The Role of Masks in Mitigating Viral Spread on Networks

Tian, Yurun; Sridhar, Anirudh; Poor, H.Vincent; Yagan, Osman

Masks have remained an important mitigation strategy in the fight against COVID-19 due to their ability to prevent the transmission of respiratory droplets between individuals. In this work, we provide a comprehensive quantitative analysis of the impact of mask-wearing. To this end, we propose a novel agent-based model of viral spread on networks where agents may either wear no mask, or wear one of several types of masks with different properties (e.g., cloth or surgical). We derive analytical expressions for three key epidemiological quantities: the probability of emergence, the epidemic threshold, and the expected epidemic size. In particular, we show how the aforementioned quantities depend on the structure of the contact network, viral transmission dynamics, and the distribution of the different types of masks within the population. We then investigate the impact of different allocations of masks within the population through extensive simulations. We also investigate tradeoffs between masks with high outward efficiency but low inward efficiency and masks with high inward efficiency but low outward efficiency. Interestingly, we find that the former type of mask is most useful for controlling the spread in the early stages of an epidemic, while the latter type is most useful in mitigating the impact of an already large spread.