Thread by @CPita3

For those following this HEPA filter thread – this is a really important acknowledgement. It’s clear from the thread, and this particular tweet, that many Infectious Disease experts still doubt that aerosol transmission is an important/mitigable transmission route for SARS2🧵 1/

https://twitter.com/AntibioticDoc/status/1415100659657940994

While they acknowledge aerosol transmission can occur, they believe it is a rare event occurring in special circumstances, and is therefor not worth the $ to mitigate.
Eg. re HEPAs: "We need to resource by best impact", "Changes need rigorous justification and business case".
2/

See my pinned tweet for a thread summarizing the overwhelming evidence that Aerosol Transmission is an important and mitigable route. At the end, I provided a reference list and posed a question to the ID holdouts - no responses yet.
3/

https://twitter.com/CPita3/status/1381366343900016643?s=20

Once aerosols are acknowledged - physics, models, tests and engineering judgement tell us that HEPA filters and N95 masks will reduce the inhalation of infectious aerosols – this is a well studied field based on physical principles with many experts (eg. Occ Hygienists, IAQ).

4/

The use of HEPAs and N95s is not debatable for other Airborne pathogens (eg. Measles, TB, AGPs) – thus it’s clear the sticking point here is whether Aerosol Transmission of SARS2 is an important transmission route, and whether it's worth the $ of mitigating.

5/

It is implied in this exchange that the *importance of aerosol transmission itself* is still up for debate within the ID community. The implication is ID docs have ceded the public ground, but that they remain unconvinced and unwilling to argue their position on the merits.
6/

This is really problematic. Any ID expert that still doubts Aerosol transmission is a key route – needs to put their cards on the table. The ID field holds the bully pulpit on this issue, influencing PH and IPAC guidelines, and literally holding the keys to the N95 cupboards.
7/

It’s not OK for these experts to sit by silently, watching and waiting for their unreasonably high burden of evidence to be met, all while blocking the deployment of effective Respiratory PPE and engineering controls (N95s, HEPAs).
8/

Even in this thread, the linked paper suggests we need a HEPA filter RCT, before we can recommend them for deployment. That would mean purposely installing a defective HEPA filter in an office or classroom, and then waiting to see if more people got infected. That's absurd.
9/

This is not how engineering controls work – engineers design critical safety systems every day. We use first principles, models, safety factors and redundancies to achieve a safe design. We don’t use RCTs, and we don't ignore lower probability, yet catastrophic, events.
10/

We cannot afford anymore debate or indecisiveness on this topic – we need action. We are at a critical turning point in this Pandemic; opening up with new variants circulating. We urgently need to upgrade or shared indoor spaces to mitigate against aerosol transmission.
11/

This means:

✅#Ventilation
✅#Filtration (including HEPAs)
✅CO2 monitoring (as a proxy for ventilation)

We also need to start consulting the air experts – there are more Canadian experts in IAQ and HVAC than there are Infectious Disease doctors. We need to unleash them.
12/

Engineers are pragmatic problem solvers - operating under difficult technical, schedule and budget constraints. And yet, Safety is #1. It’s engrained into our psyche, it's why we wear the iron ring, as a reminder of our ethical obligations to society.
13/
en.wikipedia.org/wiki/Iron_Ring

I suggest Infectious Disease doctors look into starting a similar tradition to the iron ring, it’s clearly needed.

#ReleaseTheN95s
#UnleashTheEngineers
#UnleashTheOccHygienists

/end

Footnote...

Exhibit A for why this intransigence needs to stop:

https://twitter.com/AHS_media/status/1414962823722045456?s=19

Here's the (now deleted) tweet: