How Misinformation that Facemasks are Effective for Reducing COVID-19 is Transmitted

Abstract

J Neurol Neurocrit Care, Volume 3(2): 1–3, 2020 The evidence from randomized controlled trials (RCTs) that surgical facemasks and cloth facemasks are ineffective for preventing transmission of respiratory viruses in public is conclusive [1-8]. In all the meta-analyses of all the existing RCTs [4-7], not a single trial was found in which facemasks provided any protection against virus transmission in public [1,2]. Consistent with the findings of all RCTs comparing transmission rates in public with and without facemasks, Leung et al. compared the rates of detection of three types of viruses in exhalations by infected individuals with and without facemasks: they concluded that, with facemasks, there was: “no significant reduction in detection of influenza virus in aerosols;” “For rhinovirus there were no significant differences between detection of virus with or without facemasks, both in respiratory droplets and in aerosols;” and, for coronavirus there was “no significant reduction in detection in aerosols [3].” They did observe a reduction in detection of viruses in respiratory droplets for influenza virus and coronavirus. There is no doubt that facemasks can reduce the transmission of droplets, but droplets are not the concern for transmission of viruses in public. Significant numbers of droplets are not exhaled by asymptomatic carriers because they are not coughing or sneezing in public. Symptomatic carriers who are coughing and sneezing should be quarantined. The rationale for both recommended and mandated facemasks in public is to reduce transmission by asymptomatic carriers. Since all the RCTs in the literature show no reduction in transmission of viruses in public due to facemasks, one wonders why the CDC, NIH and virtually all medical authorities are stating that there is conclusive scientific evidence that facemasks reduce viral transmission in public.