“The contribution of digital contact tracing to epidemic mitigation remains limited”

Rome, March 26 (beraking latest news Health) – Manual tracking is more effective than that of Apps to identify ‘superspreaders’, i.e. asymptomatic individuals infected with Covid 19 who have many contacts. This is the result of the study conducted by a team of researchers from the University of Parma and the Imem and Isc institutes of the CNR published in ‘Nature Communications’ which reveals a crucial element for determining the effectiveness of contact tracing procedures for the containment of current pandemic.

Contact tracing procedures usually follow two paths: manual contact tracing, based on interviews made by healthcare personnel for the reconstruction of the contagion chains, and digital tracing, which uses Apps installed on smartphones. The two procedures sample contacts differently. The new study, conducted by Raffaella Burioni, professor at the Department of Mathematical, Physical and Computer Sciences of the University of Parma, Marco Mancastroppa, PhD student in Physics at the University of Parma, Alessandro Vezzani of the Imem Cnr of Parma and Claudio Castellano of Isc -Cnr of Rome, analyzed the effectiveness of the two strategies in an epidemic spread model with the empirical parameters describing the propagation of Sars-cov-2.

The results show that, even assuming a high diffusion of the digital app in the population, the contribution of digital contact tracing to the mitigation of the epidemic remains limited, while the manual procedure is very effective. This, according to what emerges from the study, occurs precisely because of the intrinsic difference in the way in which the two strategies sample the population and which has very relevant effects when, as in the case of the current pandemic, there are individuals with a large number of contacts.

The difference is clear considering what happens with an asymptomatic infected individual who has had many contacts, a ‘superspreader’: with the manual procedure it is very likely that some of his many contacts will remember the encounter and thus allow him to be identified; with digital contact tracing, if the superspreader does not use the App it is not possible in any way to trace him. This result will allow to evaluate in detail the strengths and weaknesses of the two strategies and opens the way to the identification of optimal hybrid contact tracing strategies.