The advantage of self-protecting interventions in mitigating epidemic circulation at the community level

TL;DR

This study demonstrates that self-protecting interventions, like masks that primarily protect the wearer, are more effective at reducing epidemic spread than contact-protecting measures, especially when implemented at the community level.

Contribution

The paper provides analytical and simulation evidence showing the superior effectiveness of self-protecting interventions over contact-protecting ones in epidemic mitigation.

Findings

Self-protecting interventions reduce disease prevalence more effectively.

Interventions protecting the wearer outperform those protecting contacts.

Results hold across simple and realistic epidemic models.

Abstract

Protecting interventions of many types (both pharmaceutical and non-pharmaceutical) can be deployed against the spreading of a communicable disease, as the worldwide COVID-19 pandemic has dramatically shown. Here we investigate in detail the effects at the population level of interventions that provide an asymmetric protection between the people involved in a single interaction. Masks of different filtration types, either protecting mainly the wearer or the contacts of the wearer, are a prominent example of these interventions. By means of analytical calculations and extensive simulations of simple epidemic models on networks, we show that interventions protecting more efficiently the adopter (e.g the mask wearer) are more effective than interventions protecting primarily the contacts of the adopter in reducing the prevalence of the disease and the number of concurrently infected individuals ("flattening the curve"). This observation is backed up by the study of a more realistic epidemic model on an empirical network representing the patterns of contacts in the city of Portland. Our results point out that promoting wearer-protecting face masks and other self-protecting interventions, though deemed selfish and inefficient, can actually be a better strategy to efficiently curtail pandemic spreading.