Linsey Marr https://www.threads.net/@linseycmarr @linseymarr Twitter profile

Pinned Tweet

Linsey Marr https://www.threads.net/@linseycmarr

4 years

Let's talk about #airborne transmission of #SARSCOV2 and other viruses. A discussion is needed to improve accuracy and reduce fear associated with the term. /1

310

978

3K

Last Seen Profiles

@Reima3k

@nack555

@FaZe_Rain

@cjliu49

@PMArtois

@SissyDebby

@bbckimghattas

@Nenschka

@cityreport_

@ChrisOtt

@yorditlm

@NikodimHusky

@shuatokki1230

@edrwpalmer

@rc_masajap

@wisernova

@Asifviews

@pepecoineth

@Screamales

@ben_e73

@_verxnica

@herenot_here

@TTamitoz

@mn_elhuseyni

@Air_Kumanui

@Remroum

@DarkSideD_FB

@craig_emily30

@O87XQ

@Jibril_soviet

@RafaBelattini

@TheIHRA

@Tesco_mealdeal1

@maniyu216

@Dabbycat_

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

New study showing that always wearing a good mask (respirator: N95,KN95) in indoor public settings is associated with much lower odds of +Covid test. Real-world evidence confirms basic principles and lab studies. comments from @jljcolorado and me

284

2K

6K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

CDC finally recognizes that the risk of transmission by touching contaminated surfaces is very low. Credit for changing horses midstream. Now everyone should revert to regular cleaning (stop overcleaning) and pay attention to the air instead (ventilation + filtration). No excuses

60

1K

4K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Outrageous! I'm getting on a bus in Canada and was told I need to remove my N95 and put on a loose surgical/medical mask instead. @GovCanHealth needs to fix this. @DFisman

370

640

3K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Don't remove your mask to talk. This is the most important time to wear it! You release a lot more respiratory droplets and aerosols when talking than when just breathing. This school outbreak was caused by unvaxxed teacher who "read aloud unmasked." Had symptoms.🤦‍♀️

Alex Huffman, Ph.D. - @[email protected]

@HuffmanLabDU

3 years

Report on a #Delta outbreak in elementary #school 80% of kids in front 2 rows infected! - Can we pls take school precautions seriously? - Kids <12 yrs unvaxxed & vulnerable - Don't take off your mask (to read aloud)! - Wear a (good) mask **correctly** 👇

93

949

2K

124

1K

3K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

We started studying cloth masks in March. Preprint now at Take-home: Cloth masks are not an N95, but they work reasonably well for aerosols 1-2 microns and larger, which is the size that we think mostly mediates transmission. See thread. /1

121

943

3K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Belgium's plan for ensuring cleaner indoor air is a good model for others: 1) public indoor spaces must display CO2 level 2) risk analysis and action plan 3) targets: level A (CO2 < 900 ppm and clean air provided at 40 m3/h/person) and level B (CO2 < 1200 ppm and 25 m3/h/person)

Maarten De Cock

@mdc_martinus

2 years

Belgium has finally come up with a solid indoor air policy. This ventilation plan could have been done much earlier and it is not perfect, but it will certainly be a step towards more #SafeIndoorAir . Hopefully it may inspire many other countries!

28

809

2K

29

866

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Great visualization of how aerosols move through an airplane. Air changes out every 2-3 minutes and passes through a HEPA filter that removes aerosols. Very important to minimize mask-off time.

How Safe Are You From Covid When You Fly? (Published 2021)

As vaccines become widely available and restrictions are eased, millions of people are flying again, raising questions about just how safe it is now to board a flight.

www.nytimes.com

41

1K

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Travel kit in the age of Covid-19: CO2 sensor as an indicator of ventilation, rapid antigen test, and an extra N95.

220

355

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

If you can see your breath coming through your N95, does that mean it's not working? No, this is water vapor that passed through the N95 as a gas and then condensed into tiny droplets when it hit cold air. I'm in MI. /1

59

572

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Six feet is not enough. Now at 44 primary cases + 17 secondary. The gym did health screening, cleaning, masks before and after class, 50% capacity, and 6' around each bike. NOTHING ABOUT VENTILATION.

One client in one spin studio that followed all the rules triggers a coronavirus outbreak with at...

A spin studio that public health officials say followed all Covid-19 protocols is now reporting 61 positive cases of Covid-19 and up to 100 staff, clients and family members may have been exposed.

www.cnn.com

114

1K

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

This is what we need: automated systems to detect the virus in the air.

