The head of the U.S. Centers for Disease Control and Prevention, Robert Redfield, says contact tracing will be vital in the next phase of the coronavirus pandemic in the United States.
Poor countries have advice to offer.
Contact tracing is used all over the world, including in the U.S. The idea is to track down anyone in recent contact with a newly diagnosed patient, then monitor the health of these contacts. In the developing world, it's been a valuable tool in fighting infectious diseases like Ebola and tuberculosis. Public health workers there have lots of experience.
So as the U.S. hires potentially hundreds of thousands of contact tracers to contain the coronavirus, health departments could be looking to models from such regions as Africa, South Asia and Latin America on how these teams will do their work.
Partners in Health, which is known for its work in Haiti, Rwanda and Peru, is helping to set up a coronavirus contact tracing program in Massachusetts.
In West Africa contact tracing was crucial in bringing the 2014-2015 Ebola outbreak to a close.
Raj Panjabi's organization Last Mile Health helped set up contact tracing teams in Liberia during that crisis.
"We couldn't break the chain of transmission and drive the epidemic down to zero cases in Liberia without contact tracing," says Panjabi, a physician at Harvard Medical School and Brigham and Women's Hospital.
In the remote part of Liberia where Panjabi's group was working, contact tracers were hired to investigate each Ebola case and track down all the "contacts" of those diagnosed cases.
To get Ebola you have to have close physical contact with the infected person or their bodily fluids so the overall number of at-risk contacts was far lower than with COVID-19. Panjabi said it was about 10 people for each Ebola patient.
"The contact tracers got hired and chosen from within the community," says Panjabi — and that kind of community knowledge offers a tremendous advantage. "They'd locate the listed contact because they know the community. They have trust with the community," he says. "And they'd identify any additional contacts who meet that definition of exposure that were missed in the initial investigation."
Panjabi says having social connections and being good with people is more important in this job than a medical degree. Most of the people doing this work for Last Mile Health were not medical professionals, but the teams reported to nurses and public health officials who were. Each contact tracer visited their list of contacts twice a day.
"Morning and afternoon throughout the 21 days post-exposure period," he says. Ebola has a 21-day incubation period compared to 14 days for the new coronavirus. The contact tracers would take the person's temperature and check if they had any other symptoms of Ebola.
If they did have symptoms, the contact tracer quickly arranged to move the patient to a treatment center. This had two primary benefits. First, Ebola patients are far more likely to survive if they're treated early. And second, transferring them to a treatment center got that infected person out of the community, isolated them and made it far less likely they'd spread the virus further.
Panjabi says the quality of the contact tracing is crucial. The health workers need to find every contact who may have been exposed and monitor them closely.
"And if you do that right, that strategy will eventually extinguish all transmission lines and an epidemic," he says. "In Liberia, that was exactly the practice that led to the last [Ebola] case being identified. And then the epidemic halted."
India serves as another instructive example. With 2.7 million cases of TB last year, contact tracing is the bread and butter of TB control.
Shelly Batra is cofounder of a group called Operation Asha that before COVID-19 had been sending contact tracers door-to-door to track down people with TB, counsel patients and monitor them as they take their medications.
"Now all these activities have come to a halt because the government is talking of social distancing, 'stay at home'. No movement in the field at all," she says. India is under a strict nationwide lockdown to prevent the spread of the coronavirus, forcing Batra's health workers to monitor tuberculosis patients via cellphone.
"Phones are ubiquitous. In India people say there are more phones than toilets," she says."That's what is really working for us."
Her contact tracers now cajole TB patients into taking their daily medicines over the phone.
"So here's what our health workers are doing," she says. "Suppose they give medicines for a week on Sunday. Monday morning they'll call up after breakfast, 'Hey, guy, you had your breakfast. Have you had your meds or not?' If he says no, 'Why not?' "
Now Operation Asha has also started to screen patients for COVID-19 over the phone. The health workers have a questionnaire on a tablet and can ask a potential contact a series of questions to determine if that person should be referred to a clinic for testing.
Batra says at a time when people are out of work, this new work on the coronavirus is providing jobs that can be done from home.
"And there is no requirement for any degree at all if you are able to read or write a little bit," she says. "There are so many people who want jobs right now. So many people would be willing to come forward. They are doing something good. They're serving the community. And they will get a little payment for it."
As the U.S. looks to contain the coronavirus so that the economy can start to reopen, Raj Panjabi says contact tracing could be a win-win.
"If we're going to be successful in achieving viral suppression in the United States and maintaining viral suppression so that we can reopen the economy, where are the hundreds of thousands of American [contact tracers] going to come from?" Panjabi asks. "One possible way is to actually hire Americans who've been unemployed by this pandemic and put them to work."