Contact Tracing: Frequently Asked Questions

Contact Tracing: Frequently Asked Questions

Information for Health Departments

Updated Oct. 21, 2020

Learn about the basics of contact tracing and digital tools used for contact tracing.


illustration of a woman surrounded by a network of people
What is the difference between case investigation and contact tracing?
  • Case investigation: Case investigation is the identification and investigation of patients with confirmed and probable diagnoses of COVID-19. During the case investigation, the health department works with a patient who has COVID-19 to help them recall everyone they had close contact with during the time when they may have been infectious. For COVID-19, a close contact is anyone who was within 6 feet of an infected person for a total of 15 minutes. An infected person can spread COVID-19 starting 48 hours (or 2 days) before the person has any symptoms or tests positive for COVID-19.
  • Contact tracing: Contact tracing is the subsequent identification, monitoring, and support of a confirmed or probable case’s close contacts who have been exposed to, and possibly infected with, the virus. The infected patient’s identity is not discussed with contacts, even if asked.
What guidance and materials are available for health departments to help with contact tracing?

CDC has developed a range of guidance documents, training products, communications toolkit, fact sheets, guides and tools, and resources for contact tracing and communications resources.

Visit CDC’s Contact Tracing Resources webpage to access all of CDC’s resources for conducting contact tracing to stop the spread of COVID-19.

What is CDC’s role in contact tracing?

CDC provides guidance and support to help State, Tribal, Local, and Territorial (STLT) health departments launch effective contact tracing programs. CDC field assignees are embedded in health departments across the nation to directly assist STLT health departments in responding to COVID-19. Moreover, CDC links STLTs with other federal agencies, academia, and other organizations that offer contact tracing and case management staffing solutions.

To support surge staffing needs in health departments and tribal communities, CDC funded the CDC Foundationexternal icon to hire local staff to enhance STLT jurisdictions’ COVID-19 response efforts, including contact tracing. The CDC Foundation will work with health departments and Area Indian Health Boards (AIHBs) to hire and place public health professionals, including contact tracers, in health departments and AIHBs. Also, CDC’s COVID-19 Response and Division of STD Prevention are supporting two cooperative agreements to train the COVID-19 contact tracing workforce. The newly funded National Network Disease Intervention Training Centers (NNDITC) and the Association of State and Territorial Health Officials (ASTHO), in partnership with the National Coalition of STD Directors (NCSD), are leading a nationwide, coordinated training effort to build a well-trained public health COVID-19 contact tracing workforce, including case investigators, contact tracers, and contact tracing supervisors. Learn more about the CDC-funding training for the COVID-19 contact tracing workforce pdf icon[PDF – 2 pages].

For more information, visit CDC’s staffing webpage.

Digital tools and information

illustration of a woman's hands answering a phone call, next to an illustration of a woman in a call center
What types of digital tools are used for contact tracing?

There are two types of digital tools that health departments can use pdf icon[PDF – 2 pages] to help with contact tracing: case management tools and proximity tracing/exposure notification tools.

  • Case management tools can help make the contact tracing process faster and more efficient. These tools help health departments manage information they receive from people who have been diagnosed with COVID-19 (cases) and people who they were around (contacts). Many case management tools have features that automatically send important information to recipients. These features can include text messaging and emails to help individuals monitor their symptoms each day. They can also help health departments prioritize their work to have the greatest impact on slowing the spread of COVID-19. Case management tools can be used to augment and streamline traditional contact tracing methods, including phone calls.
  • Proximity tracing/exposure notification tools can help health departments let a person know that they may have been exposed to COVID-19 faster than traditional contact tracing practices. Proximity tracing/exposure notification tools are voluntary smartphone apps that a person can choose to participate in by downloading the app to their cell phone. If a person chooses to download the app, it uses existing information from their cell phone about the user’s location (e.g., Bluetooth or Global Positioning System (GPS)). The tool alerts the user if they have been in the same area as a person who has been diagnosed with COVID-19 and may have been exposed to COVID-19. Then the app may ask users if they would like to participate in their local health department’s follow-up and symptom monitoring process. These types of tools may be developed in collaboration with, or are endorsed by, state and local health departments. These apps may undergo rigorous testing to determine their trustworthiness, security, and ability to protect individuals’ privacy. For more information, please contact your state or local health department.
Will there be a “national app” for contact tracing?

No, there will not be a national app for contact tracing. There are many options available now, and it is up to each state and individual to decide which tools best fit their needs.

Is personal health information collected through the health department’s case management tool secure?

Yes, while the security and privacy protection methods are dependent on the health department’s regulations and implementation, CDC recommends that information collected through the health department’s case management tools for COVID-19 be secure and stored with the health department. These tools help health departments quickly collect and analyze information about COVID-19. Case management tools are under the same laws and regulations for all sensitive health information use (e.g. HIPAA). An individual must provide consent for their health department to collect information using a case management tool. Public health departments should follow the rules and practices for managing personal health information and restricting access to sensitive information. For more information on privacy and security guidelines, visit CDC’s Guidelines for the Implementation and Use of Digital Tools to Augment Traditional Contact Tracing pdf icon[PDF – 7 pages].

Are people required to download an application, “app,” to give information for contact tracing for COVID-19?

No, individuals are not required to download an app to give information for contact tracing for COVID-19. Health departments commonly use case management tools to make the contact tracing process more efficient. These types of tools are not downloaded on personal cell phones. Case management tools can be used to augment and streamline traditional contact tracing methods, including phone calls.

It is up to the individual to decide if he or she downloads a proximity tracing/exposure notification app for COVID-19.

Which states use digital tools for contact tracing?

Case management tools: Almost all states have implemented using a case management tool to help make the contact tracing process more efficient, including for monitoring the health of patients and contacts. These tools may include automated text, email, or phone notifications, reminders, or surveys.

Proximity tracing/exposure notification tools: As of July 2020, exposure notification tools are not widely used to help with contact tracing in the United States. Several states are beginning to use these apps in pilot projects to see how effective they are in helping with contact tracing. At the beginning of August, Virginia became the first state to launch an Exposure Notification Application using the Apple|Google Exposure Notification Frameworkexternal icon. Visit VA’s COVIDWISEexternal icon website for more information. COVID Alert NJexternal icon is New Jersey’s free and secure mobile app that anonymously alerts users if they have been in close contact with someone who has tested positive for COVID-19.​

Visit CDC’s website to learn more about using digital tools for contact tracing pdf icon[PDF – 2 pages].

What is CDC doing with digital tools to support contact tracing?

CDC continues to provide guidance and technical assistance to state, territorial, local, and tribal health departments in choosing which digital tool will be most effective to use for COVID-19 contact tracing.

CDC works with partners to study how effective and useful the types of digital tools are in different settings to develop additional guidance for COVID-19 contact tracing.

Visit CDC’s website for more information on CDC’s Contact Tracing Resources.