On Feb. 29, the U.S. Surgeon General tweeted:

Seriously people- STOP BUYING MASKS! They are NOT effective in preventing general public from catching #Coronavirus, but if healthcare providers can’t get them to care for sick patients, it puts them and our communities at risk!

I, and a lot of others, wondered why masks were not effective for the general public, but imperative for health care providers.

1. This is not a poison, it's a virus. Unless your "experts" can cogently describe how level of exposure effects infection levels - or the body's ability to respond to the virus - then this is garbage.

2. The "experts" are still undecided about how much casual airborne transmission there really is outside of close spaces. I posted here a video from a doctor in NYC's Weill-Cornell hospital who asserted that the primary value of masks is as a tactile cue to keep people from touching their faces.

"or on the beaches during Spring Break."

Please explain how salt and UV make a friendly place for any virus, such that the beach rates with other locations.
Some state, probably yours, is making the news for arresting a paddleboarder for being outside by himself, offshore. He was arrested, forced to spend time in the close company of others, then released to carry the virus home. The offense will be on the order of "failing to do what the State requires."

Do not believe that police will protect you in any case. They will do what is required of them by the State, just like the TSA -- which should be a brilliant warning.

Ben David - true, a virus is not a conventional poison. Poisons do not cause the body to make more poison. The greater the number of virus particles introduced to a body, the further along the multiplication cycle and the faster an immune system can be overwhelmed. This is elementary.

From Crid's 'Dang Ben' series here are a number of good papers on masks and their effectiveness from a variety of years.

https://docs.google.com/document/d/1HLrm0pqBN_5bdyysOeoOBX4pt4oFDBhsC_jpblXpNtQ/edit#

There was a particularly good meta-analysis I got from Crid that covered this and a plausible reason why the CDC has been so opposed to masks. Unfortunately I can't put my hand on it. The argument boiled down to masks are somewhat effective in reducing transmission but are fairly ineffective at reducing reception. Not that they don't have an effect on reception but that the effect is relatively small. Well, due to decades of fighting off medical quackery the CDC and FDA have very hard limits in what they are willing to accept as 'real'. Unfortunately mask effectiveness falls under this line in the sand the two organizations have chosen. So they've been fighting against generalized mask use in the US for decades.

I am always amused by some folks need to use scare quotes around the word experts.

They aren't "experts"... they are experts.

The reason the directives and information being released changes over time is that the experts are constantly learning new things.

This is what it is like to work in an area where things are poorly understood and being actively studied.

You should fully expect to see conflicting reports and tentative conclusions that are later disconfirmed.

Normally this kind of thing doesn't take place in the media, but this is par for the course in the early stages of an investigation.

Current CDC recommendation is to wear masks, so now we adapt to the new information.

I saw that NYT article last week. Since the discussions of “social distancing**” and wearing face masks began, I had wondered if the amount of the virus one was exposed to mattered. It seemed reasonable to me that it did.

The authors write:

Despite the evidence for the importance of viral dose, many of the epidemiological models being used to inform policy during this pandemic ignore it. This is a mistake.

If the evidence is, in fact, very compelling, then I wonder why it’s being ignored. Could it be that there is evidence, but it’s not as compelling as the authors maintain?

** I prefer “physical distancing.” Even prior to the internet and social media, one could be still be social, via the telephone, while not being physical.

“The reason the directives and information being released changes over time is that the experts are constantly learning new things.”

Artemis, I’m sure the experts have been learning new things about this particular Coronavirus but, based on what the authors wrote...

Virus experts know that viral dose affects illness severity. In the lab, mice receiving a low dose of virus clear it and recover, while the same virus at a higher dose kills them. Dose sensitivity has been observed for every common acute viral infection that has been studied in lab animals, including coronaviruses.

...it appears that dose sensitivity is one thing that is well known.

Regarding your comment about scare quotes, I’m sure that Holocaust deniers refer to “historians.”

*I* wish the media would stop being so constantly lazy. That is, they should say "doctors," not "experts." Same goes for any other situation where they have a few seconds to google and come up with the proper nouns instead of a pronoun.

It just might make ignorant, immature people think twice before trying to drag more educated/trained people down to their level.

Ben, there's another problem.

In theory, the CDC could have said "yes, go ahead and wear makeshift masks - to protect OTHER people, that is - but please don't BUY masks, because health workers are in desperate need of anything that's professionally made."

But...as many have pointed out by now, the wearing of makeshift masks would give too many people a false sense of confidence, maybe even to the point of going outdoors or to the store too often. So they could end up catching it and passing it along, all before they have any symptoms.

JD,

It is well understood that viral load is an important feature in contagion.

What has recently been discovered is that unlike the flu which is spread by droplets (which are still small), COVID-19 appears to be spread by aerosolized particles in the breath (which are *much* smaller).

This means that unlike the flu, COVID-19 can be transmitted via a conversation just from the breath even in the absence of a sneeze or cough.

Lenona, the CDC policy on mask is decades old. This isn't a new thing with them. It long predates the current virus. The policy was not put in place due to current supply shortages.

JD, the evidence on viral dose isn't compelling. It is complicated. It is known that small doses have little effect and large doses can have large effect. But where the dividing line sits is pretty much unknown. Some animal testing has been done. But for understandable ethical concerns there is very little data on humans.

Also this isn't about learning new things. You can look at the list of papers on masks I linked. They go back over 20 years.

Ben,

This conversation is in fact about learning new things precisely because it is in response to comments made by Ben David:

"The "experts" are still undecided about how much casual airborne transmission there really is outside of close spaces."