China-developed bioaerosol nucleic acid detection system to be used at Beijing Winter Olympics

A China-developed highly efficient bioaerosol nucleic acid detection system is expected to be used at the Beijing 2022 Winter Olympic venues. The system will contribute to smooth and safe Games amid...

www.globaltimes.cn

71

562

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Study confirms that HEPA filters work on SARS-CoV-2, of course. Note that antiviral coating doesn't affect removal from air, since it's a physical process. I sketched expected ratio of concentration at time t to initial concentration as function of t. /1

35

657

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Over 100 years ago, people accepted waterborne diseases as a way of life. Currently, we accept colds and the flu as a way of life. If we treat our air like we treat our drinking water, we can greatly reduce respiratory infections and associated costs.

Prof Cath Noakes #Ventilate 😷 💙

@CathNoakes

3 years

We need to think about ventilation and indoor air as seriously as sanitation and clean water. Our perspective calling for a paradigm shift is out in Science

28

543

1K

27

512

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Nearly tears of joy seeing new paper in medical journal with correct analysis and interpretation of aerosol transmission: See thread for summary of main points. /1

Particle sizes of infectious aerosols: implications for infection control

The global pandemic of COVID-19 has been associated with infections and deaths among health-care workers. This Viewpoint of infectious aerosols is intended to inform appropriate infection control...

www.thelancet.com

65

899

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

I'm not worried about people hanging out at beaches and parks. I am worried that I saw very full parking lots at restaurants last night.

The Associated Press

@AP

3 years

A year after becoming a global epicenter of the pandemic, New York and New Jersey are back atop the list of U.S. states with the highest rates of infection. Case numbers have been inching up nationwide, raising concerns that states are opening too quickly.

88

466

890

25

259

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Here's a 🧵summarizing my testimony on airborne transmission of COVID-19. Full version at /0

35

783

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

The virus doesn't wait until 10 pm to come out. It doesn't stop at 6 feet. It doesn't care that a vaccine is on the way. So wear a mask, avoid crowds, avoid closed spaces, avoid close conversation at all hours.

23

391

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

So...there's an outbreak in a classroom at my kid's school. Here's CO2 in a different building at the school. It rises while kids are in class, drops while they're out at recess, gets uncomfortably high in the afternoon. My recommendation: /1

58

533

2K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

@larmbrust @GovCanHealth @DFisman That's what I did, but this is a ridiculous policy. It's like, take off your seat belt and use this rope instead.

22

72

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Roommates in a hospital became infected, despite >6' spacing with curtains, minimal close contact. Attack rate of 40% is similar to that for household members, so maybe spending lots of time sharing air is more important than close contact for transmission.

Abraar Karan

@AbraarKaran

3 years

Our new study looking at the risk of #SARSCoV2 transmission among patient roommates at @BrighamWomens hospital, now out in CID 12 out of 31 exposed roommates were infected (39%); transmission associated with lower CT values of index cases #covid19

31

249

610

47

605

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

I want to see grandparents at Thanksgiving, but I don't want this to be the last time I see them because they picked up COVID-19 at our cozy gathering of extended family and died from it. We'll wait until they get vaccinated and then celebrate many more Thanksgivings after that.

23

182

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

As mask mandates are lifted, this is an important point to keep in mind: 1 person with N95/KN95/KF94: 90+% protection 1 person with surgical mask: ~50% protection 2 people with surgical mask: ~75% protection And to be fair 2 people with N95/KN95/KF94: 99% protection

David Leonhardt

@DLeonhardt

2 years

Somebody wearing an N95 mask and talking to an unmasked person is at less risk than two people both wearing standard surgical masks, @j_g_allen writes: “Let’s dispense with the notion that masks are only protective if everyone is wearing them."

34

87

400

234

583

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Last day of school for my kids. In-person 4 hr/day since Aug, HVAC⬆️outdoor air, exhaust fans always on, MERV13 filters, portable HEPA air cleaners in all rooms, open windows & doors when possible, masks, about 4-5 ft of distancing, hand hygiene. No known transmission in school🥳

58

270

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

1 year

Accepted version of "Increasing ventilation reduces SARS-CoV-2 airborne transmission in schools: a retrospective cohort study in Italy..." is now at 74+% lower risk of infection in classrooms with mechanical vs. natural ventilation. Seek >10 L/s/person.

