Key TakeawaysExposure Notification is a smartphone-powered tool used to augmenttraditional contact tracingUsers’ phones send and receive non-identifiable Bluetooth keys when people they have come into proximity with for more than 15 minutes test positive for COVID-19Nineteen states have approved the use of this technology, with more likely to come in the future.

Key Takeaways

Exposure Notification is a smartphone-powered tool used to augmenttraditional contact tracingUsers’ phones send and receive non-identifiable Bluetooth keys when people they have come into proximity with for more than 15 minutes test positive for COVID-19Nineteen states have approved the use of this technology, with more likely to come in the future.

Julie Samuels, the Executive Director of Tech:NYC, a non-profit organization that developed COVID Alert NY, tells Verywell that this technology is meant to complement traditionalcontact tracing, which relies on officials to track and trace people who have had exposure to someone with COVID-19.

“This app is a tool that will help contact tracers increase the availability of contact tracing in the population; it will not replace traditional contact tracing," she says.

Kameka Dempsey, a member of the COVID-19 Technology Task Force, tells Verywell that exposure notifications fill the gaps where conventional methods fall short.

“People don’t remember where they were the day before, let alone for two whole weeks,” she says. “What manual contact tracing doesn’t offer either is the connection with strangers or people we don’t know.”

Contact Tracing Apps Aim to Slow Spread of COVID-19

Who Developed This Technology?

As Dempsey notes, state public health authorities then have options on how to deploy this framework.

“There are two paths that you could choose—you can decide to do a custom-built app, or you can use the express version,” she says. “The custom app version is when you get a third-party developer to build an app over the Google and Apple built API.”

The second path, known as EN express, doesn’t require public health departments to develop their own applications.

“On iOS, that’s app-less because it is just turning on a setting inside the operating system on iPhone," she says. “On Android, it’s app-light because it is a Google minted app—the public health authority would give Google the parameters, and then Google does the build for that app using the given settings.”

How to Activate Exposure Notifications

On iOS 13.5 or later:

Go to Settings –> Exposure Notifications –> Turn on Exposure Notifications –> Choose your country and state –> Download the application

On Android 6.0 or later:

How Does It Work?

“Let’s say Alice and Bob are sitting on a bench, they don’t know each other, and they have a lengthy conversation sitting just a few feet apart,” Dempsey says. “Their phones are exchanging non-identifiable Bluetooth tokens which change frequently while they’re having this conversation. Each phone keeps a local record of the last 14 days of keys received, essentially as a virtual log of all the possible exposures a person has had.”

If a few days later Bob receives a positive diagnosis for COVID-19, he would receive a code from his public health authorities which he could input into the app.

Exposure Notification technology relies on people proactively and willingly updating their COVID-19 status in an app.

“Then what happens is, with Bob’s consent, he uploads the last 14 days of his Bluetooth keys to the national key server,” she continues.

During this time, Alice’s phone will be periodically downloading all the encrypted keys from people who tested positive in her region and chose to share their results.

“So then when the match is made between Bob and Alice’s key, that’s when she gets an alert, but it doesn’t tell her that it was from Bob; she has no idea who it was,” Dempsey explains.

Mitigating Privacy Concerns

The use of Bluetooth, combined with the constantly changing keys, ensures that no identifiable information is ever transmitted between users.

Privacy Concerns Continue To Prevent Contact Tracing App Use

Another key emphasis on privacy is that all decisions require the consent of the user.

“I think it’s important to note about privacy that the user has choice along the way,” Dempsey says. “There are three different points along the way that I like to highlight where an individual has to make the decision to participate in this public health tool.”

Why Hasn’t This Been Implemented Nationwide?

“In countries outside the US, it’s one country, one app," she says. “In the U.S., because we don’t have a national public health authority, it has to be federated to the states.”

Despite the states setting their own parameters and, in some cases, making their own standalone apps, all keys are still uploaded to the same national key server, allowing for compatibility across state lines.

Samuels says that despite this decentralized structure, there is still a path for a federal implementation of this technology.

What This Means For YouExposure Notification cannot collect or share any information about your location or identity outside of your department of health. Check your state’s public health authority to see if they are participating in this technology. Exposure Notification can be an effective tool to increase awareness of potential COVID-19 exposure.

What This Means For You

Exposure Notification cannot collect or share any information about your location or identity outside of your department of health. Check your state’s public health authority to see if they are participating in this technology. Exposure Notification can be an effective tool to increase awareness of potential COVID-19 exposure.

“I am optimistic that the Biden administration will nationalize this, and we will see a national contact tracing app from the CDC,” she says.

Samuels tells Verywell that the lack of awareness about exposure notification is a major reason for its slow implementation in the U.S.

“I think the best option would be to call your governor’s office, write letters to the editor of your local newspapers and make some noise that you want this,” she says. “The state is going to need some resources to build this, so it is important to put pressure on your state government.”

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 ourcoronavirus news page.

3 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Google COVID-19 information & resources.Exposure notifications: using technology to help public health authorities fight COVID‑19.Association of Public Health Laboratories.Exposure notifications.Abueg M, Hinch R, Wu N, et al.Modeling the combined effect of digital exposure notification and non-pharmaceutical interventions on the COVID-19 epidemic in Washington state.Epidemiology.2020. doi:10.1101/2020.08.29.20184135

3 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Google COVID-19 information & resources.Exposure notifications: using technology to help public health authorities fight COVID‑19.Association of Public Health Laboratories.Exposure notifications.Abueg M, Hinch R, Wu N, et al.Modeling the combined effect of digital exposure notification and non-pharmaceutical interventions on the COVID-19 epidemic in Washington state.Epidemiology.2020. doi:10.1101/2020.08.29.20184135

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Google COVID-19 information & resources.Exposure notifications: using technology to help public health authorities fight COVID‑19.Association of Public Health Laboratories.Exposure notifications.Abueg M, Hinch R, Wu N, et al.Modeling the combined effect of digital exposure notification and non-pharmaceutical interventions on the COVID-19 epidemic in Washington state.Epidemiology.2020. doi:10.1101/2020.08.29.20184135

Google COVID-19 information & resources.Exposure notifications: using technology to help public health authorities fight COVID‑19.

Association of Public Health Laboratories.Exposure notifications.

Abueg M, Hinch R, Wu N, et al.Modeling the combined effect of digital exposure notification and non-pharmaceutical interventions on the COVID-19 epidemic in Washington state.Epidemiology.2020. doi:10.1101/2020.08.29.20184135

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