Measuring close proximity interactions in summer camps during the COVID-19 pandemic

TL;DR

This study introduces a novel high-precision method using UWB radios combined with Bluetooth to accurately measure close proximity interactions among children and educators in summer camps, providing detailed data to inform COVID-19 mitigation strategies.

Contribution

The paper presents the Janus system, a new approach that combines UWB and Bluetooth radios for precise in-field contact data collection, enabling advanced risk analysis in social environments.

Findings

Collected detailed contact data in summer camps during COVID-19

Identified behaviors and activities associated with higher transmission risk

Evaluated effectiveness of social bubbles and activity organization in reducing risk

Abstract

Policy makers have implemented multiple non-pharmaceutical strategies to mitigate the COVID-19 worldwide crisis. Interventions had the aim of reducing close proximity interactions, which drive the spread of the disease. A deeper knowledge of human physical interactions has revealed necessary, especially in all settings involving children, whose education and gathering activities should be preserved. Despite their relevance, almost no data are available on close proximity contacts among children in schools or other educational settings during the pandemic. Contact data are usually gathered via Bluetooth, which nonetheless offers a low temporal and spatial resolution. Recently, ultra-wideband (UWB) radios emerged as a more accurate alternative that nonetheless exhibits a significantly higher energy consumption, limiting in-field studies. In this paper, we leverage a novel approach, embodied by the Janus system that combines these radios by exploiting their complementary benefits. The very accurate proximity data gathered in-field by Janus, once augmented with several metadata, unlocks unprecedented levels of information, enabling the development of novel multi-level risk analyses. By means of this technology, we have collected real contact data of children and educators in three summer camps during summer 2020 in the province of Trento, Italy. The wide variety of performed daily activities induced multiple individual behaviors, allowing a rich investigation of social environments from the contagion risk perspective. We consider risk based on duration and proximity of contacts and classify interactions according to different risk levels. We can then evaluate the summer camps' organization, observe the effect of partition in small groups, or social bubbles, and identify the organized activities that mitigate the riskier behaviors. [...]