Two recent publications conclude there are no differences between surgical masks and respirators for preventing person-to-person transmission of infectious respiratory viruses like SARS-CoV-2 and influenza. But these studies are deeply flawed.
One of these is a randomized controlled trial (RCT) by Loeb et al comparing SARS-CoV-2 infections in healthcare workers wearing respirators or masks for care of COVID-19 patients.1 The other is a Cochrane review by Jefferson et al of mask and respirator studies in households and healthcare settings.2
Both are built on the premise that infectious respiratory viruses like SARS-CoV, SARS-CoV-2, MERS-CoV, and influenza are only transmitted person to person by large droplets. This not true. The science is very clear that the predominant mode by which these viruses are transmitted person to person is inhalation of small particles, most of which are around 1 micrometer.3–13
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