What Is Contact Tracing?

covid-19 contact tracing

 Verywell / Julie Bang

When an infectious disease like COVID-19 is identified, one of the first and most important tasks is figuring out how it spreads. Once scientists have this information, they can dispatch public health teams to track a pathogen as it spreads through a community, country, and even the world.

People who contract SARS-CoV-2, the virus that causes COVID-19, can become seriously ill and pass on the infection. Perhaps of even greater concern is that someone can be infected by the virus and not feel sick, but still be able to pass the infection to other people. Those other people are called their “contacts.”

Public health teams are training "contact tracers" to find the contacts of people with confirmed cases of COVID-19.

Why This Matters

  • Contact tracers let contacts of people with COVID-19 know they might get sick.
  • Their work helps track the spread of a disease, including the location, speed, and infection rate.

What Do Contact Tracers Do?

Contact tracers are trained public health workers who use a combination of technological, scientific, and communication skills to track the spread of an infectious disease.

There are dedicated "disease detectives" who do this type of work in the U.S. even in non-pandemic times, including the 70 to 80 members of the Epidemic Intelligence Service within the Centers for Disease Control and Prevention (CDC). But COVID-19 has forced public health departments and organizations to mobilize more people for contact tracing. Johns Hopkins estimates 100,000 additional contact tracers are needed, which would require $3.6 billion in emergency government funding.

Contact tracers primarily gather information by identifying people who are confirmed to have an illness through medical records and healthcare databases, then reaching out to them, usually through a phone call. They'll then call anyone that person interacted with over the previous several days who might be at risk for getting sick too. They also ask when—if ever—a person began experiencing symptoms.

The data they gather helps organizations like the CDC determine the R0 (pronounced R-naught)—a value that shows how many people any given sick person with the disease is likely to infect over the course of their illness. Contact tracers can also help calculate how long an individual will need to stay isolated or quarantined. For COVID-19, that period of time is 14 days.

Recurring Check-Ins

Once contact tracers have identified the chain of people connected through their exposure to an infectious disease, they will stay in touch with these people for days, if not weeks, as they track the spread of the illness through the community.

These check-ins will continue until each person on their list has either:

  • Become ill and recovered
  • Stayed healthy through the period during which they could get sick (incubation period)
  • Passed the period during which they could spread the infection to others (contagious period)

Support and Education

Contact tracers and other public health professionals provide an essential service in the form of education. When a contact tracer first talks to someone who has been diagnosed with COVID-19, or a contact who has been exposed, they explain how the virus is spread, why it’s important to “flatten the curve,” and how each one of us can safely support the goal of lowering infection rates.

They’ll stay in touch with all of these people, usually checking in at least once a day for several weeks. During each conversation, a contact tracer will ask if the person feels sick, or if they’re feeling better if they are sick. They also ask about the person’s general needs, including medical care, social support, and basic essentials like housing.

It’s the job of a contact tracer, and the public health system at large, to ensure that access to care for COVID-19 is equitable. That means that everyone can get the help they need regardless of race, economic standing, educational background, or any other demographic factor. When appropriate, contact tracers will connect people to social services and clinical care centers.

Why Contact Tracing Is Important

The name might seem self-explanatory, but contact tracers actually do more than just find people who might have come into contact with someone who is infected with COVID-19.

In fact, one of the most important things contact tracers do is determine if someone is in a vulnerable population. If someone is in a vulnerable population, it means they lack the support and resources they need to take precautions to stay healthy, self-isolate, or get treatment.

Who May Be In a Vulnerable Population?

  • A person who will lose their job if they don’t show up for work is likely to keep working even if they get sick. Not only will this impact their health, but it could allow the virus to be spread to others.
  • A person without caregiving help to look after their children or another family member that they are responsible for is less likely to separate themselves from others (isolate) if they get sick. They may even care for others while they are sick or during the period that they are contagious.
  • A person who needs mental health support to safely follow recommendations to isolate or quarantine. Mental health support is important in any time of crisis, but especially important when people are going to spend a lot of time alone.
  • People who are homeless are also considered part of a vulnerable population. Homelessness does not always mean a person lives on the street. Many people who are homeless live in shelters or share close spaces with others. In some cases, these spaces might be confined, have little to no hygiene, and lack running water. All of these factors increase the likelihood of an infectious illness spreading.

Privacy and Confidentiality

When contact tracers call people to let them know they have been exposed to COVID-19, they do not disclose specifics, such as the name of the person who may have infected them or where they live.

If you test positive for COVID-19, a contact tracer will ask you for a list of people you have been in close contact with recently, as well as a way to get in touch with them (usually their phone number).

