school.
But at this point we can confidently say that on the backdrop of bars and restaurants generating a huge number of infections every week, primary and secondary schools are much less of a problem. I have a child attending school in Columbia County, and I am comfortable with it.
I made a plot of percent infected in Columbia County, and it uses provisional data instead of epidemic curve data. For testing to have public health utility, the date of the report must be within two days of the date of the test.
The plot dates the cases to the date of the report.
You can plainly see from comparing these two curves how far we are from having testing that has public health utility. The issue here is that for public health utility, you need to inform people they are positive in time to reach their contacts “before” their contacts expose others.
Most experts put this time limit at two days from symptom onset. Near the beginning of July, the average time from testing to reporting was closer to two weeks. Our testing has consistently been useless for blocking the chain of infectious transmission.
A huge other cause of this problem was the early decision by the federal government to reimburse all COVID testing, with no time limits set on test turnaround.
Businesses responded rationally from a fiscal point of view and took as many samples as they could, and got backed up. I was critical of the federal government at that point, and now, and suggested we instead offer public health incentives.
Only reimburse tests that are returned within 48 hours of the person contacting public health. And, reimburse tests for people who test positive for the first time double. We want to incentivize testing to find all the positives, and not to take a huge number of swabs into a backlog. Our test turnaround time is, however, getting better.