On 28/03/2020 06:28, wrote:
When I go out, I see lots of people wearing masks. I also see medical
people wearing masks when dealing with COVID-19 cases. Why is this?
The BBC was unequivocal, at the start of this crisis, in stating that
masks are not useful as a preventive measure against COVID-19.

If we are talking about the typical "surgical mask", then my
understanding is that as a way of protecting you from catching it, they
are not that effective. (The filtration is poor, they typically leak at
the face seals, and they don't protect the mucous membranes of the eyes).

On medial staff, they can be effective in lowering the risks of passing
infection to your patients via droplets. However to use them
effectively, requires a level of discipline and training. i.e. changing
them between patients, not touching them and allowing contamination of
the hands etc, disposing of them as clinical waste and so on.

The might be some *very small* argument, that if everyone were wearing
them, they might reduce the amount of droplets projected into the air,
but I suspect that any advantage would be quickly lost in a non clinical
use pattern (e.g. wearing it all day, adjusting, removing, refitting
after eating and so on). Its even possible that you would increase risks
of infection as it would encourage more face touching, and more transfer
of the virus to hard surfaces that other people will then pick up, and
transfer to their face next time they touch their mask.

Was the BBC wrong, or lying?

IMO, no.


[1] To be effective protection for the wearer they would need full face
coverage, and much higher levels of filtration with the capacity to
filter vapour / chemical contamination as well as particulates. Also the
be assured of protection they would need to be properly fitted with a
proper respirator testing hood etc.



--
Cheers,

John.

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