24

687

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Stop wasting money on plexiglass! It does not help in this type of setting and may actually be harmful because it impedes proper ventilation. See this outbreak of 20+ people in a sports bar that had distancing and plexiglass. (great story, see whole🧵)

Paula Olsiewski

@polsiewski

3 years

Very disappointing - too much plexiglass, not enough ventilation - thanks for insights @linseymarr New York Is Reopening. Here’s What That Actually Means.

6

49

245

31

391

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Updated today: CDC recognizes that cloth masks act as both source control and personal protection. They protect others AND protect the wearer.

42

541

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

I've now worn the 3M Aura and Vflex enough to offer a verdict. Fit is very personal, depends on the shape of your face. I have a smaller face, low nose bridge, flatter cheeks, and prefer Vflex (small size). It has even pressure all around, stays on chin except when yawning. /1

155

226

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Nice study showing very little in-class transmission, assessed by whole genome sequencing, at Boston University in fall 2021 with vaccine mandate and mask mandate, no distancing.

Eric Topol

@EricTopol

2 years

"Of more than 140,000 in-person class events and a total student population of 33,000 between graduate and undergraduate students, only 9 instances of potential in-class transmission were identified, accounting for 0.0045% of all classroom meetings."

53

235

911

46

421

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Here's the final version of the paper on the outbreak at a restaurant in Jan 2020 by Yuguo Li's team. This and the choir case convinced me, without a doubt, about airborne transmission of COVID-19. Good research takes time.

Kimberly Prather, Ph.D.

@kprather88

3 years

Incredibly well documented study showing the factors contributing to the airborne spread and resulting infections in a restaurant....

13

410

830

19

556

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Lab study showing N95 & KN95 offer best filtration, surgical masks are middling, cloth & bandana by themselves not so good. Doubling up surgical masks or cloth over surgical greatly improves filtration. U-shaped curves because ~300 nm (0.3 μm) is the hardest size to remove.

Marina E Vance, PhD

@marinavance

3 years

Our paper on mask filtration is out! And it's #OpenAccess . Filtration Performance of Layering Masks and Face Coverings and the Reusability of Cotton Masks after Repeated Washing and Drying.

30

247

626

48

665

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

How do we start adapting our buildings for clean air like we did for clean water? It's time for an Indoor Clean Air Act. @kprather88 See /3

A paradigm shift to combat indoor respiratory infection

Building ventilation systems must get much better

www.science.org

32

410

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

We can add a courtroom to the list of venues with well-characterized outbreaks demonstrating airborne transmission. People were distanced and unmasked, broken ventilation system, 3 hours. Cat lawyer by Zoom is safer.

34

555

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

1 year

Hooray! "ASHRAE...today announced its commitment to support the expedited development of a national indoor air quality (IAQ) pathogen mitigation standard. The goal is to finalize the consensus-based, code enforceable standard within six months."

38

401

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Viable SARS-CoV-2 in the air of a hospital room with COVID-19 patients In lay terms: this study confirms, unambiguously in my view, that virus in aerosols (small enough to travel several meters) is infectious. We have suspected this and now have evidence.

Viable SARS-CoV-2 in the air of a hospital room with COVID-19 patients

Background There currently is substantial controversy about the role played by SARS-CoV-2 in aerosols in disease transmission, due in part to detections of viral RNA but failures to isolate viable...

www.medrxiv.org

67

740

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

1 year

Modeling suggests specially designed, personal, portable air cleaner can reduce exposure to infectious respiratory particles by 92-99%.

52

439

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

This is a game changer for Belgium. "If the sensors show CO2 levels of 900-1,200 parts per million, venues are required to take action to improve it, and anything above that level is a safety breach." Not perfect b/c filtration or UV enable higher levels, but good starting point.

Prof. Jose-Luis Jimenez

@jljcolorado

3 years

Belgium imposes ventilation rules for businesses to combat new Covid surge Carbon dioxide monitors must be on public display so customers can see level of fresh air [My comment: An example for every other country to follow]

69

1K

3K

29

440

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Wow, CDC acknowledges that inhalation of droplets/aerosols is thought to be the main way the virus spreads! Now, let's get on with effective interventions: masks, ventilation, distance!

COVID-19 and Your Health

Symptoms, testing, what to do if sick, daily activities, and more.

www.cdc.gov

Kimberly Prather, Ph.D.

@kprather88

4 years

Oh my....was beginning to think I would never see the day. I have a feeling this was helped along by Dr. Fauci. Finally clear guidance--now let's get the message to schools and businesses so they can safely re-open! Congrats to everyone--what a huge team effort this has been!

