The effectiveness of Australia’s COVIDSafe app, which tracks contacts between users via bluetooth technology, has been called into question, with some people going so far as to claim that it hasn’t detected any cases of infection. Thankfully Australia's number of infected people, while tragic, is much lower in the rest of the world, meaning that there’s comparatively few cases for it to detect.

In other countries, have such apps had a track record of detecting a non-trivial number of infections?

I came across a Full Fact article from last month that doesn’t list any major success stories.

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    Can you please edit the question explain what this COVIDSafe app does? It's not clear to me how an app would "detect" cases. It's nothing like this is it? qz.com/1825997/…
    – Brian Z
    Jul 9, 2020 at 13:19
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    please provide a source for " Australia’s COVIDSafe app has been called into question".
    – BobE
    Jul 9, 2020 at 13:40
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    The various contact tracing apps are supposed to alert you if you have been in contact with someone who had covid. If you then get tested and are found to have covid then in a sense the app could be credited with detecting that case.
    – Eric Nolan
    Jul 9, 2020 at 15:03

3 Answers 3


Probably too early to tell. Germany has rolled out an app and people have been advised that they were in proximity to a person who later tested positive. As of July 3rd, the contacts of some 300 patients were informed (Source in German).


South Korea (probably)

Contact tracing is seen as one of the main tools the South Korean government used to control the outbreak in the country.

Contact tracing started early in the country. According to Wikipedia,

In its efforts to fight and contain the virus, South Korea has combined testing with contact tracing.[citation needed]

Infected South Koreans are required to go into isolation in government shelters. Their phones and credit card data are used to trace their prior movements and find their contacts. Those who are determined to have been near the infected individual receive phone alerts with information about their prior movements.

"People that had been near infected people received alerts on their phone" has to be taken in a broad meaning. For example, I leave in Busan, the second city of South Korea (3.5 millions spread on a very large area) and I received daily in February and March alerts about infected that went to areas far from my neighborhood. You can also check on the city's official website (in Korean) the whereabouts of the local infected people: Busan website. You can find an English version of the log of an infected Korean in this BBC article. This website can show you the position of infected people in the past weeks and this website uses geolocalisation to tell you if you had been in close proximity of an infected person. Both are individual initiatives though, but they were widely used in the country.

In addition, a contact tracing app later reinforced this contact tracing strategy. From Business Insider

A government app tracks the location of all new visitors to the country; people who violate quarantine have to wear a location-tracking bracelet;

Visitors here means foreigners and Korean returning to their country from abroad. This proves to be efficient to limit clusters started by imported cases. An example: a South Korean that recently came back to the country visited several night-clubs in the entertainment district of the capital city and obviously came into close proximity with many people. From Business Insider,

After the country relaxed its social distancing as the number of new daily cases dropped into the single digits, several people who visited nightclubs in Seoul tested positive for the virus. [...]

The country's response is a how-to in contact tracing. Seoul's mayor shut down all bars and nightclubs in the city. Within two weeks, South Korean officials had tracked down 46,000 people who had contact with known infected partygoers and tested them for COVID-19.

Of course, we cannot be sure how much impact the app had. This app is just one tool of a strategy of contact tracing, combined with other elements (early numerous and cheap test, transparency and information of the population,...) in a global strategy.

  • Didn't Taiwan develop one too?
    – m13op22
    Jul 15, 2020 at 20:18
  • No idea. Taiwan handled the situation extremely well, so it is a good idea to check how they did
    – Taladris
    Jul 16, 2020 at 1:27
  • This is one article I could find about Taiwan's tracing app. There are more out there, like this opinion article, but I think the first is more objective.
    – m13op22
    Jul 19, 2020 at 16:44
  • @HS-nebula: feel free to write your own answer :)
    – Taladris
    Jul 19, 2020 at 23:28

The Swiss tracing app has in at least one case alerted a person of having infected contacts who turned out to be infected.

  • While I don't particularly doubt the claim, a random Twitter user making a claim about an unidentified acquaintance is not exactly a reliable source. And the tweet doesn't even claim that the unidentified acquaintance got tested because of the app. The claim is only that the acquaintance got notified by the app and got tested, with no explicit claim of causation.
    – Peter
    Jul 13, 2020 at 18:57

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