During a pandemic such as COVID-19, mitigating the spread of infections is essential in the absence of a vaccine and limited critical care resources.
In a new study, authors shown that face mask use in the general population can have a beneficial impact in reducing the total number of cases and deaths, and that this impact naturally increases with mask effectiveness. Face mask use is common in East and South East Asia, and is currently recommended by the government in China, Hong Kong and Taiwan for healthy persons in crowded public spaces, as well as for symptomatic persons in Japan and Singapore. Besides, face mask use was compulsory in public in Wuhan, China, during public lockdown at the height of the epidemic.
The benefits of mask deployment are apparent even with low effectiveness ―such as N95 masks, more effective than surgical masks―, and limited resources. In such cases, though mask deployment may not have a large impact on total cases and deaths, indirect benefits for outbreak management are achieved by delaying the epidemic peak. Importantly, however, the overall impact of mask deployment hinges on appropriate distribution strategies.
In this way, authors consistently observed that the random distribution of masks throughout the general population is a suboptimal strategy. In contrast, prioritizing the elderly population, and retaining a supply of masks for identified infectious cases generally leads to a larger reduction in total infections and deaths than a naive allocation of resources. While there remains much uncertainty around the true effectiveness of face masks ―especially when factoring in differences in mask types, levels of adherence and patterns of human behavior―, there is evidence to suggest that masks can provide a measure of protection and containment for respiratory viruses, likely a greater degree of the latter than the former.
In addition, the more effective a mask is, the fewer masks are required to suppress an epidemic. Under a strategy in which masks are retained for infectious persons, this is particularly important. As a higher proportion of infectious persons ―both symptomatic and asymptomatic (and possibly unaware of their status as a carrier)―, are wearing masks offering a high level of containment, a smaller number of onward transmissions occur, requiring fewer masks to be provided for newly diagnosed individuals.
While mask use can help to mitigate transmission, the supply and demand model suggests that panic buying at the very early phase of an epidemic can be detrimental, and that managing demand in the early stages of the outbreak could be beneficial (in Taiwan, the government implemented such a resource management strategy in early February 2020, limiting the number of masks each person can buy per week with their National Health Insurance cards).
Finally, as human behavior and compliance are a significant component of how effective mask use is, it is essential that public health recommendations concerning face masks in the general population occur in tandem with clear education on proper use and application, such that limited resources are used as effectively as possible.
Link to the paper: https://doi.org/10.1101/2020.04.04.20052696
Editorial Disclaimer: information published during the 2020 COVID-19 pandemic may be updated frequently to reflect the dynamic nature of current understanding.