On the Effectiveness of Digital Contact Tracing and Contact Prevention Under Varying COVID-19 Infection Detection Rates

Background: A plethora of measures are being combined in the attempt to reduce SARS-CoV-2 spread, which arguably remains uncontrolled as of December 2020. Amongst mitigation measures available, only a few have the potential to be sustainable over long periods of time. Among these, contact tracing (CT)is being applied in many countries with varying degrees of success.Methods: We analyze the infection detection rate and time delay dependency of CT, as well as the effective-ness of a novel strategy, community-based privacy-preserving contact prevention (CP). To assess and compare CT and CP, we model their effect on contagion dynamics in SERIA, a highly detailed agent-based simulation platform which implements realistic population-dependent statistical distributions.Findings: Diagnostic/isolation delays and poor testing (low infection detection rates) greatly impair the ability of CT strategies to reduce viral propagation. For countries already applying measures such as widespread mask use and self-isolation upon symptom onset, applying a combination of CT and CP could reduce the final epidemic size from 47-55% to 26-42%, as well as reduce pandemic-related mortality by a factor of 1.4-2.3 depending on infection detection and app adoption rates.Interpretation: CP is an appealing complement to CT, particularly in scenarios where infection detection rate is low. CP and CT are plausible tools for sustainably reducing the propagation of respiratory viruses while relying on available technology, respecting data privacy, and most importantly, promoting community-based awareness and social responsibility. The combination of both strategies is a promising strategy to minimize the impact of the COVID-19 and future pandemics.Funding: National Agency for the Promotion of Research, Technological Development and Innovation (I+D+I Agency), Ministry of Science, Technology and Productive Innovation of Argentina.Declaration of Interests: We declare no competing interests.