48

223

718

41

559

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Why is dining indoors at restaurants so risky? No masks because eating and drinking, lots of loud talking to socialize and be heard over the din, long exposure period, probably insufficient ventilation. I'm still supporting local restaurants, but takeout only.

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Community and Close Contact Exposures Associated with COVID-19 ... Those who tested positive for COVID-19 were more than 2x as likely to have reported going to a restaurant in the previous 2 weeks compared to those who got tested and were negative.

26

224

400

37

518

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

55 cases out of 81 people attending exercise classes at a gym, despite 6-ft distancing and some mask use. Ventilation was not assessed.

COVID-19 Outbreak Among Attendees of an Exercise ...

This report describes an investigation of COVID-19 transmission among attendees of indoor high-intensity classes at a Chicago exercise facility

www.cdc.gov

62

711

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

We tested neck gaiters with more conventional methods, and I am pleased to see that they perform similarly to cloth masks and very well if doubled over. Full report at #gaitergate /1

46

479

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Anecdote from my gym: 1 infected coach, 50 exposed athletes, 0 known transmission events. Owner Velvet Minnick implemented strict distancing, ventilation, and hygiene policies. At least 10 feet between athletes and lots of open doors (circled in red) during workouts. Brr, winter.

66

318

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

💯 Omicron gives us another chance to retool messaging: acknowledge Covid-19 is airborne, drop the large droplets, and focus on reducing the amount of virus in the air.

Kimberly Prather, Ph.D.

@kprather88

2 years

@CDCgov & @WHO need to fix messaging and stop treating the transmission modes equally. We must focus on cleaning indoor air via filtration and ventilation. Transmission via fomites and (very few) large falling droplets is much less common. (1/10,000 for fomites per @CDC ).

10

91

308

10

320

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Florence Nightingale was fixated on ventilation for health. Nightingale hospital pavilions "had large windows that faced each other, which allowed a cross breeze to blow between the beds. The windows stayed open no matter the weather." @EThomasEwing

We’re Just Rediscovering a 19th-Century Pandemic Strategy

The first way to fight a new virus would once have been opening the windows.

www.theatlantic.com

32

365

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Our paper examining the origins of the erroneous 5 μm cutoff for aerosols v. droplets and the 6' rule is now published. One of my fave interdisciplinary collaborations yet, involving rhetoric, history, aerosol science, fluid dynamics. /1

How did we get here: what are droplets and aerosols and how far do they go? A historical perspect...

The COVID-19 pandemic has exposed major gaps in our understanding of the transmission of viruses through the air. These gaps slowed recognition of airborne transmission of the disease, contributed to...

royalsocietypublishing.org

20

458

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Plexiglass is useful only for brief, face-to-face transactions, otherwise may be harmful b/c it impedes proper ventilation. Blocks spitballs (HT Holte) but not aerosols carrying virus (imagine cigarette smoke particles). With @CathNoakes @CorsIAQ

Those Anti-Covid Plastic Barriers Probably Don’t Help and May Make Things Worse (Published 2021)

Clear barriers have sprung up at restaurants, nail salons and school classrooms, but most of the time, they do little to stop the spread of the coronavirus.

www.nytimes.com

49

488

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

I fully agree that saying "less than 10 percent" of transmission occurs outdoors is not helpful. It's like saying the high temperature today will be less than 200 F. Here's a better guesstimate: <1%.

A Misleading C.D.C. Number (Published 2021)

We have a special edition of the newsletter on a misleading C.D.C. statistic.

www.nytimes.com

39

227

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Preprint on ventilation intervention in schools in Italy now at . Relative risk of infection⬇️ with⬆️in ventilation: 10-14 L/s per person reduced likelihood of infection 80% compared to natural ventilation only.

Increasing ventilation reduces SARS-CoV-2 airborne transmission in...

Background: While increasing the ventilation rate is an important measure to remove inhalable virus-laden respiratory particles and lower the risk of infection, direct validation in schools with...

arxiv.org

14

464

1K

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Wonderful guidance from @WHO on ventilation. Here are a couple of pages for non-residential settings. All the things we've been talking about: minimum 10 L/s/person, open doors & windows for cross-ventilation, use exhaust fans, filtration.

Dr. Saskia Popescu

@SaskiaPopescu

3 years

The @WHO just issued this great new tool in the overall strategy to reduce COVID-19. 👇🏻 Roadmap to improve and ensure good indoor ventilation in the context of COVID-19

11

151

408

20

503

995

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Best Christmas gift ever: WHO update on 23 Dec finally gets transmission routes right, including the a-word. Inhalation (aerosols/airborne) at short-range and long-range, spray (they call it droplet transmission), maybe touching of contaminated surfaces.

