COVID-19 contact tracing apps in Europe, technological feat or failure?

Abstract Background In the context of infectious disease control (IDC), public health services (PHS) have been under great pressure during the COVID-19 pandemic, especially with the burden of contact tracing. Most European Union countries have developed contact tracing apps for smartphones (CTA) with the goal of aiding PHS in IDC. CTAs generally use proximity data from mobile devices to determine a user's risk of exposure to SARS-CoV-2, thus providing testing and isolation recommendations. This review aimed to study the acceptance and adoption of CTAs in Europe. Methods 5 European countries were selected: Germany, Spain, France, Ireland, Italy. A literature review was carried out and official sources of information from each country were consulted in order to compare the adoption of each national CTA. Criterias included number of downloads, rating in the app stores, costo of development, proportion of positive tests registered. Potential factors influencing population adherence to CTAs were also investigated. Results In proportion to their population, the number of downloads varied significantly in each country (18 % in Spain, 67% in France, 75% in Ireland). Except for Spain, all countries integrated additional functions into the CTA to increase its uptake, such as access to the vaccination certificate. App stores ratings ranged from 3.0 (Spain) to 3.9 (France and Ireland). The proportion of tests added in the apps varied significantly (1% in Italy and Spain, 4% in Ireland, 10% in France and 17% in Germany). Concerns that lead to the non-use of CTAs were related to data protection, smartphone battery drainage and app bugs. Conclusions CTAs as a way to identify contacts from a positive case had a low impact in the analyzed countries, with low population adherence being an important factor. Adding more features within the apps, minimizing bugs, and increasing public confidence in data privacy seem essential to increase uptake in the future. Key messages Although conceptually attractive, CTAs have not proven to be effective in the context of the COVID-19 pandemic. There is a need for research and evaluation of the use of CTA, including cost effectiveness metrics, to inform future implementation similar technologies.


Background:
The last three decades have seen the development of chemsex, the diversification of substances through New Psychoactive Substances (NPS), and new technologies allowing people to buy online and find peers to consume on applications while remaining in private spheres (Trend, Cadet-Taillou, 2020). The latter has made it more difficult to reach users, so as to document their uses and the population, and to design public health schemes aimed at users, except through targeting metapopulations known to consume more than the general population (Léobon et al., 2018;Talley et al., 2011).

Methods:
The PlaySafe association designed two dummy websites, one selling GBL, the other NPS. These websites use the same graphics and syntactic codes as the main websites of the field, except for: 1) a fake drug named ''love machine''; 2) an automatic redirection to a health promotion page instead of payment finalization. The information collected is: delivery region, birth year, gender, perceived usefulness of the health promotion messages, whether people would recommend to friends, the contents and quantities of the shopping cart, the time spent on each page, and data gathered via Google Analytics.

Results:
On both websites 21,459 order attempts have been placed. This pathfinder research project has allowed to reach 6,203 people on the GBL website in 30 months and 7,927 people in 12 months on the NPS website, with people spending on average 1 min 35 s on the first website's prevention page and 1 min 27 s on the second. Around 85% of people consider the content useful, among whom 75% would recommend the website to friends. This communication also aims to present the characteristics of the reached population.

Conclusions:
This innovative approach has allowed to precisely target a population escaping public health research and prevention schemes. It appears interesting to explore online prevention, especially since most of the respondents consider the experience helpful and recommendable. Key messages: NTIC can serve research and actions in public health in order to reach online drug buyers.
Monitoring the online drug market can be used to design actions by stakeholders.

Background:
In the context of infectious disease control (IDC), public health services (PHS) have been under great pressure during the COVID-19 pandemic, especially with the burden of contact tracing. Most European Union countries have developed contact tracing apps for smartphones (CTA) with the goal of aiding PHS in IDC. CTAs generally use proximity data from mobile devices to determine a user's risk of exposure to SARS-CoV-2, thus providing testing and isolation recommendations. This review aimed to study the acceptance and adoption of CTAs in Europe.

Methods:
5 European countries were selected: Germany, Spain, France, Ireland, Italy. A literature review was carried out and official sources of information from each country were consulted in order to compare the adoption of each national CTA. Criterias included number of downloads, rating in the app stores, costo of development, proportion of positive tests registered. Potential factors influencing population adherence to CTAs were also investigated.

Results:
In proportion to their population, the number of downloads varied significantly in each country (18 % in Spain, 67% in France, 75% in Ireland). Except for Spain, all countries integrated additional functions into the CTA to increase its uptake, such as access to the vaccination certificate. App stores ratings ranged from 3.0 (Spain) to 3.9 (France and Ireland). The proportion of tests added in the apps varied significantly (1% in Italy and Spain, 4% in Ireland, 10% in France and 17% in Germany). Concerns that lead to the non-use of CTAs were related to data protection, smartphone battery drainage and app bugs.

Conclusions:
CTAs as a way to identify contacts from a positive case had a low impact in the analyzed countries, with low population adherence being an important factor. Adding more features within the apps, minimizing bugs, and increasing public confidence in data privacy seem essential to increase uptake in the future. Key messages: Although conceptually attractive, CTAs have not proven to be effective in the context of the COVID-19 pandemic.
There is a need for research and evaluation of the use of CTA, including cost effectiveness metrics, to inform future implementation similar technologies.