In the world of public health, contract tracing is one of our best tools for combating epidemics — and it’s far from a new concept. By identifying everyone who’s come in contact with someone infected with a disease, we’ve been able to reduce sexually transmitted infections like HIV and fast-moving contagions, such as Ebola during Liberia’s 2014–2015 epidemic.
Across the country and the world, cities and health departments are now ramping up their contact tracing programs in order to contain COVID-19. It’s not an easy or a small task: New York City has hired nearly 2,000 “disease detectives” for its program. Experts say that more than 300,00 people may be needed in the US to conduct contact tracing as the coronavirus pandemic continues.
Tracking down people who may have been exposed to someone who’s tested positive for COVID-19 isn’t just about keeping that person safe. Data suggest a COVID carrier will infect two to three other people, on average, which means it’s important to compile lists of who should get tested after exposure. One study in Shenzhen, China, showed contact tracing and isolation of sick patients helped reduce community infection of COVID-19.
“Contact tracing is a tried and true tool,” says Dr. Umair Shah, executive director of Houston’s Harris County Public Health, where officials added 300 contact tracers at the end of May. That said, he adds, it’s “a labor-intensive and a time-consuming process.”
Here’s what to know about the process of contact tracing, and how you can help speed it up, if need be.
What’s the first step in contact tracing?
If you’ve tested positive for COVID-19, your positive test result will be passed on to your local health department, no matter where you get tested. Shah and his team get positive results daily from local hospitals, private labs and community testing sites, plus his department’s own testing sites. “It’s chaotic,” he says. His team might receive just a name and a date of birth, or a name and gender. Information is inconsistent and may not come with contact details like a phone number. It’s the contact tracer’s job to track down the person behind the positive COVID case.
Who will get in touch with you, and how?
Typically, an epidemiologist or senior contact tracer reaches out to the positive COVID patient. The purpose of the call is twofold: to educate the infected person about the coronavirus and precautions they need to take, and to find out who they’ve been in contact with and may have gotten sick.
You might be asked questions like where you ate lunch, how you got there, if you have a dog and, if so, where you’ve walked your dog.
That conversation might last anywhere from 60 to 90 minutes. Harris County’s newly hired contact tracers include both paid workers and volunteers, from public health and medical school students to retired residents to people who are out of work because of the pandemic. In New York, out-of-work librarians have come on as contact tracers.
“There are a lot of people that want to give back and help with this public health mission,” Shah says.
When a contact tracer reaches out, your caller ID might show the call is coming from your county or city health department, but not necessarily. If you don’t pick up because you don’t recognize the number, the tracer will leave a message.
What kinds of questions will you need to answer?
The contact tracer will confirm the information they’ve gotten from the lab, like your name and date of birth. They want to make sure they’re talking to the right person, says Tashrik Ahmed, associate faculty member at the Johns Hopkins Bloomberg School of Public Health, and not divulging private health information to another household member. The tracer will then ask questions about your symptoms, when they started, when and where you first got sick, and if you’ve been hospitalized for COVID. The goal is to try to pinpoint the first day symptoms started. Then they’ll help you reconstruct everywhere you went in the prior two weeks and make a list of who you were in contact with.
“This is the most difficult part of the interview,” says Ahmed, “trying to remember where you went.”
You might be asked questions like where you ate lunch, how you got there, if you have a dog and, if so, where you’ve walked your dog. Contact tracers are most interested in “close contacts,” which are most commonly defined as someone you’ve been within six feet of for 20 minutes or longer.
“The usual suspects are housemates, coworkers in close proximity or anyone who joined you for a night out or a meal,” Ahmed says.
What happens next?
Typically, a junior contact tracer takes over, reaching out to those people on the positive case’s list. These calls start with the tracer confirming your identity. Then they’ll let you know you’ve potentially been exposed to the virus, but they won’t tell you who may have exposed you to COVID-19.
“Their biggest job is to give you information and resources on how to isolate yourself properly,” Ahmed says.
You’ll get basic information about the virus, and the tracer will ask if you’ve had any symptoms. If you have symptoms, you’ll be asked to self-isolate and get tested. If you don’t have any symptoms, the tracer will ask you to get tested and explain how to monitor symptoms by checking your temperature and watching for cough or shortness of breath. They’ll suggest that in the meantime, you diligently use a face mask and social distance. Close contacts should self-quarantine for two weeks.
If just one person the original case was in contact with ends up testing positive, then “that starts the whole cycle over again,” says Shah.
Contract tracers typically follow-up with the people they’ve called, but the frequency varies, Ahmed says. The gold-standard is to call and follow up once every day until the person is done with quarantine, he says, but given the scope of the pandemic, that’s not feasible. Most tracers are following up once or twice a week, but give contact information if you want to reach out yourself with questions.
For large venues the COVID-positive patient visited, tracers work directly with the venue to put out a notification to their patrons, and they might also help the business identify further contacts.
What kind of training do contact tracers get?
Many health departments are using a Johns Hopkins Coursera class on contact tracing to screen potential new tracers. The course includes basic information on the epidemiology of COVID-19 and an introduction to contact tracing.
People who pass the course and get hired then get additional in-person and online training on topics like how the disease spreads, the incubation period, ethics, HIPAA and customer service. In Harris County, new contact tracers shadow experienced ones.
What if you’re worried about sharing personal information?
A contact tracer will never ask you for sensitive personal information like your social security number, financial or banking information or your legal status.
Your identity and your health information are kept private and won’t be shared with anyone. Data is entered into a secure system and will only be used by your local and state health departments.
What else should you know about contact tracing?
With states reopening, some businesses might ask customers to provide information in case a contact tracer reaches out because of a confirmed case. For example, some restaurants are now asking customers to write their name in a log.
Tech companies are also working on contact-tracing platforms that could track whether a user was near someone who tested positive for COVID-19. Phone owners would have to individually download the app first.
Shah says that contact tracing is an important tool in helping contain COVID-19, but it’s not the only one. “We have to rely on our community for preventative measures,” he says, like mask-wearing and social distancing. “The best thing in the world is for our contact tracers and epidemiologists not to have a high workload because people in the community are heeding preventative measures.”