Abraar Karan

@AbraarKaran

2 years

World Health Organization on #Covid19 being transmitted via airborne route H/t @kprather88

13

126

290

42

276

990

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

I forgot my cloth mask today, so it was a good day to try a mask brace for my backup surgical-type mask. A 🧵on making it and my impressions of it. /1

38

284

989

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Phew, we have been working on this review since last summer. It presents a broad overview of the mechanisms of aerosol/airborne transmission of respiratory viruses, merging knowledge acquired from multiple fields over many decades. Thx to Chia Wang and @kprather88 for leading it!

Eric Topol

@EricTopol

3 years

Just published @ScienceMagazine A phenomenal, tour de force review of aerosol transmission of respiratory viruses, from the experts. #COVIDisAirborne w/ @ScienceVisuals

99

3K

6K

20

356

989

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Deep dive by @zeynep from a sociological perspective on what we who have studied airborne transmission for a while, have been observing. /1

Opinion | Why Did It Take So Long to Accept the Facts About Covid? (Published 2021)

The importance of airborne transmission in the pandemic was clear long before the World Health Organization finally began to acknowledge it.

www.nytimes.com

34

406

973

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

SO glad to see @WHO update on transmission! short-range: aerosols containing the virus are inhaled or droplets contact eyes, nose, mouth long-range: poorly ventilated and/or crowded indoor settings, because aerosols remain suspended in the air and travel >1 m

John Johnston

@JOHNJOHNSTONED

3 years

BREAKING🔥🔥🔥 Major breakthrough in the acceptance of the new understanding of respiratory virus transmission of profound significance for the world. @WHO has effectively proclaimed #COVIDisAirborne 14 months into a deadly global pandemic 1/2.

152

2K

3K

30

355

963

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

10 months

Our latest by @isjinpan , Stability of Aerosolized SARS-CoV-2 on Masks and Transfer to Skin, suggests fomite transmission by masks contaminated with aerosolized virus isn't a thing, although it could still be possible with large droplets.

18

343

975

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Here's why I promoted the 3Cs (avoid close Contact; Crowds; Closed, poorly ventilated environments) from the start. "science was used to create an effective strategy and a digestible message. That message — to avoid the three C’s — was actionable..."

Opinion | What Japan Got Right About Covid-19 (Published 2022)

The country embraced the science of the coronavirus early.

www.nytimes.com

22

296

962

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Fauci calls for vaccination, masks, testing, ***improved ventilation*** in schools. Thanks to @kprather88 for her persistence in communicating with him about the importance of ventilation!

New York Times Events

@nytimesevents

3 years

As kids in New York City return to school this week, how do we promote a safer environment in the classroom? Hear what Dr. Anthony Fauci shared with science reporter @apoorva_nyc and other Times journalists at our What We Know About Kids and Covid event.

10

33

96

20

291

944

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

A 🧵on humidity and airborne viruses. Several articles have said that at higher relative humidity (RH), droplets/aerosols retain more water, are larger, and then fall out of the air faster. True, but the effect of RH on biological decay is probably more important. /1

31

344

948

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

This happened to me on a bus in Canada in December. It's scandalous to ask people to take off an N95 and replace it with a surgical mask. Like, take off your seatbelt and use this flimsy rope to tie yourself to your seat instead.

54

179

946

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Thorough article about indoor air quality, and it's not just about virus. A review found "student cognitive performance falls by up to 13% when carbon dioxide concentrations rise from 600 to 1000ppm, and by 24% at 1800ppm." So I can blame the CO2 rather than my teaching?

Nina Notman

@ninanotman

2 years

With thanks to @jljcolorado , @CorsIAQ , @CathNoakes , @NicCarslaw , Stephanie Dancer, @Don_Milton , @Marcel_Loomans , @robertjwest , @LizStokoe & @adsquires

9

214

510

28

322

952

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

1 year

I used to think that "face condom" was an insulting way to refer to a mask, but the Cochrane review made me think differently. Both condoms and masks are physical barriers that work best when worn properly and consistently. If not, the failure rate is troublesome.

