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This scanning electron microscope image shows particles of the virus SARS-CoV-2 (round magenta objects) emerging from the surface of cells cultured in the lab. SARS-CoV-2 is the scientific name of the virus that causes COVID-19. The virus shown was isolated from a patient in the United States. (Provided by the National Institute of Allergy and Infectious Diseases's Rocky Mountain Laboratories in Montana)

When reports of coronavirus outbreaks tied to parties on Boulder’s University Hill first began filtering into Carol Helwig’s office at Boulder County Public Health, she and the rest of the staff were faced with a disease-tracking nightmare.

Dozens of young people had attended the gatherings. Many didn’t know one another. And, when the parties stopped, they mostly went their separate ways. How on Earth were public health workers going to find them?


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And thus began a case study in disease contact tracing for the modern world. Helwig, who is Boulder County Public Health’s communicable disease program manager, and other officials started by trying to figure out who organized the parties. They then asked for group texts, email chains, social media responses — anything that might help them identify people who had been at the parties and may have been exposed to the virus.

They chased those leads and turned up more texts, more names. Officials reached out to hundreds of people, telling them that they should go get a coronavirus test and self-quarantine for 14 days. And what had been an exploding number of COVID-19 cases in Boulder County has now declined, something Helwig credits to the contact-tracing work.

“It’s one of the only effective prevention methods that we have in the absence of a vaccine,” she said. “So we do hope that the public recognizes the value and supports our case investigation and contact tracing activities.”

A red Solo cup in Boulder. (Provided by CBS4)

Now, as cases of COVID-19 rise in Colorado, contact-tracing efforts are ramping up statewide to meet the demand. So far, public health agencies across the state say they are keeping up. But they are also planning for how to handle the higher and more complex caseloads they expect will be coming in the future.

“What we’re seeing is that we might need to beef up our messaging to the public with a media campaign, to really help the public understand how important the contact tracing is,” said Cali Zimmerman, the emergency management coordinator for the Denver Department of Public Health and Environment.

Old idea, new methods

Contact tracing is an age-old epidemiology tool where health workers chase a disease’s footprints to catch infected people before they infect others. But, in the time of COVID-19, it has taken on new challenges.

With contact-tracers largely confined to their homes to avoid exposing themselves to the virus, much of the work is taking place over the phone. In an interview with CNN last month, Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, said contact tracing by telephone hinders its efficacy.

“I don’t think we’re doing very well,” he said.

“If you go into the community and call up and say, ‘how’s the contact tracing going?’ the dots are not connected because a lot of it is done by phone,” Fauci added. “You make a contact, 50% of the people, because you’re coming from an authority, don’t even want to talk to you.”

Authorities in Colorado said they are having better success.

Sarah Tuneberg, the leader of the state’s coronavirus Innovation Response Team, said 78% of people who have tested positive for COVID-19 in Colorado have made contact with a public health professional. But she said the state doesn’t have comprehensive data on how many people are cooperating with those workers in contact-tracing efforts. In general, she said, “Coloradans are being incredibly collaborative.”

“They’re answering the calls; they’re providing good information,” she said.

That matches what local public health agencies say they have seen.

In Alamosa County, deputy public health director Jordan Kemp said his agency is able to reach people infected with the coronavirus and their contacts within 24 hours most of the time. Of the more than 200 positive cases in the county, Kemp said there’s been only one person public health workers were unable to reach.

Helwig, in Boulder, said her agency is investigating about 10 cases per day, with most of those infected willing to talk to health workers about where they’ve been and with whom they’ve been in contact. Zimmerman, in Denver, said her agency is investigating about 70 new cases a day, with about 70% of those providing information on people they had contact with while potentially infectious.

Lisa Straight, director of community health for the Denver Department of Public Health and Environment, talks with a community member about where to find resources related to the coronavirus outbreak. (Moe Clark, The Colorado Sun)

Zimmerman said some people have been wary about providing information to health workers. Some may just prefer to reach out to their contacts themselves, she said. And others may be suspicious because there have been scam phone calls going around from people posing as contact-tracers; real contact-tracers will never ask for your Social Security number or banking information, she said.

