Light Change Ahead

Light Change Ahead

This week’s rise in COVID-19 cases has become a trend but by itself won’t likely scuttle the county’s economic reopening plan.

by scott barker • May 28, 2020
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The recent spike in Knox County’s COVID-19 cases is notable but not alarming, according to public health officials.

Knox County recorded 30 new COVID-19 cases over the past three days.

Dr. Martha Buchanan, director of the Knox County Health Department, said Wednesday that a review of the data showed that the trend indicates Knox County could fail to meet the benchmark for limiting the number of new cases. 

The Health Department uses traffic-light symbols on its website as visual indicators of how the county’s outbreak is progressing. All five metrics the Health Department is tracking have had green lights so far, indicating that the benchmarks are being met. 

Buchanan said the increase in new cases — 30 in the past three days — is enough to mark a trend that would change the light for that benchmark to red. But she also said the development isn’t necessarily cause for alarm.

“We expected an increase in cases, so we’re not surprised by this,” she said. “Our case count has been so low, we've only been getting a few cases a day, it doesn’t take much for it to be statistically significant.”

Counting Cases

The number of new cases is probably the easiest way for the general public to gauge the severity of the pandemic. Health officials track the number of confirmed positive cases and probable cases, but the numbers alone don’t tell all the story. 

The Health Department uses a formula based on a rolling 14-day average of new cases to determine the course of the pandemic in Knox County. If there is a three-day shift above a threshold based on standard deviations above the mean of the cases, then the light can change to yellow or red. (The Health Department updates the benchmarks page of its website on Fridays, so this week’s spike isn’t reflected in the traffic-light system yet.)

“It’s standard methodology,” said Roberta Sturm, the Health Department’s chief epidemiologist. “One day doesn’t indicate a trend. One day may indicate a cluster, whereas three days would not.”

Sturm said the Health Department altered its outcome when epidemiologists added probable cases — those in which patients exhibit COVID-19 symptoms but haven’t received a positive test result — to the total. Knox County now has 48 active cases and 10 probable cases.

Buchanan said two clusters of cases — one centered on a business and the other at a private school — helped push the numbers up, but she did not give more specific information about the locations.

“Those facilities, those organizations that are involved, are cooperating with us,” she said. “They’re giving us the information that we need, they’re helping us locate folks that might be at risk and we’ve been able to reach out to the folks at risk or in the process of reaching out to them, so that negates the need for public notification.”

Knox County has seen other clusters during the pandemic. Outbreaks within large Latino families have led to a disproportionate number of cases in the Hispanic community. Hispanic residents have accounted for 24 percent of all cases in Knox County since the outbreak began.

Charity Menefee, the Health Department’s communicable and environmental disease and emergency preparedness director, said contact tracing has not uncovered geographic hotspots or types of businesses where coronavirus transmission is more prevalent than others. “We’re not seeing a trend in clusters,” she said. “Nothing that’s jumping out.”

Other Benchmarks

A rise in new cases, even a significant one, is not enough on its own to adjust or scale back the county’s economic reboot, which moved into Phase Two this week. “That just lets us know if there’s a problem,” Sturm said. “We look at the situation as a whole.”

The Health Department’s epidemiologists look at four other datasets as well, and make decisions based on the totality of the picture. So far, the county is meeting all four of the other benchmarks.

The Health Department tracks testing, both the number administered and the time it takes to get lab results; its own capacity to respond to a wave of new cases; the healthcare system’s surge capacity; and the death rate.

More people are getting tested for the novel coronavirus. The Health Department doesn’t know the precise number of people getting tested at all private clinics and doctor’s offices, but the ones reported to the national testing database show a clear upward trajectory in testing over recent weeks. 

The time it takes for labs to provide test results keeps shrinking, which health officials say is another good sign. When the coronavirus first arrived in March, it could take 10 days or longer to receive results; now the average is about two and a half days.

The Health Department has a 31-member epidemiology team that tracks COVID-19 and conducts contact tracing to identify people who are at risk of being infected. Buchanan said Wednesday that the recent increase in cases has prompted her to add to the team. 

Another 20 Health Department employees are trained for contact tracing and more are available who could be trained quickly. In total, the Health Department could deploy 247 people to the team, including 166 employees from other Knox County government departments.

Regional hospital capacity is another dataset monitored on a daily basis. The Health Department tracks patients and ventilator usage, as well as available beds and equipment. As of May 21, hospitals in the 16-county region centered on Knoxville had 882 empty beds, 46 available intensive-care unit beds and 177 ventilators that weren’t being used.

The Health Department also monitors the COVID-19 death rate. So far, only five Knox County residents have died from COVID-19 complications, none of them in the past month.

Phase Two

Phase Two of the county’s economic reopening plan, which loosens restrictions on gatherings and business activity, started Tuesday, just as the new case numbers had begun rising.

Under the plan, the Health Department is using its benchmark data to determine whether to continue loosening restrictions next month, remain in Phase Two or return to more restrictive measures.

“One benchmark is not what we’re going to use to determine moving forward or moving backward,” Buchanan said.

One tool that will continue to be used regardless of the level of restrictions is a 14-day isolation period for people who test positive for the coronavirus.

“We don’t want you out possibly exposing other people and possibly causing other cases,” she said.

Buchanan acknowledged that a two-week quarantine is difficult, but that isolation for COVID-19 patients will be part of life as long as the coronavirus is around. “This is how we in public health and you can help break the chain of transmission,” she said.