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I'm curious, I've been seeing a lot of calls for 3D printing similar looking Face shields, which are very different from face masks. What is the use for this? A

I'm curious, I've been seeing a lot of calls for 3D printing similar looking Face shields, which are very different from face masks. What is the use for this? Are they actually useful to health care professionals? Face mask + goggles fully covers the 3 places the virus can enter (mouth, nose and eyes), but these shields seem like they would be more useful for people who have the virus than those who don't.

zimpenfish 7y ago
> Face mask + goggles fully covers the 3 places the virus can enter (mouth, nose and eyes) I believe face masks are only 95% effective at best and that's only with a proper N95 which a lot of medical staff appear not to be able to get hold of. Hence they're wearing things like Buffs or cycling masks to make do. In that situation, having another layer that can stop droplets etc. from reaching the mask in the first place makes sense to me. Plus it stops a whole lot of messy body fluids from reaching the mask and goggles which cuts out a swap/clean cycle (again, difficult if there's no spares!) [Edit to correct 'googles' to 'goggles', FFHS]
- varenc 7y ago
  An N95 respirator is rated to block at least 95% of 0.3 μm particles. It’ll do waaay better than 95% at blocking droplets! They’re much larger. (though N99 and N100 respirators do exist)
  - stubish 7y ago
    But remember that a respirator blocks 0% of particles getting in your eyes.
- ehsankia 7y ago
  I see, so are they wearing these shields on top of the usual mask?
disillusioned 7y ago
Face shields provide specific protection against bodily fluids: sneezes, blood sprays, etc., that would further soil the masks you wear underneath them. This study talks through the advantages of adding them to the repertoire for infectious disease control as part of your PPE: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5015006/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5015006/
neuronic 7y ago
COVID-19 is very likely only marginally spread by aerosols (I take this from Robert Koch Institute, Germany information [1]), approximately 10% by contact spread and mainly by direct transmission of droplets. Faceshield therefore protects from the main transmission vector. It's not impossible to get infected otherwise, simply much less likely. Your main enemy are getting coughed/sneezed/talked at in close proximity. Surface spread is likely also extremely limited (source: Prof. Hendrik Streecke who continues to study COVID-19 in the German epicenter of Heinsberg [2]). Money quote from source: > "Wir waren in einem Haushalt, wo viele hochinfektiöse Menschen gelebt haben, und trotzdem haben wir kein lebendes Virus von irgendeiner Oberfläche bekommen.“ English: "We have studied a household where highly infectious individuals resided and have still been unable to find any living virus on any surface." All virus residues found have been dead virus material. [1, German] https://www.rki.de/DE/Content/InfAZ/N/Neuartiges_Coronavirus/Steckbrief.html https://www.rki.de/DE/Content/InfAZ/N/Neuartiges_Coronavirus... [2, German] https://www.deutschlandfunk.de/covid-19-wie-lange-sich-das-coronavirus-auf-oberflaechen.2850.de.html?drn:news_id=1116563 https://www.deutschlandfunk.de/covid-19-wie-lange-sich-das-c...
- harimau777 7y ago
  So this is likely a dumb idea, but if things got truly desperate I wonder if a snorkel mask would be a decent improvised protection. Your eyes and nose would be completely covered and your mouth is getting air from a direction/location that is unlikely to be in the "line of fire" from someone coughing or sneezing.
  - dmurray 7y ago
    Definitely. A snorkel/scuba mask is going to be better protection than most masks, though relatively expensive to produce and clean and can't be treated as disposable.
  - londons_explore 7y ago
    But if you have to breathe in infected air, doing so with your nose is far better than your mouth, since your nasal cavity has thicker membranes and a lot of mucus and hairs to catch particles, whereas through your mouth the particles are going straight into your lungs. In fact, that effect might be so significant evolutionationary that it is the reason we have a seperate nose and mouth, rather than combining the two.

zimpenfish 7y ago

> Face mask + goggles fully covers the 3 places the virus can enter (mouth, nose and eyes) I believe face masks are only 95% effective at best and that's only with a proper N95 which a lot of medical staff appear not to be able to get hold of. Hence they're wearing things like Buffs or cycling masks to make do. In that situation, having another layer that can stop droplets etc. from reaching the mask in the first place makes sense to me. Plus it stops a whole lot of messy body fluids from reaching the mask and goggles which cuts out a swap/clean cycle (again, difficult if there's no spares!) [Edit to correct 'googles' to 'goggles', FFHS]

varenc 7y ago
An N95 respirator is rated to block at least 95% of 0.3 μm particles. It’ll do waaay better than 95% at blocking droplets! They’re much larger. (though N99 and N100 respirators do exist)
- stubish 7y ago
  But remember that a respirator blocks 0% of particles getting in your eyes.
ehsankia 7y ago
I see, so are they wearing these shields on top of the usual mask?

disillusioned 7y ago

Face shields provide specific protection against bodily fluids: sneezes, blood sprays, etc., that would further soil the masks you wear underneath them. This study talks through the advantages of adding them to the repertoire for infectious disease control as part of your PPE: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5015006/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5015006/

neuronic 7y ago

COVID-19 is very likely only marginally spread by aerosols (I take this from Robert Koch Institute, Germany information [1]), approximately 10% by contact spread and mainly by direct transmission of droplets. Faceshield therefore protects from the main transmission vector. It's not impossible to get infected otherwise, simply much less likely. Your main enemy are getting coughed/sneezed/talked at in close proximity. Surface spread is likely also extremely limited (source: Prof. Hendrik Streecke who continues to study COVID-19 in the German epicenter of Heinsberg [2]). Money quote from source: > "Wir waren in einem Haushalt, wo viele hochinfektiöse Menschen gelebt haben, und trotzdem haben wir kein lebendes Virus von irgendeiner Oberfläche bekommen.“ English: "We have studied a household where highly infectious individuals resided and have still been unable to find any living virus on any surface." All virus residues found have been dead virus material. [1, German] https://www.rki.de/DE/Content/InfAZ/N/Neuartiges_Coronavirus/Steckbrief.html https://www.rki.de/DE/Content/InfAZ/N/Neuartiges_Coronavirus... [2, German] https://www.deutschlandfunk.de/covid-19-wie-lange-sich-das-coronavirus-auf-oberflaechen.2850.de.html?drn:news_id=1116563 https://www.deutschlandfunk.de/covid-19-wie-lange-sich-das-c...

harimau777 7y ago
So this is likely a dumb idea, but if things got truly desperate I wonder if a snorkel mask would be a decent improvised protection. Your eyes and nose would be completely covered and your mouth is getting air from a direction/location that is unlikely to be in the "line of fire" from someone coughing or sneezing.
- dmurray 7y ago
  Definitely. A snorkel/scuba mask is going to be better protection than most masks, though relatively expensive to produce and clean and can't be treated as disposable.
- londons_explore 7y ago
  But if you have to breathe in infected air, doing so with your nose is far better than your mouth, since your nasal cavity has thicker membranes and a lot of mucus and hairs to catch particles, whereas through your mouth the particles are going straight into your lungs. In fact, that effect might be so significant evolutionationary that it is the reason we have a seperate nose and mouth, rather than combining the two.