Earlier quoted context omitted.
> Remember what the official word was for all too long: masks don't work, but save them for health workers. Who said masks don't work? What I recall people saying is: * most masks provide marginal protection to the wearer * the masks that provide effective protection should be saved for those in situations where they need them (and can be knowledgeably used) * most people probably don't need those masks There's a wor…
The CDC and WHO both at various times recommended against the general public wearing masks. https://www.vox.com/recode/2020/4/13/21214114/media-coronavi... This advice was wrong. It is not just sick people that benefit from wearing masks. It is not true that people are flattening that into "masks don't work". Masks don't work was repeated many, many times by these organizations. Here's an example: https://www.cidrap.…
"We do not recommend requiring the general public who do not have symptoms of COVID-19-like illness to routinely wear cloth or surgical masks because:
"There is no scientific evidence they are effective in reducing the risk of SARS-CoV-2 transmission
"Their use may result in those wearing the masks to relax other distancing efforts because they have a sense of protection
"We need to preserve the supply of surgical masks for at-risk healthcare workers.
"Sweeping mask recommendations—as many have proposed—will not reduce SARS-CoV-2 transmission, as evidenced by the widespread practice of wearing such masks in Hubei province, China, before and during its mass COVID-19 transmission experience earlier this year. Our review of relevant studies indicates that cloth masks will be ineffective at preventing SARS-CoV-2 transmission, whether worn as source control or as PPE.
"Surgical masks likely have some utility as source control (meaning the wearer limits virus dispersal to another person) from a symptomatic patient in a healthcare setting to stop the spread of large cough particles and limit the lateral dispersion of cough particles. They may also have very limited utility as source control or PPE in households."
Note the word in the first sentence: "requiring".
The article then goes on to describe filter fit and efficiency.
"These studies demonstrate that cloth or homemade masks will have very low filter efficiency (2% to 38%). Medical masks are made from a wide range of materials, and studies have found a wide range of filter efficiency (2% to 98%), with most exhibiting 30% to 50% efficiency.6-12"
"In sum, given the paucity of information about their performance as source control in real-world settings, along with the extremely low efficiency of cloth masks as filters and their poor fit, there is no evidence to support their use by the public or healthcare workers to control the emission of particles from the wearer."
As well as surgical masks...
"There is no evidence that surgical masks worn by healthcare workers are effective at limiting the emission of small particles or in preventing contamination of wounds during surgery.
"There is moderate evidence that surgical masks worn by patients in healthcare settings can lower the emission of large particles generated during coughing and limited evidence that small particle emission may also be reduced."
And N95 respirators...
"In summary, N95 FFRs on patients will not be effective and may not be appropriate, particularly if they have respiratory illness or other underlying health conditions. Given the current extreme shortages of respirators needed in healthcare, we do not recommend the use of N95 FFRs in public or household settings."
And in conclusion:
"While this is not an exhaustive review of masks and respirators as source control and PPE, we made our best effort to locate and review the most relevant studies of laboratory and real-world performance to inform our recommendations. Results from laboratory studies of filter and fit performance inform and support the findings in real-world settings.
"Cloth masks are ineffective as source control and PPE, surgical masks have some role to play in preventing emissions from infected patients, and respirators are the best choice for protecting healthcare and other frontline workers, but not recommended for source control. These recommendations apply to pandemic and non-pandemic situations.
"Leaving aside the fact that they are ineffective, telling the public to wear cloth or surgical masks could be interpreted by some to mean that people are safe to stop isolating at home. It's too late now for anything but stopping as much person-to-person interaction as possible.
"Masks may confuse that message and give people a false sense of security. If masks had been the solution in Asia, shouldn't they have stopped the pandemic before it spread elsewhere?"
All of this is backed up with a goodly stack of references. Which part do you consider dead wrong, and based on what?