We are in fact still learning about the most important factors in the transmission and spread of COVID-19. Particularly when it comes to asymptomatic transmission (i.e., transmission when the infected person does not sneeze or cough).

This aspect of asymptomatic transmission of particular importance here when the evidence suggests that many infected folks do not display obvious signs of illness.

Artemis, from articles I’ve read recently, it appears that what you mentioned is true: this this virus ca spread via aerosols as well as droplets. However, in an article I just read in The Scientist, it says this:

Virologist Leo Poon of the University of Hong Kong tells Nature that evidence for the airborne transmission of SARS-CoV-2 isn’t yet sufficient, and Nature reports that a study from an outbreak center in Singapore found no evidence of the virus in air samples.

But then there’s this:

Michael Osterholm, an infectious disease epidemiologist at the University of Minnesota, tells Nature that definitive research on the airborne transmission of SARS-CoV-2 may take years, and that we shouldn’t “let perfect be the enemy of convincing.”

JD,

This goes back to what I was saying before:

"You should fully expect to see conflicting reports and tentative conclusions that are later disconfirmed.

Normally this kind of thing doesn't take place in the media, but this is par for the course in the early stages of an investigation."

Normally what happens is this kind of thing is all hashed out in the literature and in conferences where science and medical experts weigh in and continue to study until a general consensus has been established.

What you are observing is how the early stages of research plays out in real time. Everything you hear is going to be tentative and subject to revision.

At this stage of the game things are going to look like a moving target as new data comes in.

From a March 31 article in The NYT, other support for “dosage matters”:

Like influenza, some experts now say, this virus appears to spread both through large droplets and droplets smaller than five micrometers — termed aerosols — containing the virus that infected people might release especially while coughing, but also while merely exhaling. They emphasized that the level of virus in both types of particles is low, so simply jogging or walking by an infected person does not put people at risk.

If you have a passing contact with an infectious person, you would have a very, very low chance of transmission occurring,” said Dr. Benjamin Cowling, an epidemiologist at the University of Hong Kong.

The risk goes up with sustained contact — during face-to-face conversation, for example, or by sharing the same air space for a prolonged time.

Arty, There is new stuff about this specific disease. As for the efficacy of masks, no, there is very little new information there. The issue with asymptomatic but infectious people is not a new one. What we are learning is how prevalent that issue is with this disease.

The CDC's choice to change it's stance on generalized mask usage isn't one based on science but instead based on politics. I am glad they have finally changed their recommendations. But I also recognize why they changed them. It is a pity they didn't do this 50 years ago.

Ben,

I am glad you have decided that none of the research coming out about this specific disease is new... might I recommend that you alert the research community that is devoting substantial resources to researching a topic you have decided is already resolved.

www.ncbi.nlm.nih.gov/pubmed/32171189

www.nejm.org/doi/full/10.1056/nejmc2004973

link.springer.com/article/10.1631/jzus.B2010010

www.preprints.org/manuscript/202002.0283/v1

That is just a VERY small sampling of the research reports that are being published or having pre-prints made available.

Please do yourself a favor and stop asserting something is known here and that none of what we are talking about is new information for this disease when that is exactly what is going on right now.

You still need to work on your reading comprehension Arty.

"There is new stuff about this specific disease." ~Ben

Might want to tone the insults down a bit too.

Ben,

You see insults where none exist.

What you are saying if factually incorrect.

If someone points out that you have said something that is wrong that isn't an insult.

When you say we aren't learning new things about this specific disease you are spreading misinformation.

In fact I see you spreading lots of misinformation regarding COVID-19 on this forum. Please stop.

Just to clarify because I want to avoid confusion I am specifically talking about mask use... we are in fact learning new things about mask use. That decision is NOT primarily political as you are asserting.

You are wrong Arty. Please stop spreading misinformation. And insults too.

Ben,

If someone points out you are mistaken that isn't an insult.

Someone telling you to refrain from spreading misinformation isn't an insult either.

Since you insist that we are learning nothing new with regard to mask use and COVID-19 I will simply point out the following.

Back on March 20th the following article was published in The Lancet:

www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30134-X/fulltext?fbclid=IwAR3jPgQVbLpRJl1ooq4T2Z8gkeSQh0k0NzABKrXSEP5FPyfts-o66LGwxc0

"Despite the consistency in the recommendation that symptomatic individuals and those in health-care settings should use face masks, discrepancies were observed in the general public and community settings."

In other words, the literature isn't yet consistent on the use of masks by the general public and use in community settings.

It isn't a settled issue yet.

The fact you keep speaking about this subject as if it is settled and there is some kind of scientific consensus is incorrect.

We are in fact learning about best practices here and the use of masks in public settings isn't simply a political decision as you keep asserting.

The fact that we are learning that COVID-19 aerosolizes even amongst asymptomatic infected persons changes the calculus as well.

This is an area of active investigation. Please stop acting like this is settled and known.

Arty, you just demonstrated unquestionably your inability to read. Most people cause in such an obvious error might take a step back. Reassess things. Figure out how they could be so obviously wrong. But not you. Instead it is full speed ahead. You may be going in the wrong direction but by god you will get there faster. Lord knows this isn't a one off error. Instead it is normal for you.

So I say again, please stop spreading misinformation and work on your insulting behavior too.

Ben,

This is what you said regarding masks verbatim:

"Also this isn't about learning new things. You can look at the list of papers on masks I linked."

The reference I provided to you has 8 separate references from March of this year regarding different mask related policies based on different learnings on how to handle COVID-19.

I didn't imagine that you said this isn't about learning new things with regard to mask use during this pandemic... it is what you explicitly said.

If you would like to correct or amend your previous statement you are welcome to do so, but I am addressing an actual statement you made.