Following Guidelines

[gordo]

Gordo, the article you reference is from May. They've more recently posted a review from JAMA of the latest science and case studies that show that masks do prevent the spread of COVID19.

"CDC reviewed the latest science and affirms that cloth face coverings are a critical tool in the fight against COVID-19 that could reduce the spread of the disease, particularly when used universally within communities. There is increasing evidence that cloth face coverings help prevent people who have COVID-19 from spreading the virus to others."​

Coronavirus Disease 2019

CDC is closely monitoring an outbreak caused by a novel (new) coronavirus in Wuhan City, China.

www.cdc.gov

I would hardly call the anecdotal testimony of two hair dressers in a salon a science-based process for establishing policy.

To be effective, masks need to form an effective barrier against the virus. It does not matter if the virus is Covid19, Seasonal Flu, etc. Viruses have a specific micron size. Face masks are rated (among other things) to be barriers against particle size. E.g. they may be a barrier to dust or bacteria which are relatively large particles but be useless against smaller particles - like viruses.

AFAIK, there are no science-based studies that show consumer grade face masks being an effective barrier to viruses, like Covid 19. That's probably why the CDC initially said there was no need to wear them. And is also likely why the CDC didn't recommend the use of face masks during previous viral epidemics - like last year's seasonal season that killed some 80,000 US residents.

It is also why the quote you selected from JAMA report uses "weasel" words like: "could" and "help". The JAMA reports themselves do not reference science-based studies and make extensive use of another "weasel" word: "may". Weasel words, in legal (and marketing) parlance are used to suggest an affirmation when no affirmation can be made. Further, JAMA also included disclaimers about the validity of their report since it is not science-based and its methodology is severely flawed.

Take a close look at your face mask packaging. Here's one typical as an example (my emphasis):

That disclaimer is to prevent the vendor being sued if someone buys the mask believing that it offered any protection against Covid 19 - because it doesn't. You'll find similar wording on other consumer grade face masks since all manufacturers want to avoid litigation.

If you feel better by wearing a mask, then by all means wear one. Just don't expect it to do anything to protect you or others from the virus.

 

[AC Prepress]

AFAIK, there are no science-based studies that show consumer grade face masks being an effective barrier to viruses, like Covid

Face Masks Really Do Matter. The Scientific Evidence Is Growing.

Face masks are emerging as one of the most powerful weapons to fight the novel coronavirus, with growing evidence that facial coverings help prevent transmission—even if an infected wearer is in close contact with others.

www.wsj.com

 

[gordo]

Face Masks Really Do Matter. The Scientific Evidence Is Growing.

Face masks are emerging as one of the most powerful weapons to fight the novel coronavirus, with growing evidence that facial coverings help prevent transmission—even if an infected wearer is in close contact with others.

www.wsj.com

From the article - weasel words in bold:

"New research suggests that face coverings help reduce the transmission of droplets"
"facial coverings help prevent transmission"
"masks help reduce transmission"
"masks might offer some personal protection from the virus,"

These weasel words are used as a way to say something that legally, or truthfully, cannot be said. They imply an assertion when no assertion is actually made. Weasel words work by making you think you've read something that hasn't actually been written.

One of the studies cited comes with a disclaimer: "The study, which analyzed the droplet spread of a healthy volunteer after capturing it on video, hasn’t yet been peer-reviewed."

Another word that's used in the article is "believe". "Believing" is an opinion that is not based on objective reality. Many people believe in fairies - but that doesn't make fairies a reality.

"director of the Centers for Disease Control and Prevention, said he believes the pandemic could be brought under control over the next four to eight weeks"

"she believes some masks can likely filter out a majority of large viral droplets."

"She believes that, excluding N95 masks, multilayered masks with a slightly waterproof outer layer best minimize spread."

"Stanford researchers believe can better prevent virus particles" I italicized "better" because that's another weasel. "Better" suggests a quantitative amount but does not actually specify the amount. The word is meaningless.

Then there is the outright confused statement:
"The CDC doesn't recommend face shields for everyday activities or as a substitute for masks, citing a lack of evidence of their effectiveness for reducing Covid-19 spread." So, there's a lack of evidence of the effectiveness of face shields for reducing Covid-19 spread. Great. But in the next sentence (ignoring the weasel word):
"During a simulation, researchers found that wearing a face shield helped reduce exposure to an influenza-laden cough."

