Disease detectives’ goal: Track, trace and test
Strategy to stop virus spread is key to safe reopening
Wanted: People with a talent for telling terrible news to total strangers.
As the economy reopens and people start venturing back out into the world, California’s counties are building an army of 20,000 “contact tracers” to find everyone who is unknowingly infected by the COVID-19 virus, preventing the ignition of deadly new clusters of disease.
The recruits — redeployed civil servants and volunteers across the state — will be trained as disease detectives, serving six- to 12-month-long gigs that demand skills ranging from data entry and psychology to project management and crisis intervention.
“Ultimately, it’s customer service,” said Contra Costa County Public Health Director Daniel Peddycord. “We need people with critical thinking skills and empathy.”
Contact tracing, combined with expanded testing, is a pillar of the state’s modified stayat-home order, Gov. Gavin Newsom announced Monday.
The goal is to track and trace every person in the state who may have been exposed, then quickly isolate and test them. Today, the new UC San Francisco Pandemic Workforce Training Academy, an $8.7 million partnership with the California Department of Public Health, will start online trainings in public health techniques.
If coronavirus flareups can be quickly extinguished, there’s no need to lock down the entire economy again.
Track, trace and test has long been part of the toolkit of local health departments in California. By identifying and isolating close contacts of infected individuals, officials have been able to stop the spread of diseases such as measles and tuberculosis. But in the early days of the pandemic, they lacked the manpower to catch every case — especially in Santa Clara County, which was hit early and hard.
“Contact tracing is a foundation of public health work,” said Dr. Nicholas Moss, acting director of Alameda County’s Public Health Department, which has expanded its staff of contact tracers from seven to 60 and plans to grow to 300.
Already, there has been an outpouring of response, said Bay Area health officers. And the effort is paying off: Current teams, while small, are catching silent infections, they said.
“It’s incredibly moving to hear all of the people in our community step forward and ask how they can help support these efforts,” said Moss.
No longer are we trying to stop the introduction of isolated cases from overseas, as in the early days of the pandemic.
Rather, we’re trying to extinguish the hundreds or thousands of communitybased viral sparks “rustling under the leaves,” said Harvard epidemiologist Michael Mina, that could ignite outbreaks so large that they would dwarf the first wave of the pandemic.
COVID-19 presents unique challenges for containment, said Dr. Mike Reid, a UCSF infectious disease expert who is leading efforts to train new contact tracers. That’s what makes early identification of infection so important.
“It spreads so rapidly,” he said. “And it can be spread before the appearance of symptoms.”
On laptops and phones, these experts seek to find everyone who has spent at least 10 minutes within 6 feet of a person who has tested positive for the virus — up to two days before that person felt sick.
Then they inform them of their risk, refer them to testing and urge them to stay isolated at home for 14 days.
Maybe it’s someone who helped unpack boxes in a grocery aisle or shared a coffee break during a shift at the local hardware store. Perhaps they were part of a team that laid irrigation pipes or hung drywall. They may have cooked church dinner or bathed an elder.
A county’s contact tracing squad — officially known as case investigators — gets a name and phone number for every person who has tested positive, either from their doctor or drive-thru public site.
During the call, the investigators ask where they have been and who they have been with in the days leading up to their illness.
The sleuthing then turns to potential contacts, narrowing down names and phone numbers.
The phone conversation, typically read from a script, starts formally: “You have been identified as a close contact to a person with a confirmed novel coronavirus infection,” they say. “We would like to ask you some questions since we think you may have been exposed to the virus.”
But it ends warmly, with offers of help — for food, housing, medicine, child care, elder care or any other needs. The county also is available to provide symptom “checkups,” via text, chat, email or phone.
“The responses range from tears to ‘I’m glad I know,’ ” said Peddycord of Contra Costa County, which is focusing its efforts on what’s called “SOS,” or sensitive occupations and settings, such as nursing homes. “Most people are grateful and reassured.”
Until now, contact tracing has been relatively easy, because most people have been stuck at home. They know who they’ve been with.
Each case typically has only three or four “contacts,” on average, said UCSF’s Reid. With 40 new daily cases, San Francisco has 120 to 160 people to track down every day.
If a sick person lives or works in a group setting, like a nursing home, it’s straightforward to obtain a list of their contacts.
But as people return to their jobs, the effort will become much more complicated. People may not know who’ve they’ve seen or how to reach them. On Tuesday, Santa Clara County Health Officer Dr. Sara Cody estimated the average number of contacts, per case, could jump to 40.
“It is a very, very large body of work,” she told the county board of supervisors on Tuesday.
To find people, “It is a bit of ‘hunt and peck’ to get ahold of folks and who they’ve been around,” said Peddycord. His team will call three to five times, then deliver a letter. “That is the ugly nuts and bolts of this.”
People are under no legal requirement to disclose where they’ve been or who they’ve been with.
The tracers won’t disclose names. They also won’t ask for immigration status, health coverage, Social Security number or bank account information.
“First and foremost we want to protect privacy,” said Moss. “The most important thing is to be able to build trust.”
It will be increasingly important to test people who feel fine — people who are infectious despite showing no symptoms — to stop the virus before it spreads, said Peddycord. Workplaces are potential hot spots of new outbreaks, he predicts.
Contacts may not have enough food and supplies to undergo 14 days of quarantine, especially if they’re living paycheck to paycheck. So contact tracers provide information about health and social services while navigating cultural and language barriers. In San Francisco, the Hispanic and Latinx communities are being affected disproportionately.
“I talked to a man that works in a food packaging plant with 200 other people, and I was asking him to stay home for 14 days, even though he felt fine, and forgo a paycheck,” said Susie Welty, a UCSF public health expert who’s doing contact tracing.
New technologies can help tracers with their jobs. The UCSF and San Francisco partnership relies on a contact-tracing app by software company Dimagi. Last week, Apple and Google released details about how they will build Bluetoothbased functionality into their mobile operating systems to alert users in the event of contact with someone who’s COVID-19-positive. Given privacy concerns about this technology, tracking will be done anonymously and will also require opt-in.
There also have been development efforts led by academic groups, such as the mobile app “Covid Watch,” a joint effort between researchers at Stanford University and the University of Waterloo in Canada, which allows users to anonymously log their contacts with other app users through Bluetooth.
Without a sudden adoption of apps to aid contact tracing, the skills of traditional contact tracers remains central to the state’s reopening success, said health directors.
“Compassion, curiosity and some competence with technology,” said UCSF’s Reid. “Those are the skills that count the most.”