“I think once we get in touch with folks, it’s a great conversation,” she said.

Preparing for a surge

Everyone, though, is readying for an expected surge of cases — cases that, like the party-linked ones in Boulder, will be more complex than average.

When people were staying home much more, Helwig said contact tracing was fairly simple. Most of the contacts needing to be tracked down were in the infected person’s house. One health worker could wrap up both the interview with the infected person and give instructions to their contacts in a single phone call.

Now, as people move around more, tracing their contacts becomes even harder. Helwig said Boulder plans to soon split the work into two teams — the disease investigation team, which will interview infected people, ask them where they think they were exposed and where they went afterward, and the contact-tracing team, which will follow-up with those contacts, tell them to isolate and get tested and provide them with support resources if they need them.

“We’re really trying to prepare for higher numbers just based on what we’re seeing around the country,” Helwig said.

Shoppers maintain one-way traffic patterns at the Palisade Farmers’ Market in Palisade, Colo., Sunday, June 14, 2020. The weekly market runs every Sunday through Sept. 20. (Barton Glasser, Special to The Colorado Sun)

Zimmerman, in Denver, said increased mobility means that contact-tracers can’t anymore just reach out to individuals who may have been exposed.

“We’re really going to have to start looking at what places people have visited and notify those places as well,” she said. “So we expect contact tracing to expand in the coming weeks.”

An analysis published last month by researchers at the Colorado School of Public Health estimated that Colorado will need to add between 1,000 and 1,600 additional disease investigators and contact-tracers to meet the coming demand. So far, most agencies say they are handling that work largely in-house.

Denver and Boulder have trained workers with other public health duties — or even in entirely different departments — to conduct case investigation and contact tracing if need be. Kemp said Alamosa has also largely handled the workload with existing staff, though he said the department has also reached out to the Colorado Department of Public Health and Environment for help from time to time.

Tuneberg, with the state’s Innovation Response Team, said about 175 public health students have been trained to do contact-tracing work for CDPHE. And she said the state is also training about 100 people per week from AmeriCorps and Senior Corps to do the work.

All told, she said, CDPHE expects to have 800 to 1,000 people in place by the end of summer to conduct case investigation and contact tracing. Those workers will provide “surge capacity,” she said, helping out local public health departments when their staff is overwhelmed.

The goal is for Colorado to be able to investigate and contact-trace 500 new cases a day, Tuneberg said. Just a few weeks ago, that number was well off into the distance. But there were nearly 350 new cases reported to the state on Monday, and one day last week saw over 600 cases reported in a single day — the most since late-April.

Tuneberg, though, said contact tracing can’t fix Colorado’s rising number of cases all by itself. It’s also important to have adequate testing and to make sure people are supported so they can isolate or quarantine if needed. It’s important for workplaces and businesses to take precautions to prevent the spread of the virus. It’s important for people to wear masks.

“Contact tracing isn’t a solution independent of all the other pieces,” she said. “It’s part of a much broader strategy. And we have to get all of those pieces right.”

John Ingold is a co-founder of The Colorado Sun and a reporter currently specializing in health care coverage.

Born and raised in Colorado Springs, John spent 18 years working at The Denver Post. Prior to that, he held internships at the Rocky Ford Daily Gazette, the Colorado Springs Gazette and the Rocky Mountain News, among other publications. He also interned one summer in the public relations office at the Cheyenne Mountain Zoo, where he got to sit on an elephant's knee and get his photo taken.

John was part of The Denver Post's 2013 Pulitzer Prize-winning breaking news team for its coverage of a shooting at an Aurora movie theater, and, in 2015, he was a Pulitzer finalist for a series he wrote on parents whose children suffer from a rare form of epilepsy and the help they hoped to find through Colorado's medical marijuana system.

Email: Twitter: @johningold