104

125

950

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

1 year

How much ventilation is enough? CDC now recommends aiming for 5 air changes per hour (ACH). This and other updates on Ventilation in Buildings at /1

Community, Work, and School

Actions that communities can take to slow the spread of COVID-19.

www.cdc.gov

25

397

949

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Preprint on masks and neck gaiters for source control on manikin by experienced group @NIOSH N95 blocked 99% of aerosols, surgical mask 59%, 3-ply cloth mask 51%, neck gaiter 47% (1 layer) and 60% (2 layer), face shield 2%

58

512

935

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

The problem is not people at the beach or parks; it's people indoors in restaurants, bars, and house parties.

Julia Marcus, PhD, MPH

@JuliaLMarcus

4 years

The media's misinformation campaign continues on the front page of the Sunday @nytimes . What's driving the latest surge in cases? Apparently people enjoying themselves at spacious beaches and parks and drive-in movies.

172

1K

4K

25

277

900

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

What we need in restaurants is more ventilation ( @j_g_allen ), but what we got is QR codes. Love @WBahnfleth 's suggestion of an air cleaner on each table “like a centerpiece arrangement.” Am thinking about getting a battery-powered one to tote around.

Restaurants Learned the Wrong Pandemic Lessons

Are we stuck with QR codes forever?

www.theatlantic.com

58

257

905

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

I spoke with @LaurenPelley about a new preprint comparing survival of Omicron vs. ancestral strain on surfaces. TLDR Omicron is more stable (probably in aerosols too, may contribute to greater transmissibility, my graph of their data👇) /1

28

341

904

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Be the particle and travel through the fibers of the mask. I provided a bunch of feedback for this visualization and look forward to having my students play with it in my Air Resources Engineering class next semester.

Masks Work. Really. We’ll Show You How (Published 2020)

A visual journey through the microscopic world of the coronavirus shows how masks provide an important defense against transmission.

www.nytimes.com

42

282

891

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Grateful to have gotten the vaccine today. The only thing that's changing is that starting in two weeks, I will have sole responsibility for all the grocery shopping until my spouse gets vaccinated, too.

37

35

893

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

“Restaurants were by far the riskiest places, about four times riskier than gyms and coffee shops, followed by hotels” -Jure Leskovec

Limiting Indoor Capacity Can Reduce Coronavirus Infections, Study Shows (Published 2020)

Research using cellphone data in 10 U.S. cities last spring could help influence officials’ decisions on new restrictions as cases resurge around the country.

www.nytimes.com

28

388

877

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

I suspect that inhalation of aerosols is the dominant route of transmission for SARS-CoV-2 and other respiratory viruses, but have been afraid to say so because I have been ignored or ridiculed in the past. /6

81

191

879

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

My rules: mask any time indoors in shared space with people not in my household, outdoors when within ~10' of others and talking for more than a few seconds.

Adam McCarthy

@AdamMcCee

4 years

@linseymarr Can you help expand on “around others”? Does this mean anytime inside and when within 6’ outdoors? Does this change if the indoor space is well ventilated? Is there any safe distance/exposure time ratio indoors?

3

2

22

309

876

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Yes, the "airborne route is likely to be dominant."

Eric Topol

@EricTopol

3 years

Airborne it is. 🦠 The 10 streams of overwhelming evidence @TheLancet by @trishgreenhalgh @kprather88 @Rschooley @zeynep @jljcolorado @dfisman a 5-★ succinct summary

205

7K

13K

23

309

878

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

This is the second or third study I've heard about showing transmission of SARS-CoV-2 by aerosols between vertically stacked apartment units that are connected by vent/exhaust pipes. Definitely not the elevator, or else cases would not line up like this.

Dr. Ali Nouri

@AliNouriPhD

3 years

1/📌Possible #Airborne #SARSCoV2 Transmission through Air Ducts: after a series of infections, all 437 residents of an apt building were tested. 10 infections uncovered, all living on different floors but along two vertical lines with openings through their bathrooms🧵

125

2K

4K

45

369

856

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

"Booster shots" that don't go in your arm: 1⃣ upgrade your mask 2⃣ add a portable HEPA air cleaner to your space 3⃣ open the windows, even just a few inches helps a lot 4⃣ run HVAC with more outdoor air and less recirculated air

26

346

853

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Carefully customize your mask to your nose bridge. You are not a parrot with a sharply angled beak. We know that the nose bridge is a hotspot for leakage.

Frank Costantini

@frankcos

3 years

@linseymarr Kn95s have great filtration, but they come folded in half, and >90% of people wearing them just open the fold, into a V, and don’t reshape it to fit their nose - so lots of leakage.

