Wednesday, September 23, 2020

Viral load and outcome in SARS infection: The role of personal protective equipment in the emergency department

 A 2006 study for SARS. 

Although most of the PPE do not confer absolute protection against SARS, it seems that they may lower exposure to the virus, leading to a lower risk of secondary transmission, and be associated with relatively mild disease and a better early outcome

Viral load and outcome in SARS infection: The role of personal protective equipment in the emergency department

25 comments:

NeilW said...

We don't live in an emergency department with high levels of viral load all around us all the time.

Similarly we are not hamsters in cages.

This whole argument is a fallacy of composition and I'm surprised anybody involved in MMT would accept it. It's the same cascade 'sum up the micro to make the macro' argument behind "accelerating inflation".

If masks worked in the wild, then I wouldn't have two children down with viral throat infections two weeks after starting school with full paranoia provisions in place.

Peter Pan said...

When living in fear becomes a way of life...

Matt Franko said...

https://www.hvacwholesaledirect.com/buy/product/Nu-Calgon-4900-20/43555?gclid=EAIaIQobChMIovGRkZP_6wIVieDICh1rgQizEAQYBCABEgIjdPD_BwE

Greg said...

I don’t really understand your criticism Neal

The takeaway is very simple; dose of virus is important (inoculum theory), just like dose of Morphine matters,and wearing masks can lower the dose you inhale. Does it eliminate it? No! N95s do a better job than cloth but even cloth will lower the dose if there are droplets in the air you are breathing.


Also, importantly, saying that there is a relation between dose and sickness does not mean everyone exposed to X amount of virus will have Y level of symptoms. There are varieties of response. Just like not every 70kg person I give 10 mg of Morphine to will stop breathing but I know that I better be watching his respiratory rate because it is quite possible.

This isn’t hard except for the hard headed

Matt Franko said...

Greg ASHRAE says MERV 13 air filters can trap the droplets...

Matt Franko said...

https://www.ashrae.org/technical-resources/filtration-and-disinfection-faq

Matt Franko said...

https://nypost.com/2020/09/22/japanese-firm-develops-first-uv-lamp-that-safely-kills-coronavirus/

NeilW said...

"The takeaway is very simple; "

The takeaway is very simple. It's a belief. Pure Premature Extrapolation and nothing else.

You're not wearing it all the time. So it doesn't work. The network effects dominate because only 0.04% of the population has the virus and there is insufficient density in any situation for it to have any material effect.

As the evidence demonstrates in droves. There is no deflection in infection curves. People in mask locked down areas have bad viral sore throats. Here in the UK Covid infections have gone up since mask wearing started. But amazingly that is ignored.

In Turkey at least they understand it is nothing more than a talisman and have taken to wearing the mask on their elbows rather than pretending it is justified by Scientism.

Greg said...

Dose response curves are how we determine LD 50 of drugs (dose at which 50% of test subjects die from drug) Obviously (hopefully)
there have been no human trials to determine LD 50. It has all been extrapolated from sheep, mice, chimps.
Of course the LD 50 spares half the subjects by definition but it doesn’t take double the LD 50 to kill all in all likelihood. When using a similar concept to determine doses of anesthetic gas to provide surgical anesthesia, called MAC (minimum alveolar concentration to keep 50% of patients from reacting to stimulation) ,it has been shown that going to 1.5 MAC keeps 95% patients from responding
Studies were done on rats years ago with viruses and LD 50s were calculated. There is no reason to believe that humans are any different and that there is a “dose” of virus which would be lethal to almost everyone.
Not knowing what that is or how much is around is a good reason to wear masks. It’s just another barrier that is very simple and hurts almost no one. I know some get their fifi hurt wearing a mask but to date no one has died from a broken fifi

Greg said...

Now, I’m not advocating wearing a mask everywhere all the time but if you are going indoors with a lot of people it’s a really good and effective. Don’t be stupid

Greg said...

Of course just mandating a mask does nothing. If you wear the same one all the time or just cover your mouth you aren’t getting full benefit either Too many people don’t appreciate/understand/care to get full benefit

Matt Franko said...

“ there is a “dose” of virus which would be lethal to almost everyone.”

I believe that and even people who are T cell immune could probably be included...

Matt Franko said...

Why don’t we already have a few thousand dollar tax credit program for installation of airborne pathogen mitigation systems for all HVAC systems?

Greg said...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7393808/#Abs1titled

This is the article discussing masks and inoculum theory

Seems we might be able to eliminate lockdowns and have more outside group activities if masks weren’t such a contentious issue in our culture

There’s evidence you should wear a mask for selfish reasons now, not just to save grandma but to lower your own dose and likely have an a symptomatic infection or low grade infection. Gets to herd immunity with low grade infections instead of higher grade

What’s not to love for a Trumper ; 1) looking out for yourself 2) pursuing herd immunity strategy 3) ending lockdowns. Key is you have to encourage mask use

NeilW said...

You still haven’t addressed the elephant in the room. Why have a school full of mask wearing kids all got a raging sore throat with loads of them off after less than two weeks?

Because the network effects dominate.

Matt Franko said...

They don’t have normal respiration Neil... might be building up bacteria in their upper respiratory... nasal drip.... etc

Matt Franko said...

https://www.maurice.nl/2020/08/05/strong-evidence-of-the-effect-of-ventilation-on-the-spread-of-covid-19-in-nursing-home/

Matt Franko said...
This comment has been removed by the author.
Matt Franko said...

https://www.washingtonexaminer.com/news/catastrophic-unexplained-deaths-at-home-in-uk-nearly-nine-times-more-than-those-from-coronavirus

Peter Pan said...

Wear your silly masks and ignore the fact that your leaders are incompetent. Don't talk about grandma and grandpa dying in the old folks home of covid, because they got infected by the staff.

Greg said...

You do know Neil that it’s entirely possible that whatever virus these schoolchildren have was transmitted from hand to mouth

Matt Franko said...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7332911/

NeilW said...

"You do know Neil that it’s entirely possible that whatever virus these schoolchildren have was transmitted from hand to mouth"

As could SARS2 - otherwise the hand washing and sanitising thing would be off the list and it isn't. This is a secondary school with full mask protocols and sanitiser at the door in every classroom.

Another friend of my daughters is in Wales. Same thing. So it's not just down to Boris, or this school.

Greg said...

I still don’t understand your argument Neil

Is it; Masks dont work cuz my daughters school has a mask policy and many kids still got sore throats and UK has seen a rise in infections concomitant with a mask policy

If so that argument has more holes than Swiss cheese

Masks are simply a barrier. When there are airborne pathogens that barrier provides a level of protection. The level of protection is dependent on many factors such as; is it an N95 or even better and how much pathogen is floating around plus how well the mask fits, to list a few

You really need to stop arguing the science of whether or not barriers work. We know barriers work, but if some don’t use barriers they become.........carriers. So the overall affect of some people wearing barriers can be overcome by more people not. That’s inarguable. A hodgepodge patchwork effort will not be as effective as a coordinated one.......NEWS FLASH!!

Peter Pan said...

Mandatory non-medical (i.e. cloth) masks are the policy in Nova Scotia. They have about as much chance as stopping a virus as they would, with asbestos fibers.

Fortunately, at the time of writing, there is no virus and no asbestos fibers in circulation.