Our partner's grandchildren here in Summit, South Dakota, returned to school last week, so we're paying somewhat more attention to COVID-19. While the classes in the local public school are very small, making social distancing much easier than in larger districts, we're still concerned that the kids may be exposed.
Governor Kristi Noem first closed the state's schools on-site temporarily in March, then on April 6 announced she was keeping learning online and remote for the remainder of the school year.
Schools are opening in the old normal fashion this fall, though the public health data for the state isn't "normal."
In the Sunday Sioux Falls Argus Leader, Jonathan Ellis reports in Active COVID-19 infections continue to outpace recoveries:
The 141 new cases were detected out of 1,230 individuals tested for the disease, for a daily positive rate of 11.5 percent, the eighth consecutive day in which the positive rate has exceeded 10 percent.
There's nothing in the article with which to interpret that rate, so we turned to Johns Hopkins COVID-19 School of Public Health Expert Insights COVID-19 Testing: Understanding the “Percent Positive," by David Dowdy and Gypsyamber D’Souza to understand what this means:
As COVID-19 outbreaks continue to flare up across the U.S., the need for coronavirus testing remains urgent.
Individuals rely on test results to guide their medical treatment and decisions on whether to self-isolate. Public health officials rely on the results to track the state of the pandemic, and policymakers use this information to guide decisions on reopening schools and businesses.
One number—the “percent positive”—is often cited in these decisions. In this Q&A, Epidemiology faculty David Dowdy, MD, PhD ’08, ScM ’02, and Gypsyamber D’Souza, PhD ’07, MPH, MS, explain what this term means and why it matters.
What is the “percent positive” and why does it matter?
The percent positive is exactly what it sounds like: the percentage of all coronavirus tests performed that are actually positive, or: (positive tests)/(total tests) x 100%. The percent positive (sometimes called the “percent positive rate” or “positivity rate”) helps public health officials answer questions such as:
- What is the current level of SARS-CoV-2 (coronavirus) transmission in the community?
- Are we doing enough testing for the amount of people who are getting infected?
The percent positive will be high if the number of positive tests is too high, or if the number of total tests is too low. A higher percent positive suggests higher transmission and that there are likely more people with coronavirus in the community who haven’t been tested yet. . . .
How high is too high?
The higher the percent positive is, the more concerning it is. As a rule of thumb, however, one threshold for the percent positive being “too high” is 5%. For example, the World Health Organization recommended in May that the percent positive remain below 5% for at least two weeks before governments consider reopening. If we are successful in bringing coronavirus transmission under control, this threshold might be lowered over time. To further relax social restrictions and allow very large gatherings or meetings of people traveling from many different areas, for example, we would want a lower threshold.
As of July 2020, some countries (for example, Australia, South Korea, and Uruguay) and U.S. states (for example, New York, Maine, and Connecticut) were well below the 5% threshold, with 1% of tests or fewer being positive—while other countries (for example, Mexico and Nigeria) and states (for example, Mississippi, Nevada, and Florida) had percent positive levels higher than 15%, far above this cutoff. (See Becker’s Hospital Review and the Johns Hopkins Testing Tracker.)
The percent positive is a critical measure because it gives us an indication how widespread infection is in the area where the testing is occurring—and whether levels of testing are keeping up with levels of disease transmission.
We're not yet Mississippi, but since Governor Noem's brand is wide-open, we're not likely to see assertive public health measures in response to the relatively high positivity rate.
This was not the case last spring, Cory Allen Heidelberger reminded readers at Dakota Free State in Noem’s Old Back-to-Normal Plan Says SD Schools Should Close Again:
. . . Back in spring, Governor Kristi Noem said we could get “back to normal”—i.e., reopen the schools—if our coronavirus numbers showed a “downward trajectory of documented cases within a 14-day period in areas with sustained community spread.”
Every South Dakota county with a state university or vo-tech currently has moderate to substantial community spread of coronavirus. We are one of eleven U.S. states/territories showing an increase in our 14-day average of newly reported cases. Our weekly average for newly reported cases per day as of yesterday was 143, a 54% increase from two weeks ago and higher than the worst surges in April and May. . . .
Science said back in March that our coronavirus quarantine would not be one and done. Science told us back in March that if we wanted to save two million lives in the U.S., we had to plan for “adaptive triggering,” a rolling series of social distancing and school closures. Noem’s own “Back-to-Normal” plan tells us it’s time for the next installment of distancing and home-learning.
A note on contact tracing in South Dakota
One of the claims made by fans of Noem is that there's no contact tracing in South Dakota. This simply isn't true.
South Dakota News Watch's Nick Lowrey reported last week in As COVID-19 cases rise, experts question effectiveness of contact tracing in S.D. and across the U.S.:
South Dakota Department of Health leaders say their contact-tracing efforts are keeping up with the increasing caseload. The state’s goal is to make contact with everyone who tests positive for COVID-19 in South Dakota within 24 hours of the department being notified of the new case.
The 131 contact tracers now working for the health department are making initial contacts with known COVID-19 patients within about 15 hours on average, said Cassie Deffenbaugh, who leads the contact-tracing team. The state contact-tracing workforce has grown to five times its pre-pandemic size since March, and has been able to identify 35,000 close contacts of coronavirus patients during the pandemic so far. Deffenbaugh said she is confident that the state’s contact tracers would be able to keep up with the virus.
“We are adequately staffed to be able to support our current workload,” Deffenbaugh said. “We are constantly assessing to make sure we are adequately staffed at this time and that we will be moving forward.”
But some disease researchers say the contact-tracing workforce is not widespread enough in South Dakota to handle the rising number of cases. . . .
Back in April, Jonathan Ellis reported in State expanding contact tracing capabilities in key move against coronavirus at the Argus Leader:
South Dakota health officials this week have beefed up the number of workers conducting contact tracing on people who contract COVID-19.
It’s not an army, exactly. More like a company in military terms, but the 131 people now doing that work increased from fewer than 90 at the beginning of the week in what Department of Health Secretary Kim Malsam-Rysdon described as a “labor intensive” process.
The Centers for Disease Control and Prevention issued an advisory this week that states should begin building a trained contact tracing team now. . . .
“If you’re getting a call from the Department of Health, please pick up,” Malsam Rysdon said Friday. “We want to share information with you so that you can be safe, so that you can keep other people safe.”
State officials have been promoting the use of a voluntary cell phone app, Care19, that would enable them to access location data for people who test positive. Some countries are aggressively using cell phone data to underlie their contact tracing programs.
The Governor also urged residents to download that Care19 app, which didn't work out so well, the Washington Post reported in One of the first contact-tracing apps violates its own privacy policy.
Screengrab: From Dakota Free Press, New reported cases (bars) by day and (red line) seven-day average of daily reported coronavirus cases in South Dakota, March 1–August 23, New York Times, retrieved 2020.08.24.
Comments