contact tracin


An illustration from a brochure on contact tracing produced by the Centers for Disease Control and Prevention.

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New York City has largely relied on social distancing measures to control the spread of the coronavirus so far. Once New Yorkers in non-essential sectors return to their jobs, the city will need another way to control the spread of the virus, especially without a vaccine or proven treatment available. That’s why public health experts say contact tracing is the next step. 

On Monday, Mayor Bill de Blasio announced the city is hiring 1,000 people to conduct contact tracing. The NYC Department of Health and Mental Hygiene will supervise the tracers once the agency’s non-profit partner, the Fund for Public Health in New York City, screens and hires this new workforce. 

For contact tracing to work well, New York City officials will have to start educating people on this concept. 

A four-step process

Four steps make up the basis of contact tracing: Identify all cases of the disease as people contract it. Interview the person who is ill to figure out any contacts who were potentially exposed to the disease. Contact the people you think might have been exposed. Communicate with the person who is ill and their contacts to ensure they know how to address the disease and understand what they must do to prevent the disease from spreading further.

New Yorkers will have to learn these basics, even if they don’t apply to become contact tracers themselves. “In addition to the individual skills that [contact tracers] are going to need to display, it needs to be complemented with a lot of public messaging so that people are aware that they may be getting a phone call from the health department,” explains Dr. Adam Karpati, the senior vice president of public health programs at Vital Strategies who also spent 14 years working for the city’s Department of Health and Mental Hygiene. “Just that is a challenge, right? The idea that the health department is going to reach out to people over the telephone.”

Contact tracing is a key tool that public health professionals have used to combat the spread of diseases like HIV, tuberculosis, and measles in recent years. The basic steps aren’t new. 

However, applying contact tracing to the coronavirus crisis in New York City and elsewhere in the U.S. does bring new challenges. Contact tracing is most effective when the method matches the scale and pace required to control the spread of the particular disease. For controlling the coronavirus spread in New York City, that means contact tracing must be on a scale never attempted before at a pace that’s much quicker than what’s required for other diseases.

It will be a tremendous undertaking, but Karpati says we have good reason to believe scaling up contact tracing quickly and effectively in New York City is possible.

“Yes, it’s going to be moving fast, but this is a unique moment,” says Karpati. “Because the stakes are very high in terms of the potential value of [contact tracing], that is pushing the public health community to do it quickly and very responsively.”

Why now?

For weeks, health officials had to help people understand what to do if they thought they might have the virus. With limited tests available and hospital resources stretched thin, healthcare professionals and government officials in New York had to strike a delicate balance between identifying COVID-19 cases and preserving precious medical resources for people who needed them to survival. Hence the messaging early on that discouraged people who were not very sick to avoid coming in for testing.

During Monday’s contact tracing announcement, de Blasio touched on how this balancing act had been the central focus for weeks.

“When we were tragically seeing the disease spread and spread … we were trying to save lives, protect hospitals, deal with the most basic needs of people,” he said, “but we couldn’t build a whole contact tracing network that we wanted for something of this size.” 

Last week, Gov. Cuomo previewed New York state’s efforts on contact tracing, announcing partnerships with Bloomberg Philanthropies and Johns Hopkins University. He laid out why now is the time to dedicate particular attention toward ramping up contact tracing.

“The numbers indicate we are past the apex of this pandemic, and while we start our work to re-open our economy we must ensure we are doing it in a way that … does not undo all of the work and sacrifice it has taken to get here,” Cuomo said. “One of the most critical pieces of getting to a new normal is to ramp up testing, but states have a second big task–to put together an army of people to trace each person who tested positive, find out who they contacted and then isolate those people.”

Dr. Crystal Watson from the Johns Hopkins Bloomberg School of Public Health told reporters on Thursday that one of the things New York needs to do “before we can get to phase two where we gradually start lifting social distancing measures safely” is “scale up our public health workforce in order to identify cases and trace the contacts of each case.” 

The  idea is that if tracers can track down the contacts of someone with COVID-19, they can instruct all of those people who potentially contracted the virus to isolate. The contact tracers will be responsible for communicating with these contacts and connecting them with whatever they need (emergency food, a place to isolate without infecting others, etc.) so they can safely isolate and prevent themselves from infecting others. Contact tracing can also help health officials better predict where the coronavirus is spreading because they will likely have more precise data about COVID-19 cases.

