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News 5 Investigates: Is the state's COVID-19 exposure notification app working?

COVID Exposure Notification
Posted at 3:34 PM, Jan 28, 2021
and last updated 2021-02-09 18:31:02-05

SOUTHERN COLORADO — It has been 3 months since the state launched its COVID-19 exposure notification system for iPhone and Android users.

The system is supposed to work by sending push alerts when you've come into contact with someone who has tested positive, but News 5 has heard from viewers who are confused with how the app operates.

For tech savvy consumers, you've probably noticed there's a bunch of data your phone is collecting in the form of "matched key counts".

If that number is "0"---there's nothing to worry about. However, some users have reported seeing "matched key count" numbers like "1", "5", or even "7". What does this mean?

Matched Key Count Log
Matched Key Count Log

The state's COVID-19 Joint Information Center allowed News 5 to interview Sarah Tuneberg, a senior adviser familiar with the applications functionality.

"A matched key indicates that your phone has detected an encounter with a person who has a positive test result," Tuneberg said. "However, that encounter was not long enough or close enough to be considered an exposure."

Sarah Tuneberg
Sarah Tuneberg talking via Zoom with KOAA

Following CDC guidance, the state says you will not receive an exposure notification unless your phone is within 6 feet to another phone user who tested positive.

Also, you have to be within 6 feet of that user for at least 15 minutes in order for an alert to be triggered.

Exposure Notification System
COVID-19 Exposure Notification System

In some cases, users have also noticed that their smartphone is logging "matched key count" numbers at random times of the day---sometimes showing a match in the middle of the night when most people are asleep.

Matched Key Log
COVID-19 Matched Key Log Data

Here's why: the application does not update in real-time.

"It's not when you cross paths with that other phone," Tuneberg explained. "It's when the cloud keys linked together and noticed the matched key."


How it works: Notification System
Example of how the COVID-19 notification system works

Let's say you go grocery shopping at 3 p.m.

An hour or two later when the cloud updates, it will log a "matched key count"---indicating the number of users you've come into contact with that have COVID-19.

Bottom line: You should not count on the notification system to update you in real-time when you approach someone who has tested positive for COVID-19. That's not how this system is designed or set up.

If you already opted in for the COVID-19 notification system when it first launched, you should only be concerned if you've personally received a push notification to your smartphone.

Keep in mind, this app is not 100-percent accurate since there could be people you're in close contact with who have chosen not to participate in the system---but tested positive.

For more information on the COVID-19 exposure notification app, click here.

As of early January, more than 1.4 million users have opted in for COVID-19 app notifications.

Disclaimer: You should never wait for an app to notify you to get tested. You are the best line of defense when it comes to your personal safety. If you think you've been exposed, it's important to get tested on your own and if you feel sick, doctors encourage you to stay home.

Do you have a question or problem you'd like our News 5 Investigates team to look into? Email us: