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Dr. Alex Huffman Profile picture
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30 Jan, 6 tweets, 4 min read
Study showing nosocomial (in hospital) transmission of COVID to HCWs despite surgical masks & distancing.

Important b/c:
1) Virus aerosolized w/o AGPs; only possible if airborne
2) Surgical masks insufficient (weak filtration; bad leakage)
via @CPita3 1/x
academic.oup.com/ofid/advance-a…
2/ Conclusions of the study are anecdotal, but they are important b/c they add further direct support to a mountain of diverse evidence suggesting #COVIDisAirborne, though not treated so by #WHO and others.

RT original from @CPita3:
3/ One key, practical take-away: upgrade your #mask quality (#N95, when possible) and always make sure it fits snugly all around to reduce air/virus leakage & transmission risk.
4/ For more support on the importance of focusing on upgraded masks & fit for the general public, more than a dozen recent articles in every major outlet, quoting a variety of experts, have argued this point, e.g. see: docs.google.com/spreadsheets/d…
5/ One example of the recent, widely-reported important call for upgraded masks & fit, w/ a variety of interviewed perspectives (by @skbaer).
buzzfeednews.com/article/skbaer…
6/ Also, a reminder of the nice study by Rothamer et al. documenting the importance & added value of improving mask-fit i.e. by adding an external, inexpensive mask brace:

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Dr. Alex Huffman Profile picture
28 Jan
My heart is heavy today at the loss of Prof. Paul Crutzen, Nobel Laureate and a giant of both science & humanity, truly with no equal.

So many profound contributions: ozone layer chemistry, nuclear winter, #Anthropocene, +

A few quotes & obs. below (1/x)
mpic.de/4677594/trauer…
2/ "He was the first to show how human activities damage the ozone layer. This knowledge ... was the basis for the worldwide ban on ozone-depleting substances – a hitherto unique example of how Nobel Prize-winning basic research can directly lead to a global political decision.”
3/ “Paul Crutzen was also a pioneer of the sciences focusing on the impact of human civilization on the environment, whether through his findings on the destruction of the ozone layer or through his later scientific work on human-made climate change."
nobelprize.org/prizes/chemist…
Read 9 tweets
Dr. Alex Huffman Profile picture
27 Jan
1/ An interesting editorial by Prof. MacIntyre, infectious disease professor at the @KirbyInstitute at @UNSW. Edited by @mariemcinerney.

She postulates on why the COVID pandemic response has been such a "catastrophic failure of many Western democracies".
croakey.org/the-hijacking-…
2/ For reference, Prof. MacIntyre wrote this scientific editorial with @rajah_mich on 'Scientific evidence supports aerosol transmission of SARS-CoV-2"
aricjournal.biomedcentral.com/articles/10.11…
3/ Much focus on importance of a #multidisciplinary approach. A few interesting quotes:

"The evidence is clear that SARS-COV-2 is airborne, yet guidelines in many countries do not yet reflect this, thus hampering the ability to control the spread and endangering health workers."
Read 6 tweets
Dr. Alex Huffman Profile picture
26 Jan
1/ A really good, short read on a very important topic, providing motivation and support for mandated, high-quality #mask-wearing.

By @sri_srikrishna @MonicaGandhi9 @Don_Milton & others = These people you should trust.
hbr.org/2021/01/a-3-st…
2/ COVID19 still very serious & "widespread vaccination is expected to take multiple years globally."

Key arguments from the article above ⬆️ concerning masks.

1. Launch an awareness blitz
2. Communicate about appropriate mask types
3. Prioritize distribution to the vulnerable.
3/ A really important, practical message to emphasize:

Disposable N95s had been in short supply & "have been largely reserved for health care workers. But N95s are now available [widely]."

Should help motivate use of N95s, which have high & standardized filtration efficiency.
Read 5 tweets
Dr. Alex Huffman Profile picture
25 Jan
1/2 @DrLaPook on the importance of quality face coverings (i.e. N95s or even multiple mask layers), esp. as worrying COVID variants rise (via @linseymarr).

But wrt to multiple #mask layers; mask FIT and overall BREATHABILITY also critical, because ...
cbs.com/shows/cbs_even…
2/2 ... If it's hard to breath through a #mask, it is too restrictive/thick. Air (& aerosol) will always escape mask. If air exits via gaps rather than THROUGH layer(s), mask is ineffective!

E.g. watch where/how aerosol escapes this poorly-fitting mask
3/2 (bonus) Since mask fit is so so important (even for N95s), there are various strategies to help improve air flow *through* the mask layers & improve fit. This preprint paper shows improvement in mask filtration efficiency by adding a mask brace/fitter.
Read 4 tweets
Dr. Alex Huffman Profile picture
15 Jan
Important new preprint from Lednicky et al. on #aerosol transmission of COVID

*Aerosol <0.25 - 10 μm collected in car driven by COVID-patient w/ mild symptoms
*Viable virus only detected in airborne particles in size range 0.25 – 0.5 μm

HT @DavidElfstrom
medrxiv.org/content/10.110…
Paper shows: "the potential risk of SARS-CoV-2 transmission by minimally symptomatic persons in the closed space inside of a car (w/ closed windows & air conditioning running), & suggest that a substantial component of that risk is via aerosolized virus."
medrxiv.org/content/10.110…
This 👇 earlier paper by the same Lednicky et al. (published Sept. 2020) showed viable (infectious) SARS-CoV-2 was present in aerosols within the hospital room of COVID-19 patients.

Both add to growing body of evidence of real-world COVID #aerosol risk.
ijidonline.com/article/S1201-…
Read 7 tweets
Dr. Alex Huffman Profile picture
15 Jan
1/ Adding #ventilation helps reduce (but not remove!) aerosols & risk from COVID. One simple measure of ventilation is to keep #CO2 sufficiently low. Simple CO2 sensors can be <$150 and are easy to take with you.

One nice summary of consumer CO2 monitors:
bit.ly/monitorsCO2
2/ The idea is that indoor #CO2 comes primarily from people breathing out; but breathing also produces potentially infectious aerosols. So keeping #CO2 levels <800 ppm (or <600 ppm) means air is likely refreshed rapidly enough to keep aerosol risk low.
3/ There are lots of good resources & articles on improving #ventilation & for using #CO2 monitors for rough checks. This article by @B_resnick from months ago is worth a read as a broad overview on various topics related to air safety wrt COVID/aerosols.
vox.com/science-and-he…
Read 8 tweets

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