A really nice story from Kim Tingley about the Skagit Valley chorale outbreak from last year.

Walks through the personal side of the tragedy, how the outbreak provided crucial clues about the airborne spread of COVID. [+ choir song link] HT @jljcolorado
nytimes.com/interactive/20…
2/ “'We proved how you get this thing,' Comstock told me. 'And it’s so damn frustrating to watch the news and see that they’re ignoring it.'”

Link to the important paper by @ShellyMBoulder @jljcolorado @linseymarr @CathNoakes et al.:
onlinelibrary.wiley.com/doi/10.1111/in…
3/ "But the notion that [sitting close, sharing snacks, stacking chairs] caused so many infections, as @jljcolorado characterized it to me, is 'absurd.' He says that that emphasis helped enable the W.H.O. and the C.D.C. to maintain and defend their guidelines."
4/ The facts "made it 'almost impossible to imagine it was anything but aerosol transmission,'" said @Smogdr “'From that standpoint, it was really a watershed study.'”

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More from @HuffmanLabDU

10 Apr
Stronger prevention against the aerosol component of COVID spread is absolutely crucial for public health, especially healthcare. Major pushback against this has cost many lives. Please listen (2 min) to the best reasons why this WHO leader says they are not worth it. 1/
2/ In relation to the comments by Dr. Conly about N95 risks to pregnant women - this is a nice thread by @caruzycki showing major errors in how that study was designed. Authors modified an N95 mask until it was very to breathe through first.
3/ In contrast, there are lots of legitimate & very important reasons to use upgraded masks (N95s, elastomeric respirators) - because they protect lives.
Read 7 tweets
7 Apr
"Is airborne transmission an important and mitigatable aspect of the COVID-19 pandemic?"

Should be a fascinating debate & panel discussion w/ Drs. @kprather88, @DFisman, and John Conly.

This Friday, 4/9 at 2-3 pm ET. Details & free registration below.
events.ucalgary.ca/obrien/#!view/…
A nice thread by @DRTomlinsonEP covering some highlights of the discussion on airborne virus spread today by Drs. @kprather88 @DFisman & Conly.

This slide shows summarizes the importance/why it matters. Click through others for summary o
Another slide from the same thread by @DRTomlinsonEP w/ summary of @kprather88 presentation.

Here summarizing the new & significant evidence over the last year that SARS-CoV-2 is airborne - in relation to evidence WHO suggested should be necessary.
Image
Read 4 tweets
5 Apr
1/ Helpful clarification by #CDC w/ important practical implications to avoid wasting energy & money on excessive surface cleaning:
"each contact with a contaminated surface has less than a 1 in 10,000 chance of causing an infection"

HT @JudahWorldChamp
cdc.gov/coronavirus/20…
2/ Important to note that COVID can potentially spread in individual cases via direct/surface contact, via cannonball-like droplets, or inhalation of aerosols.

The brief clarifies that surfaces are statistically very unlikely to cause many infections; so focus most on the air.
3/ From CDC brief today:
"However, based on available epidemiological data and studies of environmental transmission factors, surface transmission is not the main route by which SARS-CoV-2 spreads, and the risk is considered to be low."
Read 5 tweets
30 Mar
New pre-print: “Respiratory aerosols and droplets in the transmission of infectious diseases”

Happy to contribute to this deeply detailed review paper by Mira Pöhlker et al. & colleagues at the Max Planck Institute for Chemistry.

Link: arxiv.org/abs/2103.01188…

A 🧵summary (1/x)
2/ Preprint review is very detailed: 50 pgs, 20 figures, 7 tables, >360 references.

☑️Reviews literature:
- Respiratory particle size distributions (rPSDs)
- Physical properties
- Emission & shrinkage mechanisms
☑️New multimodal parameterization of rPSDs
☑️Practical perspective
3/ The review ends by showing a parameterized size distribution of respiratory particles & the risks in different parts of a room using #masks, #ventilation, and #filtration. Broad application to SARS-CoV-2 other respiratory viruses.

Link: arxiv.org/abs/2103.01188…
Read 16 tweets
9 Mar
Frequently questions about type of room air filtration & if #ionization is a useful upgrade.

Nearly always, simple filtration is sufficient for most people. Study here shows a bipolar ionizer also *not* useful at reducing PM2.5. Thx @JimRosenthal4. (1/x)
sciencedirect.com/science/articl…
2/ "[experiments] ... suggest that operation of the ionizer unit led to a small increase in loss rates for ultrafine particles (<0.15 μm) and a small decrease in loss rates for larger particles (>0.3 μm), but with negligible net changes in estimated PM2.5 loss rates."
3/ In contrast to relative ineffectiveness of ionization technology to reduce concentration of suspended particles in a room, simple #HEPA filtration does an *excellent* job. See e.g. examples in this 🧵 showing filtration in a school classroom.
Read 7 tweets
7 Mar
1/ More good support that indoor dining is challenging (no masks indoors = risky). Nice article by @RoniNYTimes, w/ comments from knowledgeable folk following a recent CDC #MMWR report.

Amazing this still needs to be news (but it is & still important).
nytimes.com/2021/03/05/hea…
2/ “You have decreases in cases and deaths when you wear masks, and you have increases in cases and deaths when you have in-person restaurant dining,” said #CDC director Dr. Rochelle Walensky
3/ Unfortunately, the Nat'l Restaurant Assoc called the #CDC report “an ill-informed attack on the industry hardest-hit by the pandemic.”

I feel for restaurant owners & workers. I honestly can't imagine the difficulty through the pandemic. But the challenge & risk is legitimate.
Read 5 tweets

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