Over two years ago, @WHO and @CDCgov accepted the scientific consensus that COVID is an airborne disease. They have slowly started to shift away from the belief that respiratory viruses are primarily transmitted via sprayborne drops, and now recognize that inhalation… …of aerosols (close- & long-range) is especially significant. Great strides are being made to improve indoor air quality in communities. However, I am hearing that @CDCgov HICPAC is preparing to essentially undo any progress made to protect US healthcare workers and patients…

Very pleased to share @PHABlabumd’s latest work, “Exhaled Breath Aerosol Shedding of Highly Transmissible Versus Prior SARS-CoV-2 Variants” published online, ahead of print in @CIDJournal!

A co-🧵 by @Jianyu16 and @drkristenkc…

academic.oup.com/cid/advance-ar… Curious about viral aerosol shedding patterns of SARS2 over the first 2 years of the COVID pandemic? This 🧵 is for you!

Here, we 1) measured the infectivity and rate of SARS2 shedding into exhaled breath aerosol (EBA) by COVID+ volunteers during the Delta and Omicron waves, and

Get your popcorn ready. Here’s a pre-print of our latest data on SARS-CoV-2 aerosol shedding. 🧵

medrxiv.org/content/10.110… Here, we
1) report rates of SARS2 shedding into exhaled breath aerosol (EBA) by individuals w Delta and Omicron infections,
2) compare viral EBA shedding rates among Omicron subvariants, and
3) describe evolving rate of viral EBA shedding over the first 2 years of the pandemic.

This study is very impressive! They used a rapid deployment modular (RDM) unit in a dormitory parking lot as a controlled chamber for people with covid to spend time. They measure the dispersal of virus under controlled conditions/interventions and via various activities.

https://twitter.com/hoomanparhizkar/status/1443745548574461954

Lots of good data in the paper but this finding stood out to me most: “Data from near field aerosol trials with high expiratory activities suggest that respiratory particles of smaller sizes (0.3 µm -1 µm) best characterize the variance of near field aerosol viral load.” …

Close friend I saw a week ago just tested +ve for covid w mild symptoms. She & her husband had confirmed covid last Dec & are fully vaxxed (~5 months out, Pfizer). Her husband & their baby are both symptomatic (tests pending, baby was sick first). Baby also had covid last Dec 😔 So far I am covid -ve via rapid test. Luckily I had one at home right when I found out. PCR test scheduled for tomorrow AM 🤞🏻 & I bought more rapid tests at CVS (had to call around). I am >7 months out from 2nd Pfizer dose. I am v careful (outdoorsy, otherwise masked) but worried

I do not recommend using @DHLexpress to ship air sampling equipment overseas. After much paperwork, emails, and phone discussions, they finally approved and collected my shipment (late), just to call me later at the last minute to tell me they actually cannot ship my air pumps. Even worse, I already paid the >$6k shipping costs (8 large boxes, mostly personal items) and had to spend another $45 in cab fare to travel to the warehouse to collect the air pumps b/c they couldn't return them to me in time (I am leaving the country).

I note recent queries re the efficacy of portable HEPA filtration in schools. It might help to know that HEPA works wonders in hospital settings. See published studies below. There is no reason to think they should not be used in schools to curb the spread of SARS-CoV-2. "Aerosols rapidly travelled from the patient room into other parts of the ward. Air cleaners were effective in increasing the clearance of aerosols from the air in clinical spaces and reducing their spread to other areas. With 2 small domestic air cleaners in a...

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.

In October 2008, researchers did a study like this in Ontario for seasonal influenza and literally stopped the study because of the 2009 influenza pandemic. Last year, the same PI was granted permission to do this during a far worse respiratory virus pandemic. What is going on?

https://twitter.com/rkhamsi/status/1384924087454154758

Apparently, this is the type of research that is allowed to happen when the importance of infection through inhalation is underemphasized.

In early 2020, we detected airborne SARS-CoV-2 in COVID-19 patient rooms (in the absence of superficial aerosol generating procedures) in a Singapore hospital. We alerted WHO and others immediately and scrambled to get the word out in a preprint on April 9, 2020. Read on...

https://twitter.com/TheLancet/status/1382973273458286593

On April 15, 2020, Singapore (where I live/work) mandated masks for everyone outside their home. Smart move. Given past experience (7 years researching airborne transmission of viruses, now 8), I could see early on that this virus was transmissible through aerosols. So, masks..👍