Addressing privacy issues

What contact tracing will look like in New York City is still in flux. When asked about how New York City will coordinate its contact tracing with the efforts of the state government and other nearby states like New Jersey and Connecticut, a representative for the NYC Department of Health and Mental Hygiene said, “The precise structure, division of responsibilities and how all these pieces will support each other is still developing and will change with the outbreak.”

The limited emphasis on contact tracing in information from official government sources during March and most of April has contributed to uncertainty about how privacy issues will be handled. 

In March, for example, Singapore announced it would make the technology behind its TraceTogether app freely available to developers. Media coverage of TraceTogether often identified the technology as a “contact tracing app.” That raised privacy concerns. Although health officials in Singapore said the TraceTogether app does not record personal details like the user name or phone location data, the data logs stored in encrypted form can be decrypted. In South Korea, the government sent emergency alerts to the cell phones of anyone who had been in proximity to someone who tested positive for COVID-19. And, BBC News reported in March that people in South Korea could still identify some coronavirus patients from the alerts, despite the omission of names and addresses. These alerts included details as specific as a patient contracting the coronavirus from the instructor of a sexual harassment class he attended in a particular district. These alerts weren’t only available to the people who had been nearby; you could find this information on a government website. 

Karpati points out, however, that the privacy concerns associated with technologies like TraceTogether tend to center on features that have to do with proximity tracing. Proximity tracing can involve using the Bluetooth signals to identify people who were within a short distance of someone who contracted the coronavirus. 

While public health experts agree that contact tracing will be an essential part of reopening non-essential businesses and resumings gatherings throughout New York City, proximity tracing likely won’t be a part of the approach in the United States, especially not right away. For one, Dr. Karpati notes that proximity tracing may have potential, but almost everyone would have to use the technology for it to work because the whole method requires recording instances of two devices near each other. On top of the herculean task of ensuring widespread adoption, there would be major issues that would have to be resolved about how to protect patients’ confidentiality. And one of the core principles of contact tracing, says Karpati, is confidentiality. 

The representative for NYC Department of Health and Hygiene agreed, “Privacy is a pillar of contact tracing … Our disease control work, including contact tracing, is grounded in protecting patient confidentiality.” She also noted that the agency remains committed to confidentiality practices as they “scale up this initiative and design associated data systems.”

For example, when a contact tracer has to notify someone they were in contact with a coronavirus patient, they won’t reveal the name of the person who tested positive or give identifying details that could compromise anonymity. When contact tracing functions correctly, the contact tracer would have a list of contacts that’s comprehensive, which they discern from interviews with COVID-19 patients. Then, assuming the contact tracer is successful, New Yorkers would be notified quickly if they’ve been in contact with a patient. Keeping identifying information confidential would ideally build more trust in the contact tracing system. 

Unless the government is willing to enforce compliance with the contact tracers’ instructions, building trust is one of the best and only ways to get people to follow through with their contact tracer’s quarantine recommendation. 

The role of tech

The NYC Health Department’s representative said they plan to build on their existing infrastructure that they already use in contract tracing for diseases like tuberculosis and HIV. The process of adapting and scaling up the technology the agency uses is currently in development. Although it isn’t out of the question for New York City to incorporate an app or another tech tool intended for public use into their approach going forward, there haven’t yet been any announcements or other indications of a plan to develop an app or adopt something similar. 

Since contact tracers in New York City will be working remotely, they will get phones and laptops to conduct their work. Ultimately, Karpati emphasizes, the role of technology within contact tracing is to “enable and support this very human, intimate process” of engaging with coronavirus patients and their contacts.

Should all New Yorkers expect to be involved in contact tracing in some shape or form? On Thursday, Emily S. Gurley, an infectious disease epidemiologist at the Bloomberg School of Public Health who is leading the effort to build an online curriculum for contact tracers in New York state, said that “the simple answer is, yes.”

Gurley said, “That’s because any of us could be exposed to someone who has COVID-19, many of us already have. Our ability to stop this disease and stop transmission requires all of us to cooperate together.”

Nicole Javorsky is a Report for America corps member.