Adding Wearables to Extend the Reach of
COVID-19 Exposure Notification Systems

The Bluetooth Special Interest Group (SIG) is creating a specification that will standardize support for wearable devices within existing smartphone-based COVID-19 Exposure Notification Systems (ENS). This effort is taking place within the Exposure Notification Working Group, which is open to all Bluetooth SIG member companies.


Wearable Exposure Notification Service
(Draft – 03 Dec 2020)

Review the working draft of the Bluetooth specification that will define a standardized approach for supporting wearable devices within an existing smartphone-based COVID-19 Exposure Notification System (ENS).


Feedback is welcome


If you are a Bluetooth SIG member:

Bluetooth SIG member companies may provide feedback by joining the Exposure Notification Working Group, which is open to all member companies. 

If you are with a government agency:

Government agencies, such as public health authorities, can register to provide feedback.

If you are with a commercial entity that is not a Bluetooth SIG member:

All commercial entities are welcome to join the Bluetooth SIG to provide feedback as well as participate in the Exposure Notification Working Group.

What is an ENS?

Typically deployed by a government health agency, an Exposure Notification System (ENS) leverages Bluetooth® technology embedded in smartphones to inform people when they have been in proximity to someone who was later diagnosed with COVID-19. The Exposure Notification System created jointly by Google and Apple, is a well-known example of an ENS.


How many people need to participate in an ENS for it to be effective?

An ENS can be effective at any level of uptake, according to research published by a team at Oxford University, with a general rule that one infection can be averted for every one to two users of the system.

While an ENS has a positive effect even at low levels of adoption, the more people who participate the more effective an ENS becomes. In fact, the same research estimated that even if an ENS was the only method being used to contain the virus, an adoption level of approximately 60% could completely stop the spread of COVID-19. When deployment of an ENS is combined with other measures such as wearing masks and practicing social distancing, as is typically the case, the adoption level required to stop the spread is much lower.

Learn more


Why are wearables needed in an ENS?

Due to their broad adoption, smartphones represent an ideal foundation for launching an ENS. However, smartphones on their own are not a practical approach to cover all segments of the population.

“There are several population groups critical to managing the spread of diseases like COVID-19 with relatively low smartphone penetration, presenting a coverage challenge for smartphone-based Exposure Notification Systems. We believe including wearable devices in an ENS would be a very effective method for extending its reach to support these important groups.”
Elisa Resconi, Physics professor at the Technical University of Munich leading research on non-pharmaceutical interventions against COVID-19

Extending an ENS to Support Wearable Devices

Sarah would like to know if her son Steve is exposed to someone infected with COVID-19 but Steve is too young to have a smartphone.

She acquires an ENS-enabled wristband for her son and pairs it with her smartphone using the ENS app. Steve’s wristband begins broadcasting its own unique random IDs.

Steve wears his wristband throughout the day, and it exchanges random IDs with other nearby ENS-enabled devices, storing all received IDs.

Steve’s wristband periodically connects to Sarah’s smartphone and uploads its list of recently received IDs.

Sarah’s smartphone periodically retrieves the list of IDs associated with positive COVID-19 cases and compares it to the list of received IDs from Steve’s wristband. If the ENS app discovers any matches, it notifies Sarah with further instructions for Steve.

Related Resources

Exposure Notification Working Group

The Exposure Notification Working Group (ENWG) will serve as a centralized forum in the…

Bluetooth SIG to Extend Reach of COVID-19 Exposure Notification Systems

Effort underway to standardize support for wearable devices in smartphone-based Exposure Notification Systems…

Extending an ENS to Support Wearable Devices

See how an ENS can better address population groups critical to managing a pandemic by supporting wearables…