To combat the first wave of the COVID-19 pandemic, many European countries instituted a strict lockdown coupled with reverse-transcription polymerase chain reaction (RT-PCR) testing, which led to a relative decline in case fatality [1]. These countries also developed a public health strategy involving the use of digital contact tracing (DCT) applications to improve timely tracking and contact tracing [2,3]. Despite these measures, the second epidemic wave occurred in autumn 2020, more rapidly and with a higher severity than expected, leading to a second lockdown in many countries. France developed a national “Test, Trace and Isolate” strategy, but did not achieve its goal of less than 5000 confirmed COVID-19 cases per day by December 15, 2020. As of that date, incidence had increased, and a curfew went into effect first. Several weeks later, in facing a third wave, a lockdown was reinstituted by many countries.

France’s independent COVID-19 Control and Society Connection Council (CCL) was established by law in May 2020 in order to issue advice and recommendations on the national epidemic digital systems. The CCL comprises 13 members, including representatives from the parliament and civil society, patient organizations, jurists, and academics from different disciplines (see Multimedia Appendix 1 [4]). Considering the characteristics of European DCT apps and their potential, we present the CCL’s recommendations, with the objective to increase the uptake and utility of French DCT apps. As the country's most vulnerable population has been subjected to greater virus exposure, a stronger impact of the lockdown, and less access to preventive and health care services, the CCL is particularly aware of prevailing health inequalities.

Several mobile apps for contact tracing and information on public health policy have been developed in Europe (Table 1). These apps should respond to scientifically valid and time-bound ethical guidelines. Insufficient privacy protection could erode trust in the government and public health services [5,6]. Unfortunately, adoption of these apps has been below expectations [7]; although, adoption has been high in Finland (45%), it has been limited elsewhere (24% in Ireland, 21% in Switzerland, 19% in Germany, and 13% in Italy [8]; see Table 1). The French DCT StopCovid app was based on Bluetooth-based exposure notification. Conceived as a silent app (ie, without interactivity), it was replaced on October 22, 2020, by a conversational app renamed TousAntiCovid. Among 66 million inhabitants, only 1.5 million (2.3%) had downloaded the StopCovid app and, as of March 2021, this number increased to 13.6 million (ie, 20% of the French population). Moreover, positive test declarations (n=183,377), such as notifications of a contact (n=107,465) have been weak. The poor results of the StopCovid app stemmed from the lack of attractiveness and prevention information, a fear of insufficient privacy protection, Bluetooth connection problems, and the incompatibility of apps with older smartphones.

To promote the use of the apps, the CCL recommended increasing the communication about the individual and collective objectives of the TousAntiCovid app. The CCL also recommended the introduction of clear, simple, accessible, incentivizing, noncoercive information in the digital tool. Indeed, the messages aimed at emphasizing risk are less effective than those encouraging self- and collective efficacy [9]. Moreover, to stimulate DCT uptake, apps should enhance perceived benefits [10]. In addition, the CCL recommended improving public health policies to address the needs of the underprivileged population [11]. It bears mentioning that apps are effective only if users are comfortable with digital tools; technical problems are among the main reasons for failure to download [12]. It is also worth noting that the COVID-19 pandemic has accelerated digital health uptake: 49% of the French population used their first health digital tool during the first lockdown [13], whereas 16% of French population never connect to internet [14].

The CCL believes that the national “Test, Trace and Isolate” strategy needed consistency—testing without effective tracing and efficient isolation of positive cases makes little, if any, sense. In Europe and France, apps have progressively incorporated an isolation module (questions about needs during isolation). Their development should be aimed at measuring isolation prescription and adherence. Apps could help families to stay connected and maintain links to resources that support their physical and mental well-being [15]. Despite contrasting strategies of lockdown, no dramatic difference in the magnitude of the second epidemic wave seems to have been observed among these countries (Table 1). For persons with positive test results, the strategy adopted in most countries included a mandatory 7-day isolation until newer variants of SARS-CoV-2 were discovered [16].

There are several challenges in motivating populations to download DCT apps, even though it is a promising tool. Between European policies of isolation, which are either strict and instituted by national regulations with severe fines or based on incentives, the CCL recommends an intermediate position with national guidelines accompanied by strong incentive supports, ensuring good adherence from the population and avoiding the weakening of the “testing and contact tracing” facets of the national strategy. However, apps will not by themselves resolve the problem of isolation nonadherence, particularly among persons who are outside the health care system. The CCL recommends adaptations of the informational process for these persons. With regard to those for whom pragmatic isolation is difficult, because of home overcrowding, family composition, or work needs, the CCL recommends a prosocial approach with community officers who ensure that sufficient supplies (eg, essentials such as food, medication, and childcare resources) are provided [18].

To conclude, the CCL calls for promoting empowerment of the population with digital tools, improving public health culture for decision-makers dealing with health determinants, taking social considerations into account, and incorporating community participation [19].