Digital Contact Tracing Tools
CDC is reviewing this page to align with updated guidance.
There will be emerging information on smartphone-based exposure notifications from proximity tracking tools that could significantly increase the number of contacts that health departments are alerted to. As these tools are implemented, they should be used to initiate contact notification.
Case management tools for case investigation and contact tracing capture data on cases and contacts and can help improve the efficiency of manual contact tracing and medical monitoring methodologies. A case management tool should generally have the following capabilities:
- Ability to ensure data security and confidentiality of significant volumes of client information, which is critical to maintain community trust in using any case management tool.
- Interoperability capabilities to receive input from the public health authorities (PHA) (including local, state, tribal, and territorial public health departments), information systems and/or laboratory systems, either via import or real-time synchronization.
- Ability to facilitate identification/elicitation and documentation of known contacts of clients with COVID-19, both through manual entry by the PHA and via self-report from cases.
- Ability to send notifications to users (clients and contacts) via manual and/or automated means. These messages will include:
- Notification to contacts of their exposure and time window when exposure may have occurred.
- Initial survey about their symptoms and clear instructions on how to regularly monitor their symptoms and health status and report that information every day. (This will ensure their data reaches the contact management team at the PHA and that aggregate data reach relevant state and federal partners.)
- Public safety messages to identified contacts to educate them about COVID-19, its common signs and symptoms, and reinforcing prevention messages defined by the government, such as self-quarantine and social distancing. (This messaging should be repeated daily throughout the contact’s self-quarantine period with new information supportive of the evolving stage of isolation.)
- Ability to send notifications in multiple formats, such as voice messages, emails, and SMS.
- Capability for contact-generated and system-generated alerts or workflows (e.g., to facilitate appropriate follow-up, presence of symptoms, contact request for information).
- Ability to produce individual-level and aggregate data supporting worker and PHA-level process metrics as described above.
Preliminary evaluations were conducted on ready-to-implement tools (e.g., proximity contact tracing, medical monitoring aids, data management systems) based on CDC Guidelines for the Implementation and Use of Digital Tools to Augment Traditional Contact Tracing [125 KB, 5 Pages]. CDC continues to evaluate tools and assess their suitability for use to facilitate specific activities in the case investigation, contact tracing, and monitoring workflows.
A variety of medical monitoring tools are currently in use by health departments to communicate with clients and contacts for TB, and other infectious diseases. These tools can help improve the efficiency in medical monitoring in both active engagement (e.g., Skype, Facetime, Zoom) of high-risk individuals, and self-report of daily temperature check, signs and symptoms (e.g., recorded video) for others diagnosed or exposed to COVID-19. In addition, some case management systems have built in technology to push system-generated alerts (e.g., request to check-in the day prior to end of patient self-isolation or contact self-quarantine).
As case management tools are developed, it is critical to ensure the information is appropriately used and that the data security and confidentiality of patient information are maintained.
There are numerous initiatives that propose to use smartphones as “sensors” to detect proximity and exposure to individuals who may have COVID-19. Proximity-tracking tools propose to relieve several challenges associated with traditional case investigation and contact tracing and have been implemented in several countries. Several ongoing efforts in the United States and internationally seek to develop privacy-preserving, accurate, and energy-efficient applications for use on mobile devices. There are currently very limited data on the performance of these applications in US communities; particularly the sensitivity and specificity of these methods as it pertains to identifying true close contacts. Many tools are not yet widely available, and there remain critical gaps that could pose challenges to their implementation.
There are two major technologies that are under discussion in the United States – Bluetooth and GPS. There are currently little published empirical data showing the capabilities of either technology. Some preliminary advantages, disadvantages, and implementation challenges are listed below. It is assumed that appropriate consent is obtained from the individuals involved.
- Potentially creates a higher likelihood of buy-in from patients and users by prioritizing individual trust.
- Augments capacity of case investigator and contact tracer workforce (e.g., may decrease burden of manual contact elicitation, help to identify contacts in a timelier manner, facilitate communication with contacts, and help ensure rapid isolation of contacts to interrupt the chain of transmission).
- Augments contact identification by identifying potentially unknown contacts.
- Provides more comprehensive mobility history, which allows the contact to better detail their movements and provides public health authorities with more accurate information in the aggregate.
- Provides granularity of proximity and associated temporal data that may be useful in stratifying contacts into different exposure risk categories that PHAs can match with differing levels of tracing, notification and monitoring.
- Has inherent socioeconomic and technology literacy biases – requires that client and contacts have access to a smartphone, knowledge of how to install apps, and literacy to navigate app menus.
- May not be effective until a “critical mass” of users in a community are using the apps.
- Requires individuals to keep their smartphones on them at all times with the appropriate functions enabled and depends on users to elect to share their information with PHAs.
- Disparate data formats from multiple apps may not be interoperable and could add burden on PHAs for integrating data seamlessly into their case management and contact tracing systems and workflows.
- Expansion of tool capabilities will require more consultation on the ethical and legal issues related to electronic tracking.
- Hacking and other unauthorized access or use of data may compromise data security and confidentiality.
- Social mobilization and mass marketing media campaigns are required to gain a critical mass behind one or more application for broad public usage.
- Building and sustaining public trust in PHA’s ability and intention to preserve the privacy of individuals is crucial to widespread adoption of new technologies.
- Systems are needed to integrate disparate data streams into PHA information systems without compromising the integrity of existing workflows and to safeguard against false-positive alerts.
For more information on digital contact tracing, visit the following resources: