Shelby County gets a D+ in social-distancing matrix

By Updated: April 16, 2020 6:01 AM CT | Published: April 14, 2020 5:08 PM CT

For three days, starting Thursday, the death rate from COVID-19 in Shelby County held flat at 26. Dr. Manoj Jain, infectious disease expert advising the Memphis/Shelby County COVID-19 Task Force, noticed and then looked at the website that zeroes in on population mobility, county by county, and bit his lip.

Two weeks ago, Shelby County earned a grade of B- on Unacast.com, a company that uses cellphone data to track human mobility, for the way it was keeping its distance. That helped account for the promising current numbers. 


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Monday, the daily mobility grade plummeted to a D-.

Tuesday, it had moved incrementally to D+.

“There’s a two-week lag in what you see,” Jain said. “People don’t understand. Very often, they say, ‘You just told me I am doing horrible in social distancing.’ Yes, as of two days ago, you were doing horrible. The impacts in the cases now are due to what you did two weeks ago.”

<strong>Dr. Manoj Jain</strong>

Dr. Manoj Jain

And in Shelby County, he notes, people have a tough time staying in groups of 10 or fewer. Tuesday, Unacast gave the county an F for encounter density, unchanged from Monday. Compared to national norms, people in Shelby County have made less than a 40% decrease in their “bunching up” behavior.

Davidson County, which had 1,237 COVID-19 cases as of Tuesday, second in Tennessee to Shelby County, also earned an F on its encounter density grade. But it earned an A for reducing nonessential visits by more than 70%. Shelby County has cut its nonessential visits 60-65% and gets a C.

The social distancing grade is shared with task force each morning.

On Tuesday, the state of Tennessee had a D-.

“I look around and still see a lot of  people out there, and that makes me nervous,” said Dr. Stephen Threlkeld, the infectious disease physician at Baptist Memorial Healthcare who is caring for COVID patients at Baptist Hospital-Memphis.

But based on incubation rates and how long it takes to get seriously ill with COVID-19, the number of new cases is a more immediate measure of how effectively the community is social distancing, he said.

“Deaths will be the last thing to go down. You look for incidents of infection to go down first,” Threlkeld said. “And hospitalization can be a secondary marker. Our numbers on hospitalizations have held fairly stable.”

Of the new cases reported each day, roughly 15% will require hospitalization, Threlkeld said. “If you are exposed today, on average, it will be five to eight days and up to 14 before you become ill.”


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From Monday to Tuesday, Shelby County had 20 new COVID cases, down from an average daily increase of 66 over the last six days. As of late Tuesday the total number of county cases was 1,351, with 30 deaths. According to the state Health Department, 292 patients with cases in Shelby County have recovered.

“Although numbers continue to rise, we are seeing a decrease in the rate that new cases are being detected,” said Dr. Jon McCullers, associate executive dean at the University of Tennessee Health Science Center’s College of Medicine and pediatrician in chief at Le Bonheur Children’s Hospital.

“That is an encouraging sign that social-distancing measures are working and were implemented at the right time. It is too soon to say when we might peak and decline, but I am more optimistic than one week ago,” he said.

Last week, the MD2K Center – Mobile Sensor Data-To-Knowledge – at the University of Memphis released the app mContain to help people monitor encounters that are long and close enough for transmission to occur.

So far, 477 people here are using the app, currently available to android users. When the number of users reaches 1,000, people gathering in groups of ten or more users will show on a map of the city, (mContain.com) telling others spots to avoid.

“Once we deploy the iPhone version of the app, we will make another push for more users to download the app to improve awareness of social crowding in our community,” said Shahin Samiei, assistant director for research and studies at MD2K.

“When more users download the app and the map becomes functional, we will plan to display large groups, defined as those with 10 or more simultaneously present individuals, based on current CDC guidelines,” he said in an email Tuesday.

The app is based on technology used in fitbits and other devices that monitor health by tabulating movement.

“If you want to improve your health, you increase your steps,” Jain said. “If you want to decrease your risk of COVID, you want to decrease your proximity encounters,” he said.


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Based on laxness in social distancing, Shelby County could easily see an uptick in new cases and deaths, although Jain notes the equation grows more complex nearly every day.

“A, we are wearing masks, that is a good sign. And B, we are doing a lot of testing and contract tracing. Those are good signs.”

Any uptick in future positives will be a balance of these changes, he said.

A study on the Centers for Disease Control website shows that the virus in hospitals in Wuhan, China, where it is thought to have originated, traveled 13 feet in general COVID wards.

When asked about the study in the daily press briefing Tuesday, Shelby County Heath Department health officer Dr. Bruce Randolph said the department had not changed its guidance.

“Currently, we’ll still hold onto our recommendation of distance of 6 feet separation, and continuing to wear masks and wash our hands,” he said.

As testing increases to more people who do not have symptoms, Threlkeld expects the number of positives will increase but on average, they will be cases that won’t require hospitalization, he said.

“More testing is crucial. It allows you to get a real look at the incidence of infection at a given time in the community. The antibody tests, when they become available, and we think it will be quite soon, will allow us to say who has had the infection. That will be an equally important test, just in slightly different ways. It will tell us who had it a month ago and as such, who is eligible to give plasma (for an antibody infusions).

“It tells us who is safe to take care of people, who would be safe to go into a home-health situation as a nurse or caregiver. It tells who are the people that shouldn’t be able to give it to someone else,” Threlkeld said.

Like antibodies used to prevent rabies after and animal bite, he suspects one day plasma from people who have contracted COVID and recovered could be used as preventive for others.

In a “fast food” society used to quick innovation, Threlkeld says, there is a tendency for people to think science is not working fast enough now.

“We want things fast. But we really are getting them fast. The progress is amazing, and it just keeps going,” he said, noting that research now suggests the Syrian hamster could be an animal used in COVID-19 laboratory testing.

The hamster, sometimes called a golden hamster, gets the disease similar to the way humans do. An animal model would allow researchers to do tests in live tissue that are currently not possible, Threlkeld said.

At Cornell University, he said, researchers have discovered that the “fusion region” of the virus at the base of its spike protein is “very nearly identical” to the same region in SARS and MERS, which are also coronaviruses. The similarity, he said, could be huge for finding a cure.

“We are marching very quickly. One of the things that is sometimes forgotten about this disease is that we didn’t know it existed until December in China.

“Having an animal model will be a major development,” he said.

“Even though we are forced to scatter with social distancing, in times of need like this, it forges some ties with different scientists that might otherwise be competing with one another. You can see people working together in times like these. They are trying to share information for the good of everybody.”

COVID-19 in Memphis and Shelby County: April

Topics

Dr. Manoj Jain Dr. Stephen Threlkeld Unacast.com Dr. Jon McCullers

Jane Roberts

Longtime journalist Jane Roberts is a Minnesotan by birth and a Memphian by choice. She's lived and reported in the city more than two decades. She covers healthcare and higher education for The Daily Memphian.


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