7

96

176

30

324

857

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Real-life evidence validating the benefits of masks, ventilation, and filtration in reducing COVID-19 transmission. Note: distancing of >6' and use of barriers NOT associated with reduced cases. /1

Eric Topol

@EricTopol

3 years

How to reduce covid cases by ~40% in schools (K-5)? Masks and ventilation improvement New report @CDCMMWR

54

528

1K

21

370

858

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Yes, flu transmission can occur by aerosols, underappreciated. 1) 72% of passengers became ill on plane sitting on runway for a few hours with no ventilation ()... /2

Opinion | What We Know About Covid, the Flu and the Air We Breathe (Published 2021)

We have more power than we thought against the flu and other respiratory viruses.

www.nytimes.com

Don Milton @[email protected]

@Don_Milton

2 years

Influenza is spreading rapidly. People ask, "how is does flu spread?" Look at this video and interview of Dr. Fauci in 2018 by @soledadobrien . Exhaled aerosols contain infectious influenza virus. @rddysum @apoorva_nyc @maggiemfox

5

77

211

14

292

842

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Does My Mask Protect Me if Nobody Else Is Wearing One? At least partially. If you're relying on your mask as the main method of protection (it's crowded, people may not be vaccinated, ventilation is poor), then wear an N95, genuine KN95, or KF94. /1

Does My Mask Protect Me if Nobody Else Is Wearing One?

Masks work best when everyone in the room has one on, but you’ll still benefit from masking up even when those around you aren’t.

www.nytimes.com

21

294

828

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Whoa, this study showed that patients visiting their doctor after a flu patient are more likely to get the flu. Lingering virus in the exam room?

Dr. Julia Raifman

@JuliaRaifman

3 years

@linseymarr Thank you for your work. I was astouded to learn how much better we could do even in hospitals from @HNeprash

11

55

153

59

258

814

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Powerful, accurate new guidance from @CDCgov on how to improve ventilation in your workplace, school, home with options from $0 (open windows & doors, adjust dampers in HVAC for more outdoor air) to HEPA air cleaners to >$1000 for upper room UVGI.

Community, Work, and School

Actions that communities can take to slow the spread of COVID-19.

www.cdc.gov

arkepi

@arkepi2020

3 years

New @CDCgov resource on ventilation, including strategies to improve ventilation & a full FAQ. @ShellyMBoulder @kprather88 @AerosolSociety @linseymarr @NjbBari3 @jljcolorado @ProfCharlesHaas @CorsIAQ

3

88

227

18

393

806

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

On our way to Orlando for some end-of-the-school-year fun at the Wizarding World. Ventilation in the Raleigh-Durham airport is good.

436

70

809

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Good ventilation and filtration prevent the coronavirus and other contaminants from accumulating in the air and thus reduce our exposure. White House spurs efforts to achieve clean, healthy air in buildings. /1

FACT SHEET: Biden Administration Launches Effort to Improve Ventilation and Reduce the Spread of...

Earlier this month, the Biden-Harris Administration released the National COVID-19 Preparedness Plan, a roadmap to move the country forward safely and continue to fight COVID-19 as Americans get back...

www.whitehouse.gov

27

269

806

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Report of the DoD study on airplanes now available. They say it would take 54 hours sitting next to an index case to be infected by aerosols. This assumes breathing and no turning of head. I say risk could be 10x higher with talking, but still low. /1

34

292

800

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

I wrote about applying what we've learned from Covid-19 to the flu. Cleaner air (ventilation & filtration) is a "powerful tool for reducing the risk of Covid-19 transmission, & it should be embraced more thoroughly during this pandemic and to reduce flu"/1

Opinion | What We Know About Covid, the Flu and the Air We Breathe (Published 2021)

We have more power than we thought against the flu and other respiratory viruses.

www.nytimes.com

15

290

791

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

I know very little about monkeypox, but I'm going to weigh in to correct misunderstanding about mechanisms of transmission. Someone claimed, "[monkyepox] virus itself is much larger and heavier and unable to travel as far" because it's DNA not RNA. /1

How Serious Is Monkeypox?

This viral illness is not like Covid, but there is cause for concern. Here’s how experts are thinking about it now.

www.nytimes.com

34

247

782

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

If you're riding in cars with others, here's a very easy thing to do that hugely reduces passengers' exposure to each others' respiratory droplets: open the window a few inches.

Joseph Allen

@j_g_allen

4 years

Source:

7

169

263

14

458

759

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Clarification: Plexiglass barriers between tables in restaurants and in many other applications serve no purpose. They ARE useful for close, face-to-face interactions, like between a cashier and customer at the grocery store, ticket office, bank, to obstruct respiratory plume.

