TousAntiCovid: growing success, but for what effectiveness?

In an interview on October 14, after acknowledging the flop of the first version of the StopCovid tracking application, Emmanuel Macron announced the launch of a second version: TousAntiCovid.

If the download figures for the new application show a much greater appropriation than its predecessor, its use – and above all its first object: to notify the population – is still far from the objective of collective information. This is confirmed by the crossed views of Baptiste Robert, expert in cybersecurity, and Pascal Crépey, teacher-researcher in epidemiology and biostatistics.

A “Macron effect” in the increase in downloads

Available in stores since October 22, the new baby from health authorities has been activated on nearly seven million devices. Indeed, the 10 million mentioned by the President of the Republic, during his recent intervention, together count the downloads of the first and second application.

TousAntiCovid: growing success, but for what effectiveness?

Since then, the increase in downloads has been undeniable. Where StopCovid struggled to reach three million users in more than four months, TousAntiCovid did three times better in just one month. Nearly one in seven French people is now equipped.

Looking at the figures closely, the President of the Republic himself seems to be a good ambassador for the system. The day after his speech on October 28, a peak of 368,000 activations was observed, while the trend was downward the previous days.

TousAntiCovid: growing success, but for what effectiveness?

However, his role as VRP seems to be running out of steam. Closely scrutinized during his last intervention on November 24, activations shuddered, at 40,000 in one day. This is almost ten times less than during his previous speech. “We could have hoped for a more significant president effect” given the hearings of his speech and the explosion of the figures observed initially “, remarks Baptiste Robert.

A follow-up of contact cases still insufficient

TousAntiCovid “is essential for identifying contact cases,” says Emmanuel Macron. For Baptiste Robert, renowned hacker, the results are less glowing. “Today, TousAntiCovid’s contribution to the contact tracing is ridiculous, it is almost useless, ”said the cybersecurity expert, called upon to identify possible flaws in the system.

A more nuanced observation from Pascal Crépy: “14,000 notified people is not nothing, but above all we must take into account all the people who have not been infected by the notified people. Some went to be tested and many of them certainly changed their behavior after being warned ”.

TousAntiCovid: growing success, but for what effectiveness?

As the incidence decreases, the number of notifications also seems to be decreasing. Last week, less than 200 notifications were sent on average each day. Which leads Baptiste Robert to suppose that the French use “more the application for its generator of exit certificates than for the follow-up of contact cases”.

“The integration of certificates and numbers into the new version of the app was neat. It gives an additional reason to connect ”, notes Pascal Crépey.

The number of regular users remains unknown

In the absence of usage data, it remains difficult to know the actual use of the application. Indeed, the Ministry of Health only communicates the total number of people who have activated TousAntiCovid at least once, and not those who activate it regularly.

“The estimate is technically possible. Switzerland, for example, communicates this number ”, affirms François Lesueur, researcher and lecturer in computer science at INSA Lyon. “The users who activate the application every day, this is called retention, and it is an extremely important point to evaluate the effectiveness of the device”, adds Baptiste Robert.

Among our European neighbors, the appropriation of similar systems is more important. In Ireland, more than a fifth of the population has downloaded COVID-Tracker. And, on the other side of Mont Blanc, nearly two million Swiss have settled SwissCovid, while the country has less than 9 million inhabitants.

In Germany, Corona-Warn-App has 15 million active users. However, there too, the effectiveness of contact tracing via mobile is limited even if, every day, thousands of Germans are alerted, against a few hundred in France. In October, only 3% of positive cases were reported on the application across the Rhine.

Still anecdotal or still promising? For technician Baptiste Robert, “the concept of contact tracing via a mobile app looks great on paper. In practice, it does not work ”. The biostatistics researcher is not so blunt: “Of course, we are still far from sufficient use, but we must remember that in theory, if everyone used it daily, we would no longer need the confinement. “. The coming weeks of easing restrictions will undoubtedly be decisive in judging the success of the device.