How the Pennsylvania COVID-19 Alert App Works

We hope these apps will help you track your contacts. So far, we have relied on finding people to come in contact with other people who test positive for the virus.

September 24, 2020 | 7:41 am

(Philadelphia) — Pennsylvania Released COVID-19 Alert App This tells the user if they are in close contact with someone who has tested positive for the new coronavirus. Delaware released That app Last week and new jersey There is one in the work.

We hope these apps will help you track your contacts. So far, we have relied on finding people to come in contact with other people who test positive for the virus.

Contact tracking works if you know people who were nearby. But if you’re near a stranger, or if you forget someone who was nearby, or if the contact tracer doesn’t respond to attempts to reach you, it won’t work.

Pennsylvania Governor Tom Wolfe said about 75% of people would respond when contacted by a contact tracer. The idea is that with this app, more people will notice if they were close to someone who tested positive.

Pennsylvania and Delaware Part of a collaboration with the Association of Public Health LaboratoriesSo people traveling to different states don’t need to download another app to get exposure notification alerts. App contracts in Pennsylvania $ 1.9 million federal grant.. New jersey Announced last week Use a similar app, but first pilot it on several university campuses.

However, health authorities in Pennsylvania and Delaware are promoting privacy protection because the app is only valid if people are willing to download it and upload positive COVID-19 test results.

How does the app work?

Pennsylvania and Delaware apps Apple and Google Bluetooth platforms It sends a string of random numbers called a chirp. A chirp is something that other smartphones with the app can listen to and record. Their number changes Every 10 to 20 minutes..

If someone turns positive, that person’s phone app can upload all the random numbers that the phone has sent to other phones in the last 14 days. Another person who has the app can download the list of numbers, and that person’s phone can match the list with the numbers it contacts. The match is done on the user’s phone, not on the government database, so only the user knows if the phone was matched with another phone.

You can choose to be tested if there is a match that indicates that you are in close contact with someone who has tested positive. If you get good results, you can put it in your app to alert other app users nearby. Close contact means staying within 6 feet of another phone for at least 15 minutes.

By design, all these steps said that someone had to be proactive in doing something with the app. Mark Jissman, The person who worked on the app. He is Deputy Head of Cyber ​​Security and Information Science at MIT’s Lincoln Laboratory.

“Let’s see how private it is.” “I was a sick person, what happened? I uploaded all the chirps I sent in the last two weeks, but those chirps are me. There was nothing in it.

“As a contact person, what you did was download all those chirps, compare them and find that you are approaching someone who is sick. It is that you are close. I didn’t tell you that I was, it just told you, “Hey, you were near a sick person.”

“It’s up to you if you want to call your public health authorities and let them know if you’ve received these warnings,” he said. “I think I can quarantine myself for two weeks … I’d better inform the public health authorities, but I don’t have to.”

Zissman said the team behind the app wanted a system that would work in other countries as well, so they chose to focus on privacy.

“Not all countries are liberal democracy. We wanted to ensure the privacy of people around the world, not just where it has a good bill of rights.”

He wrote the source code for the Irish developer NearForm’s app Available online, So people can see exactly what it does.

Why are people worried about privacy?

Some have expressed concern About Privacy Problems with the COVID-19 Exposure Notification app.

When Delaware released the app last week, it encouraged employees in all states to download it. A public school teacher told WHYY News that she initially saw this as a “privacy breach” and was skeptical that the app wouldn’t collect information such as location data. After learning how the app works, she rethinks.

Part of her hesitation is from Norwegian health authorities I had to pause the app and delete all the data Because the data protection authorities there said it broke into people’s privacy. The Norwegian app did not use Apple’s and Google’s Bluetooth frameworks and sent both Bluetooth and location data to a central server.

Last month, TechCrunch Reported A small liberal arts college in Michigan has launched a contact tracking app from a private company that has been vulnerable to security vulnerabilities that could lead an attacker to infer the student’s COVID-19 status by tracking the student’s location I asked the students to download it. Parents have begun to petition for the app to be an option. Bucknell University in central Pennsylvania also uses the app, but the school tells its students You can choose to turn it off Location tracking.

The amount of data the COVID exposure notification app collects is a trade-off between user privacy and easy contact tracking.

In some countries we chose tracing. For example, Australia does not use Apple and Google models. Allow access to contact tracers For information about people who may have been exposed to the coronavirus. Singapore made the same decision. Foreign Minister Explained in June The Apple and Google approaches are ineffective and do not provide authorities with information about when and how people were infected.

Does the app really help you track your contacts?

It’s too early to say for sure. Switzerland was the first country to adopt an exposure notification app using Apple and Google platforms, and researchers have not yet reviewed the study. Some early evidence that it doeshelp.

Privacy protection actually makes it difficult to study this. Swiss Researcher notesLimiting information to a user’s device means that “data needed to assess its effectiveness” must be collected elsewhere.

The app also depends on how easy it is for people to take the test.

“This is a way to supplement traditional contact tracking. It’s not a silver bullet and it doesn’t work on its own,” Zissman said. “But this is a way that technology could be used to make this pandemic a little better than before.”

Will people use it?

Switzerland and Ireland have adopted Apple and Google’s exposure notification technology early on, with at least some people downloading the app.

As of August About 33% of Ireland’s population I was downloading an app for that country. Ah National Survey of Ireland Not yet peer-reviewed It showed that more than 80% of the people surveyed would be willing to download the exposure notification app, mainly because it would be useful to family and friends. That is.

Swiss app Downloaded 1.6 million times in July, but the number of active users has declined since then..

As of September 23, more than 56,000 people have downloaded the Pennsylvania COVID Alert App and more than 25,000 have downloaded the app in Delaware.

WHYY is a leading public media station serving the Philadelphia region, including Delaware, South Jersey, and Pennsylvania. This story originally appearedWHYY.org..