An Imperfect Tool: Inside The Human Science of Contact Tracing


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A team of contact tracers, image from Unsplash.
By Chris Bowling

The march to the frontlines to contain the coronavirus starts each morning as the sun rises over a South Omaha home.

The smell of brewed coffee fills the air as Rachel Heinz, a public health nurse with the Douglas County Health Department, gets out of bed and sits down at her laptop to click through e-mails and Slack messages. At 8:30 a.m. little faces start to fill her laptop screen. These are the 90 people of Douglas County’s team of contact tracers, public health employees who spend their days calling those who’ve tested positive for the coronavirus to find the virus and quell its spread.

“This has been around for a few months but it’s still a changing situation,” said Heinz, the team lead for Douglas County’s contact tracers. “It’s really scary for people.”

One by one at that 8:30 a.m. meeting, they give updates, ask questions and add to a growing mosaic of numbers and stories that, without a vaccine or treatment, is public health’s only tool to stop the coronavirus, especially as businesses reopen and protesters convene in the hundreds or thousands.

But contact tracing is far from perfect. The data relies on a chain of human transfers, trust that an infected person provides accurate information and that human error won’t dirty the process. And even more than that, they’re up against a virus they can’t seem to outrun.

“This is a massive undertaking,” said Justin Frederick, supervisor of Communicable Disease Epidemiology, the portion of the health department that oversees contact tracing. “And in my opinion, it’s really an uphill battle as people start to go back to normal.”

How it works

Before the pandemic struck Douglas County, racketing up cases into the thousands, the Douglas County Health Department traced things like tuberculosis or sexually transmitted infections. The team consisted of about five people.

Since then it’s grown to 30 county health department employees and 60 state employees who meet twice daily, once at 8:30 a.m. and again at 6 p.m., to talk trends they’re seeing in different demographics, zip codes and industries. The department’s epidemiologists compile that information along with strategic recommendations into a report for the department’s director Dr. Adi Pour.

“The CDC doesn’t have guidance on every single scenario out there. That’s impossible to do anyways,” said Chad Wetzel, a senior epidemiologist that analyzes contact tracing data. “So it’s a challenge for public health and professionals to provide accurate and good recommendations because every situation is so different.”

Though their schedule is regimented, nothing about tracking COVID-19 is routine. The team learns new information daily about the virus from the Centers for Disease Control and Prevention. Until two weeks ago, many stocked up on Clorox wipes to sanitize doorknobs and countertops. Now we know the risk of spread from surfaces is low.

There’s also new hires to train. The team, which includes health inspectors, nursing students and others, undergo a full day of training on the latest information about COVID-19 as well as shadow another employee. There’s a lot more to it, both institutional knowledge and quick thinking, than just calling someone on the phone.

“It doesn’t lead to trust if you call someone and read them a survey,” Heinz said. “It’s so much better if you can call someone and have a conversation.”

After a sample is collected and tested for COVID-19, the results go to the county health department where epidemiologists review their veracity. Team leaders then assign confirmed positive cases to one of the team’s contact tracers.

Typically individual contact tracers in Douglas County will call four people a day, depending on how many new cases there are. If the person doesn’t answer, they call back three times a day for multiple days before considering the case lost.

Once they reach someone, contract tracers say they’re calling because the person has tested positive for COVID-19. They educate them about the virus, what precautions to take and answer questions.

For the actual contact tracing work, they ask a series of questions including:

“Have you experienced any symptoms?”

“When did that start?”

“What symptoms have you experienced?”

“Have you been to the hospital?”

“Do you have any underlying health conditions?”

“Where do you work?”

“Where do you live?”

“How would you define your race?”

But often employees need to trust their own judgment to unearth detailed information about memories the person probably catalogued as mundane. Calls can take anywhere from a few minutes to a few hours.

The call can also take longer if the infected person does not speak English as their first language. It’s a problem prevalent among meatpacking workers and the Latino dominated South Omaha which have both been hit harder by the virus than any other occupation or geographic area. Some of the county’s team speaks Spanish, but otherwise the contact tracers dial into a third-party translation service, doubling the time of a call.

The ultimate goal is to build a knowledge base that comprehensively shows where COVID-19 was, is and how it moves. If epidemiologists can do that to the best of their abilities, it’s a direct contactthey know where the virus came from. But 44% of cases still result from community spread, a shapeless transmission that can’t be tracked or followed because they can’t find it.

“Is it perfect? No,” Frederick said. “Not by any means. Who would have predicted a pandemic like this. Things are constantly evolving.”

The county had to update its contact tracing system multiple times. Previously it relied solely on the Nebraska Electronic Disease Surveillance System, but the surveillance tool wasn’t designed for tracking something like COVID-19. The county ran into problems uploading data, modifying criteria they wanted to track and onboarding new public health employees, most of which work remotely where accessing the system becomes clunkier. 

Douglas County’s COVID-19 dashboard.

They needed a process that moved faster.

Since then the county’s added a CDC system and another called Red Cap. But these are changes that usually happen over months or years. Now they’re happening in weeks or less, posing challenges to a codrie of new public health employees and the epidemiologists leading them.

“We can look back two months from now and say how many cases did we not get reported electronically?” said Wetzel. “Or how many cases did we miss and didn’t end up calling due to any technology problem?”

So far Douglas County has fared well nationwide. Of 170 counties, states and cities compiled by the Solutions Journalism Network, it ranked near the top for gathering complete race and ethnicity data on each case, a likely detail to go unreported.

And while standards vary for what’s an adequate number of contact tracers, Douglas County has 15 per 100,000 people, the recommended standard by the National Association of County and City Health Officials. Johns Hopkins University says it should be double that.

But despite the discrepancies, an NPR investigation in early May showed Nebraska was one of eight states that could reach that goal. Wetzel said cases would probably need to double before they increase staff, but even that’s not guaranteed.

“It’s really difficult to predict, and I think that’s probably the concern across the country,” Wetzel said. “We have no idea if this is just going to be an uptick of if it’s going to be a huge surge.” 

Reopening and the Unknown

Across the state, cases have been on a downward trend but some worry what effects they’ll see from reopening businesses and recent protests.

Like most things with COVID-19, it’s a game of wait and see.

Because COVID-19 takes up to 14 days to show symptoms, the department can only prepare and hope that people continue wearing masks and practicing social distancing when possible.

“As you open up, cases are going to go up to at least some degree,” Wetzel said. “It’s where all those little things kind of add up to each other. If you’ve got a laboratory problem, if you’ve got an investigation or follow up problem with contact tracers, on top of it you have a problem with individuals in the public who may not be following recommendations. All of those kind of add up together and can cause some problems.”

Lindsay Hegeman does her own contact tracing inside Children’s Hospital and Medical Center as an Infection Preventionist. She feels confident cases will continue trending downward. They’re currently scheduling more in-person visits, elective surgeries and getting the hospital back to running at full capacity. And even if cases do increase, Hegeman says she feels confident in being able to isolate and contain the virus, as well as uphold rigorous sanitation practices. 

But even under all that confidence COVID-19 is hard to pin down.

“I still feel like we’re one day at a time,” Hegeman said.

The decision to reopen businesses has been controversial since May when Gov. Pete Ricketts announced restaurants, salons and other businesses could operate with some restrictions with more following on June 1.

At one point, the Institute for Health Metrics and Evaluation at the University of Washington projected Nebraska shouldn’t ease social distancing until July 8, the second-to-last state on the list. But reopening still needs to be a tiered system, said Theo Vos, a professor of health metrics at the institute.

“Where is the time period that you can start thinking about lifting some of your restrictions, say opening businesses?” he asked. “When can you take off the stay at home orders? When can you open schools?”

Projected social distancing timeline as well changes in mobility from the Institute for Health Metrics and Evaluation.

Dr. Jeffry Gold, Chancellor of the University of Nebraska Medical Center and chair of Nebraska Medicine’s Board of Directors, said if public health led the discussion, the country wouldn’t reopen until there was a vaccine. But there are other factors to consider.

“I don’t look at the amount of of domestic violence that’s coming from this, child abuse,” Gold said. “I don’t look at the amount of street crime, I don’t look at the amount of homelessness I don’t look at the amount of food insecurity that’s going on. These are all the dramatic sequelae of both the economic and the sociologic impact of this pandemic and the rate we reopen has to weigh all those things.”

Imperfect, but Human

Despite what the future may hold, the daily clockwork of contact tracers doesn’t stop. Heinz wakes each morning, checks e-mails as steam billows from her coffee before joining meetings and picking up the phone to continue inching toward a better understanding of the pandemic in Omaha.

It’s exhausting work. After months of trying to taper the tidal wave of COVID-19 information and anxiety coming at them, the trickle of new cases and questions never stops.

But there’s comfort in knowing that contract tracers are the first ones who can react to emerging trends and make a direct impact.

What keeps Heinz going is the personal connection’s she’s able to form over the phone.

Heinz has sat through some tearful phone calls as people ask how they’ll keep their families safe. There’s comfort in a human providing that information in an empathetic way.

And sometimes between her work, she’ll catch a news story about a COVID-19 recovery and recognize the name of someone she called. Seeing that person’s progress and knowing they made it out OK, it motivates Heinz to keep going too.

“We step into someone’s lives for 30 minutes and then you don’t get any follow ups,” she said. “Did they recover? Are they doing OK? Did they get out of the hospital? It’s truly rewarding when you can see things did turn out OK.”


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