So there's no evidence for reducing Covid-19 spread but researchers found it helps reduce exposure. Does that mean that reducing exposure to the virus doesn't reduce the spread of the virus?

Try reading articles like these but with the weasel words removed. For example:
Instead of: "New research suggests that face coverings help reduce the transmission of droplets"
Read it as: "New research demonstrates that face coverings reduce the transmission of droplets"
Or
"masks might offer some personal protection from the virus,"
"masks offer personal protection from the virus,"

Then ask yourself - if that's what they meant...why didn't they write the sentences that way?

 

[OffsetStorefront]

Try reading articles like these but with the weasel words removed. For example:
Instead of: "New research suggests that face coverings help reduce the transmission of droplets"
Read it as: "New research demonstrates that face coverings reduce the transmission of droplets"
Or
"masks might offer some personal protection from the virus,"
"masks offer personal protection from the virus,"

Then ask yourself - if that's what they meant...why didn't they write the sentences that way?

It's bad science to make definite statements like that. In using what you call "weasel words", a study author (or scientifically-aware journalist) is acknowledging there could be flaws or shortcomings in the study that hopefully others will tease out, or a growing body of evidence will back up or refute. Weasel words might be deceptive in the business/sales world, but they're necessary in the science world. Especially in this crisis where urgent decisions have to be made before having the benefit of a body of scientific evidence to back it up. That's why you see guidance change as that body of evidence grows over time. It's not a grand conspiracy, it's adapting to what we learn.

 

[tngcas]

It's bad science to make definite statements like that. In using what you call "weasel words", a study author (or scientifically-aware journalist) is acknowledging there could be flaws or shortcomings in the study that hopefully others will tease out, or a growing body of evidence will back up or refute.

This is exactly why scientist/researchers/doctors shouldn't be relied on to make public policy decisions. They must always make decisions on a CYA basis. They cannot allow themselves to be wrong by making definitive statements or they can be sued and/or lose their status (reputations). This means they have to advocate for the most cautious safe approach that prevents backlash against them and usually only in their specialty. They can't balance other needs (like economics). Viral doctors are cautious about viral issues, mental health doctors are cautious about mental health issues etc.

Public policy is always a balancing of risk vs. rewards. For example: We can reduce the number of car deaths in the USA (the number 1 killer of young adults) by banning cars. Instead we as a society agree that the value of using cars is more important than the value of the people's lives who are killed or permanently injured by vehicles. The risk vs. rewards argument is POLICY (actions taken based on information). WIth Covid-19, when people start talking about sensible policy that balances economics against death counts everyone says they are callous. The suicides, economic ruin, increased domestic violence, childhold social development and the lack of hope for the future are all issues that should matter at least as much as the Covid death counts.

What amount of science allows for someone to make the statement: "Research suggests mask might help slow the spread of covid" vs "Reasearch has proven that masks slow the spread of covid"? When it comes to non-definitive research statements - these are done entirely with bias, with people trying to spin data whatever way they're wanting to spin it. This is why they were able to spend the first three-months of the "pandemic" publishing videos and articles saying masks were not useful while begging ppl to not hoard them and then immediately spin it back to masks are the most important solution anyone has. The same group of people had two different "truths" and they used the truth that was most expedient at the time. The explanation that the science on mask and virus' suddenly changed in 2 months is absurd because while this is a "novel" virus, we as a society have plenty of experience with viruses and masks.

 

[OffsetStorefront]

How well a policy-maker can balance risk vs. reward, as you say, is a measure of their own skill and competence. If a politician is too heavily relying on scientists, as you posit, that's not science's fault - that's a failure in competency in the politician. Turns out it's important to vote for competent politicians - a big problem in the US, obviously.

And on your complaint about how public guidance on COVID has changed since the beginning - while we do have experience with viruses and masks as a society, we don't have experience with pandemics as a society (difference in scale). The few epidemics we've experienced during the course of modern society we mostly ignored or got lucky with. Or didn't learn from.