LoneWalker wrote: ↑Sun Oct 04, 2020 12:37 pm
A 2019 World Health Organization review of numerous studies testing the efficacy of face coverings to stop the transmission of influenza found "no evidence that [wearing a mask] is effective in reducing transmission" of the virus.
The organization has further discouraged individuals from using cloth masks to cover their faces during pandemics, though at times that advice has appeared to shift.The 2019 review was part of a larger study examining "
non-pharmaceutical public health measures for mitigating the risk and impact of epidemic and pandemic influenza."
That paper effected a "systematic review of the evidence on the effectiveness of [non-pharmaceutical interventions], including personal protective measures, environmental measures, social distancing measures and travel-related measures."
https://justthenews.com/politics-policy ... dence-they
I graduated from SFSU, Biology 1974. We learned in our first round of lab work to use the ventilator / pull down shield. Why? Face masks are only reliable until the exhaled moisture inside the mask builds up and reaches the exterior side of the mask.
At that point, about 20 minutes in non-stress conditions, there are channels to the surrounding environment. In other words, the moist air sitting inside the mask makes an excellent conduit for whatever is outside the mask.
So, there is nothing new about this mask thing; well, except, it's been politicized as a Dem weapon.
On the other hand, respirators do work if they have the correct filters.