What happens when your "high standard of proof" is so high that it cannot be reached in a reasonable amount of time before implementing common sense infection prevention strategies for a pandemic respiratory virus?

Global demise.

That's what. https://twitter.com/fascinatorfun/status/1386823620547293188

The very thing these authors are proposing, is the very thing that prevented the acknowledgment and control of aerosol transmission of SARS-CoV-2.

This "hierarchy" excludes epidemiology, occupational health, engineering, and aerosol science.

It is biased and needs revised.

These "levels" (sort of) make sense for "proving" causality in the basic sciences, but they should NOT be required before taking action.

They are proposing to do what they have already done, and look where that got us!

Imagine if we subjected chemicals to this standard while waiting for stringent "proof" of causality of injury/toxicity/disease...

"I inhaled a toxic chemical and now my lungs are damaged"

Sorry, we actually can't prove whether you inhaled it or touched your face. We think you touched your face, so best to just wear gloves and wash your hands until we learn more. We do not acknowledge the concept of vapors.

"I wore gloves while handling this toxic chemical, removed them and washed my hands after, and now my lungs are damaged"

Hmm. You must have splashed it into your face then. Try wearing safety goggles and a surgical mask to block the splashes. Don't forget to wash your hands!

"I wore gloves, safety goggles, and a surgical mask while handling this toxic chemical, removed them in proper order and washed my hands after, and now my lungs are damaged"

Hmm. Did you make sure to thoroughly clean the surfaces around you?

"Yes, of course!"

Keep doing that.

"I wore gloves, safety goggles, and a surgical mask while handling this toxic chemical, cleaned the surfaces around me, removed my PPE in proper order, washed my hands after, and now my lungs are damaged"

Wash your hands more thoroughly. The evidence doesn't prove inhalation.

"I wore gloves, safety goggles, and a surgical mask while handling this toxic chemical, cleaned the surfaces around me, removed my PPE in proper order, washed my hands TWICE after, and now my lungs are damaged"

This pathway is likely insignificant. Wash your hands.

"My coworkers wore gloves, safety goggles, and a surgical mask while handling this toxic chemical, cleaned the surfaces around them, removed their PPE in proper order, washed their hands twice after, and now their lungs are damaged"

Again, this is rare. Were the vapors <5μm?

"I wore gloves and safety goggles while handling this toxic chemical UNDER A FUME HOOD, cleaned the surfaces around me, removed PPE in proper order, washed my hands twice after, and my lungs are NOT damaged"

See how effective hand washing is!? The fume hood is unnecessary.

"My friends always use a fume hood to handle this toxic chemical and they've never experienced lung damage after"

We need an RCT of fume hoods. Harms include acne. So far the data are low quality & do not prove that inhaling this chemical causes problems. Wear a surgical mask.

Anyways, you get the point.

Perhaps the authors' lab safety and ethics trainings have expired & they need a refresher on the actual 'hierarchy of controls' pyramid.

They should ask an engineer or occupational health expert.

Wait, I forgot they don't acknowledge those either.

I read the preprint again and I still can't believe an advisor to WHO is proposing a hierarchical framework that is so out of touch with reality and global health. It assumes that every country in the world has the laboratory capacity to do these experiments. In an emergency.

News flash! Many countries do not have the lab capacity to do this at all. And among the countries that do have the capacity, we still have not reached "evidence level 4" for a virus that is clearly airborne.

And whom are they proposing carry out these experiments?

Unbeknownst to these authors, there are labs out there (including mine) that have voluntarily spent countless hours & discretionary funding to do research on this topic to help the authorities save people. We disseminate data as quickly as we can and what are we compensated with?

Worthless preprints written by folks stuck on their high horse, categorizing our work as "low quality" in an effort to shift responsibility onto scientists while the authorities fail to acknowledge the science for what it is and act appropriately.

It is as if the scientific evidence is more important to them than saving lives.

It is as if the purpose of this proposed hierarchy is to save authorities from being held accountable for their negligence during a public health crisis.