3 ms·
The review found very few studies into the effectiveness of N95/respirators against ILIs, and from those studies they concluded "wearing N95/P2 respirators prob
by mike_hearn 3y ago
The review found very few studies into the effectiveness of N95/respirators against ILIs, and from those studies they concluded "wearing N95/P2 respirators probably makes little to no difference".
Bear in mind a possible source of confusion here: TB bacterium are ~3 microns in size, but viruses are about 0.2 microns. The Cochrane review I mentioned is only about respiratory viruses. So it's possible that they may work against TB but not against flu or COVID.
- classichasclass 3y agoI'm pretty aware of how large a TB bacillus is, thanks. The NIOSH definition for an N95 is a device able to filter at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers. While SARS-CoV-2 is around 0.1 microns in size, naked COVID-19 viruses in air are rare as they would be torn up nearly immediately, so they are almost always within aerosols. Typical respiratory aerosol range is around half a micron or so [0], and as the aerosol particle size gets smaller, so necessarily must be the amount of virus that is present. Is this perfect filtration? No, but no one gets sick from a single virus they inhaled either, even with as communicable as the current Omicron variants are. There's a minimum infective dose and they help keep exposure under it. [0] https://www.nature.com/articles/s43856-022-00103-w https://www.nature.com/articles/s43856-022-00103-w
- vibrio 3y agoThe size of the single virus is a false metric here. There is a wide range of respiratory droplets containing virions. Those droplets can range from visible (way bigger than a mycobacterium ) to only large enough to hold one virion. The size distribution of those particles is the metric.