“U no more chance of successfully breaking out of confinement ”, this is how Cédric O presents TousAntiCovid. The Secretary of State for Digital hopes to reach 15 million downloads of this contact tracing app by early December. ” Inserm has modeled an extremely significant impact of the application if it is downloaded by a minimum of 20% of French people ”, he asserts.
Launched on October 22, TousAntiCovid is supposed to detect, when activated, other users located within a meter for more than 15 minutes. If one of the people crossed has tested positive for Covid-19 on the application, a notification is sent to all smartphones that have been found nearby.
With 9.2 million downloads recorded on November 20, it is more successful than its old version StopCovid. The latter had recorded just over 2 million downloads four months after its launch on June 2, suffering in particular from a disastrous communication. On September 24, even Prime Minister Jean Castex admitted not having installed it… TousAntiCovid was entitled to his presentation to the French by President Emmanuel Macron during his televised address on October 28. It has also been given additional features (data on the evolution of the epidemic, access to derogatory certificates) to encourage its download.
The government hopes to be able to rely on the application during deconfinement to make contact tracing more effective. “Digital tracing can facilitate human tracing. In IT terms, we say that it “goes better at scale”. If we have 1000 case per day, tracing can be done manually but if we have 50,000 it is much more complex. O n control the epidemic less well because we are less able to alert people and tell them that they must isolate themselves ”, explains Sonia Ben Mokhtar, research director at CNRS.
This tracing can prove particularly useful according to the researcher in spaces that escape manual tracing, for example ” in the transports or supermarkets “. The application could also make it possible to remedy any oversights. “It is sometimes difficult to remember precisely over several days who we really met for a long time”, emphasizes Sonia Ben Mokthar.
Logically, the more the application is downloaded, the more efficient it will be. It is also necessary to know how many people are notified in the event of contact with a positive person. “Since October 22, for 100 cases declared in the application we have on average 33 users notified as contacts at risk”, indicates the Ministry of Health. The application reports 12,850 people notified following exposure to Covid-19 since June 2 (since the launch of StopCovid). A number “Relatively insignificant” according to Baptiste Robert. “The application sends around 600 notifications per day while we have between 20,000 and 30,000 new cases daily”, notes the researcher, “ this is cosmetics’.
In addition, if the application indicates how many people have downloaded it since June 2, it does not display the number of users who have since uninstalled it, nor the proportion of people who are actually active. “ Downloading is not everything, if the application is not activated, it is of no use “, recalls Sonia Ben Mokhtar. “It is impossible to track the number of activations and deactivations of the application”, says the Ministry of Health. A “Assumed opacity”, according to Baptiste Robert who judges “Difficult to reach” the goal of Cédric O. “Not all populations have the same relationship to technology. If you are 20 years old, have a powerful smartphone and you live in an urban area a priori there is no problem, but if you are 80 and do not understand anything, it is more complicated ”, he believes.
To top it off, several users reported difficulties obtaining the QR code needed to register as positive for Covid-19 on the app. A problem, when we know that its usefulness is based on the declaration of positive cases to be able to alert other users. On November 20, TousAntiCovid reported 48,600 positive cases. A relatively low figure, for a total of just over 2 million positive cases indicated by Public Health France.
Finally, the technology used for tracing, which is based on Bluetooth, is not known for its accuracy either. “It is not made to measure distances, explains Baptiste Robert, on this type of application, we estimate the margin of error between 20 and 30% “. But Bluetooth also allows better protection of privacy compared to other techniques.“ To measure the distance between two phones, d Applications could use GPS, for example. However, location data is extremely sensitive and can divulge a lot of information about individuals, where they live, the places they visit. L e Bluetooth pe rmits to know that a telephone has crossed another telephone but without knowing where “, shade Sonia Ben Mokhtar. The intrusion into privacy and the fear of being tracked are indeed part of the factors of reluctance to install the application. AllAntiCovid has a little less than two weeks left to try to reassure and achieve its goal.