Virginia Tech News

@vtnews

3 years

Do plastic barriers help mitigate COVID-19? No, argues @VTEngineering 's @linseymarr : “Plexiglas barriers serve no purpose and in fact, they can be harmful because they can impede proper ventilation of a room." More from @nbcwashington ⬇️

1

25

46

15

261

755

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

11 months

Link to my @nytopinion piece, free to read for anyone, urging us to embark on a new public health movement to ensure clean air for all. It draws on conversations with many collaborators over the years.

Opinion | What Wildfire Smoke, Gas Stoves and Covid Tell Us About Our Air (Gift Article)

Wildfire smoke underscores the need for better indoor air quality.

www.nytimes.com

35

326

743

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

We'll call it Superspreader Hotel: 3600 ppm in the hallway this morning. Our room was 4300 ppm. This is the worst hotel I've seen by far. Most are around 500-800 in the hall.

234

129

723

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

I tweeted this as a preprint, now accepted. Infectious virus is found in small aerosols (<5 microns) in exhaled breath. More viral RNA is in small aerosols than large. Alpha variant yielded 10-100x more viral RNA in exhaled breath. My note: probably even higher with Delta. /1

Don Milton @[email protected]

@Don_Milton

3 years

Infectious SARS-CoV-2 in Exhaled Aerosols SARS2 evolving toward ⬆️ aerosol generation; loose-fitting 😷=sig. but only modest source control. Until vacc rates very high, layered controls: ventilation & tight-fitting masks and respirators are necessary.

21

265

516

10

327

724

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

“If you’re doing extra hand washing ... then you should also be wearing a good mask in crowded indoor environments,” Marr said. “If you’re bothering to clean the surfaces, then you should be bothering to clean the air.” /1

S_Lakdawala 🏳️‍🌈

@Lakdawala_Lab

2 years

Location matters “Fomite transmission might be negligible at a grocery store, but that doesn’t mean it’s negligible at a day care, where kids are constantly touching things and sneezing on things and sticking things in their mouths.”

8

12

55

11

212

721

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

CDC guidance caught me by surprise, and my initial reaction was supportive, but the more I think about it, I wish they had said, "Let's do this on July 1. If you aren't vaccinated yet, this is your chance to go do it." Give people time to plan.

45

104

718

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Here's how I go out to eat for a romantic lunch date, pandemic style. We picked up takeout at a local restaurant and sat on the curb next to the parking lot, at least 100' from the nearest people.

20

24

710

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

How did I know it was airborne back in Feb? 1) knowledge about transmission of coronaviruses and other respiratory viruses, 2) fast spread, 3) photos of healthcare workers in China and their PPE. Thus, my pinned tweet on March 5 about airborne transmission.

37

181

691

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

Some thoughts for the new year: How do we do public health better in a country with such a strong culture of individualism? /1

124

132

696

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

The 3C's are 1) avoid Close contact, 2) avoid Crowds, and 3) avoid Closed, poorly ventilated spaces.

Abraar Karan

@AbraarKaran

2 years

We need less focus on “another case detected” We are wasting time Free high quality masks Avoid the “3 Cs” from Japan strategy esp if high risk Free rapid tests Get boosted #Omicron #covid19

16

115

543

23

191

697

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Updated on 9 Oct, CDC FAQ says, "It spreads through respiratory droplets or small particles, such as those in aerosols.... These particles can be inhaled...and cause infection. This is thought to be the main way the virus spreads." Best description yet!

21

344

688

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

2 years

"People have been talking about 40 hours -- I think that's fine. Really, it's going to get gross from your face or the straps will get too loose or maybe break before you're going to lose filtration ability,"

33

237

688

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

4 years

Imagine you're sitting in a restaurant at tables this far apart. Someone at the other table is smoking. Are these barriers going to do anything?

Dr. Angela Rasmussen

@angie_rasmussen

4 years

The plexiglass really brings this laughably inadequate infection control theater set together.

224

552

2K

27

212

672

Linsey Marr https://www.threads.net/@linseycmarr

@linseymarr

3 years

Infected after 5 minutes, from 20 feet away: South Korea study shows coronavirus' spread indoors I noted that the interesting pattern of infection suggests droplets/aerosols 20-50 microns played a role. Also... /1

Infected after 5 minutes, from 20 feet away: South Korea study shows coronavirus' spread indoors

A South Korean study raises concerns that six feet of social distance may not be far enough to keep people safe from the coronavirus.

www.latimes.com

20

344

684