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Conclusion must be changed regarding infection risk

Posted by msauaf on 22 May 2020 at 05:32 GMT

"Any type of general mask use is likely to decrease viral exposure AND infection RISK on a population LEVEL, in spite of imperfect fit and imperfect adherence"
"Surgical masks provided about TWICE as much protection as home made masks"...
Since surgical masks are NOT effective against INFECTION by Covid19, as demonstrated by many essays, what to say about "home made" EFFICIENCY to reduce "infection", worst, on a POPULATION level.

This study is indeed interesting as it demonstrates the comparative PF among mask types. But JUST THAT.

There´s NOTHING in it that indicate INFECTION chance, since THIS would depend on determining: 1) a "typical" amount to assume of Covids "per particle", 2) what Covid load should be assumed to effectively contaminate a person (and this may vary largely due to age, overall health status etc.) and 3) if the amount (not "volume") of ALL the contaminated particles that crossed the mask during ALL the test time (is reasonable to assume there is a 'recycling' of them, some inward are throwed back without touching wearer's mucosas) is enough (viral LOAD PEAK, in the test time) to infect the wearer or not.

So, definitely, no one has so far PROVEN "home made" masks "reduce" infection at POPULATION level. World health Organization remains right, there's no CIENTIFIC proof of this.

My understanding is that the stated study CONCLUSION MUST be CHANGED to REMOVE the "and infection risk" part. Anything covering aerial vias, well or not fit, will "reduce" "exposure" at SOME level, from 10e-5 to 100x, and this study has finely tackled how FPP and surgical masks compare to a TEA paper home made mask (not OTHER many more materials people may use, like "socks" or "t-shirts" for instance) in terms of exposure. But just that. NOT "infection" risk, since it was just a comparative study of PF not entering in the merit of how it impact viral load neither which load is assumed to infect.

No competing interests declared.

RE: Conclusion must be changed regarding infection risk

msauaf replied to msauaf on 22 May 2020 at 05:37 GMT

PS: all caps is not "shouing", I just use in place of italics where such feature is unavailable in the text editor of comments' field :)

No competing interests declared.

RE: Conclusion must be changed regarding infection risk

ToqueMidas replied to msauaf on 16 Nov 2021 at 21:07 GMT

Correct, without using infectious pathogenes, isn't possible to conclude that infectious pathogenes would be filter, the particules filtered ranged 50 times between extremes, between 0.02 µm–1 µm, so we can presume that only particules of 1 µm were filtered which are even twice as bigger than the bacteria Streptococcus pneumoniae. The experiment couldn't exclude the hypothesis that in the masks with less particules in the inside was not because the diference in filtration but instead because the more resistance to the flow of breathable air the subjects needed to produce more pressure which caused the particules that were inside the mask to get lose from the fibers and got in the respiratory system

No competing interests declared.