MD: Etude chinoise sur l' impact du port de masque dans la population, via des projections épidémiologiques, avec 65% de diminution de mortalité attendue si 15% de la population portait un masque empêchant 75% de passage des flux d’air (les masques chirurgicaux ayant une efficacité minimale réglementaire de 78%). Ils montrent aussi qu’en cas de faible ressource en masque, la distribution préférentielle aux personnes à risque de forme sévère comparativement à une distribution réservée aux patients symptomatiques avait un plus fort impact sur la mortalité (probablement en raison de l’importance des cas asymptomatique, la protection en « bout de la chaîne » prévalant alors)
The ongoing novel coronavirus disease (COVID-19) pandemic has rapidly spread in early 2020, causing tens of thousands of deaths, over a million cases and widespread socioeconomic disruption. With no vaccine available and numerous national healthcare systems reaching or exceeding capacity, interventions to limit transmission are urgently needed. While there is broad agreement that travel restrictions and closure of non-essential businesses and schools are beneficial in limiting local and regional spread, recommendations around the use of face masks for the general population are less consistent internationally. In this study, we examined the role of face masks in mitigating the spread of COVID-19 in the general population, using epidemic models to estimate the total reduction of infections and deaths under various scenarios. In particular, we examined the optimal deployment of face masks when resources are limited, and explored a range of supply and demand dynamics. We found that face masks, even with a limited protective effect, can reduce infections and deaths, and can delay the peak time of the epidemic. We consistently found that a random distribution of masks in the population was a suboptimal strategy when resources were limited. Prioritizing coverage among the elderly was more beneficial, while allocating a proportion of available resources for diagnosed infected cases provided further mitigation under a range of scenarios. In summary, face mask use, particularly for a pathogen with relatively common asymptomatic carriage, can effectively provide some mitigation of transmission, while balancing provision between vulnerable healthy persons and symptomatic persons can optimize mitigation efforts when resources are limited.