When the contact tracer calls your friends, coworkers, or any other people you have spent time with, they will not reveal that you are positive for COVID-19. 

Any information that contact tracers find out about a person is confidential. They are not allowed to share this private information with anyone except their supervisor and people on public health teams who are considered “need to know.” Even so, there are some specifics that they don’t need to pass on.


Imagine that you are a contact tracer who has called a man named David. You are calling him to let him know he has been in contact with someone who tested positive for COVID-19. You ask David about who he lives with and who he has spent time with recently. David lives alone but works at a laundromat in the city.

When you tell David that he will need to isolate himself and not go to work until the contagious period has passed, he tells you that he can’t stop working. You offer to provide a letter he can give to his employer, but he refuses and confides that he is undocumented.

As a contact tracer, you can inform your supervisor on the public health team that David is in a vulnerable population; he needs support and resources to isolate and not risk losing his job. You do not, however, have to include that he is undocumented, because this information isn’t relevant.  

Another example scenario that contact tracers might encounter is a contact who is cheating on their spouse. Imagine that you have placed a call to a young woman named Jennifer who has tested positive for COVID-19.

You ask who she has been in contact with recently and she states that she has not been to work since the day before yesterday because she was feeling sick. Her husband is at home with her, but he’s not having symptoms. You ask Jennifer if she saw anyone else the day or two before she got sick. Jennifer confides in you that she did spend time with another partner who she has been seeing, but that her husband does not know about.

You will need to inform this person that they are a contact of someone who tested positive for COVID-19 so they can take precautions and isolate, but you do not need to do anything more with the information Jennifer has given you. The type of relationship Jennifer had with each person she came in contact with during the period when she could have spread the virus does not matter.

How to Become a Contact Tracer

In response to the COVID-19 pandemic, there is an urgent and global need for contact tracers. The role employs a specific set of skills, but many of them can be learned. You can take online courses in contact tracing through universities like Johns Hopkins (this course can be audited for free on Coursera).

Many companies, governments, and municipalities that are hiring contact tracers will provide training. CONTRACE Public Health Corps will pre-screen individuals interested in contact tracing and connect them with organizations that are hiring.

If you have a background in health care, statistics, public health, or even experience working in a call center, you likely already have many of the skills a contact tracer needs to be successful.

Many contact tracer jobs are completely remote, contributing to the efforts of slowing the spread of COVID-19 through social distancing. While some contact tracers (usually those with a public health degree) are required to go out in public to locate hard-to-find contacts, most people connect with contacts remotely.

The work is full-time and earns between $17 and $22 per hour.

How the Job Works

In the U.S., medical records and other healthcare databases are used to identify people who have tested positive for COVID-19. From there, contract tracers can make phone calls to these individuals and their contacts.

In some places in the world, apps are also being used to make follow-ups and check-ins easier. People can self-report symptoms each day, and that information is stored in a central database.

While contact tracers can often work from home as long as they have reliable, secure internet and phone service, they may be required to take additional steps to ensure the information they access and obtain remains secure. For example, they may need special access codes or VPNs on any computers used to conduct their work.

If you want to learn more about becoming a contact tracer, the first place to check is your local or state health department.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention (CDC). How to Protect Yourself & Others.

  2. World Health Organization (WHO). Contact tracing.

  3. Watson C, Cicero A, Blumenstock J, Fraser M. A National Plan to Enable Comprehensive COVID-19 Case Finding and Contact Tracing in the US. Johns Hopkins Bloomberg School of Public Health.

  4. Delamater PL, Street EJ, Leslie TF, Yang YT, Jacobsen KH. Complexity of the Basic Reproduction Number (R0)Emerg Infect Dis. 25(1):1‐4. doi:10.3201/eid2501.171901

  5. Centers for Disease Control and Prevention (CDC). Contact Tracing : Part of a Multipronged Approach to Fight the COVID-19 Pandemic.

  6. Centers for Disease Control and Prevention (CDC). Interim Guidance on Unsheltered Homelessness and Coronavirus Disease 2019 (COVID-19) for Homeless Service Providers and Local Officials. Centers for Disease Control and Prevention.

  7. U.S. Department of Health & Human Services. Your rights under HIPAA.

  8. Coursera. Johns Hopkins University. COVID-19 Contact Tracing.

  9. Contrace. Contact Tracing: How It Works.

  10. Centers for Disease Control and Prevention (CDC). List Requirements for Protecting Health Information.

By Abby Norman
Abby Norman is a freelance science writer and medical editor. She is also the author of "Ask Me About My Uterus: A Quest to Make Doctors Believe in Women's Pain."