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Lazarus Long Profile picture
@LazarusLong13
Sep 6, 2025 • 8 tweets • 4 min read • Read on X
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Remember THAT scene from Outbreak with Dustin Hoffman - "It's Airborne." ?

SARS-COV-2 is airborne via HVAC. Just like TB is - but it is way more contagious.

Still no panic, right? We know how to be safe.

Motel 6, or AirBNB - no shared HVAC, is best.

But HOW do we know?

🧵
A recent study in South Africa used Syrian Hamsters to duplicate the study that finally convinced everyone that TB was airborne.

The TB study is interesting because the military vets in VA hospitals were getting infected disproportionately.

So, they used HVAC ducting to In 1956, tuberculosis was a major global killer, and it disproportionately affected military veterans hospitalized in the Veterans Administration hospital system. Then, as now with COVID-19, epidemiologists held that tuberculosis and other respiratory diseases were spread by large infected droplets through person-to-person contact or contaminated surfaces. But Richard L. Riley, an expert on lung physiology at the then Johns Hopkins School of Hygiene and Public Health, and his mentor, William F. Wells, had identified another possible mode of transmission.
connect a 6 room TB ward to 150 guinea pigs.

Of those 150, only 3 PER MONTH got infected.

Illustrating that TRANSMISSIBILITY is just a CLUE to if something is airborne.

Dr. Riley went on to patent UVC tech, and develop the Wells-Riley equation which is so important in airborne Atop the Baltimore VA Hospital, they constructed an air-tight closed ventilation system that connected a six-room tuberculosis ward to an exposure chamber with 150 guinea pigs. (Among rodent animal models, only guinea pigs could cough and sneeze, making them ideal for studying how respiratory diseases spread.) The guinea pigs were exposed to the infected air over a four-year period. A second group of 150 guinea pigs acted as controls: their air ducts were irradiated with UV-C lamps to kill TB bacilli.
In the test group, an average of three guinea pigs per month contracted TB, while no controls were infected. The experiment not only proved the airborne disease transmission of tuberculosis for the first time, but also quantified how many TB infections could be expected to result from exposure to a given number of patients over a defined interval.
The insights from the Baltimore VA Hospital studies were later used to develop the Wells-Riley equation, which quantifies infection risk and informs strategies to ensure staff and patient safety in contagious clinical environments. The model can also calculate the risks of transmission for airborne infections on planes and trains, in prisons, and in other public and institutional spaces. As chair of the Department of Environmental Medicine from 1960 to 1977, Riley warned that the danger of infection from airborne diseases was increasing as people spent more time indoors and air conditionin...
So, in South Africa they have a facility designed to study airborne very similar to the TB set up.

7 C0V1D patients' breath was routed to 216 Syrian hamsters.

58% of the hamsters got COVID antibodies in 21 days.

3 TB guinea pigs versus 100+ Syrian hamsters. Impressive! 1.Floorplan schematic of the South African Airborne Infections Research clinical facility. The facility consists of a 6-bed inpatient ward, toilet facilities, and day room, all serviced by an airtight ventilation system and manifolded to 2 animal rooms housing the sentinel animals. All exhaust from the clinical area is shunted so only a portion (approximately 10% of the total flow) enters the individually ventilated animal caging units, with the remaining 90% flow bypassing the caging but passing through the animal rooms. High-efficiency particulate air–filtered flow is supplied to the pati...
"The simplest interpretation of our results is that human-generated aerosols seroconverted 58% of exposed hamsters after traveling the 7-10 meter distance through the ventilation system of the AIR facility," the authors wrote. " The simplest interpretation of our results is that human-generated aerosols seroconverted 58% of exposed hamsters after traveling the 7-10 meter distance through the ventilation system of the AIR facility," the authors wrote. "This data indicates that exposure to exhaust air from the clinical ward containing individuals actively infectious for SARS-CoV-2 can result in transmission to susceptible animals."
About this study, Dr. Osterholm:

"This one was a classic study design, and we don't often say that in science," said Osterholm. "This study should put the nail in the coffin that SARS-CoV-2 is not transmitted by airborne routes."
CIDRAP
cidrap.umn.edu/covid-19/using…

Study
academic.oup.com/ofid/article/1…

TB article
publichealth.jhu.edu/2020/the-exper…

TB study
sci.bban.top/pdf/10.1093/ox…

And yes, COVID is airborne.
One more thing....these patients were NOT prime infectious agents.

That happens BEFORE symptoms show up.

This thread is starting to go viral, so I am now anticipating some minimizers will attempt to criticize prior to reading the study.

Read the study. I have, and am ready.

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More from @LazarusLong13

Lazarus Long Profile picture
May 22
The "epidemiology" of Ebola tells us that it's not airborne. You've heard this over and over.

What drives it? The questions on the contact tracing form.

Quick 🧵. Image
COVID - the WHO and CDC said it wasn't airborne via aerosols, right?

The CDC said it was spread person to person via close contact - within about 6 feet.



And you remember it took FOREVER to get changed.

The contact tracing form was web.archive.org/web/2020032817…Image
Image
arranged around close contact. These are the questions driving the stats of how many and how are infected.



So, the CDC will only hear back what it's asking. This was the epidemiology of COVID - until it wasn't. web.archive.org/web/2020052514…Image
Read 16 tweets
Lazarus Long Profile picture
May 20
Speaking of silly, can we agree that the WHO has Ebola experts?

Let's talk about PPE, and a bias towards "less PPE is better." Image
The WHO EBOLA IPC guidance:


Foreshadow on PPE

"...due to the desirability of an off-
the-face design, and not for protection from aerosols, respirators may be used instead of medical masks"who.int/publications/i…
If you can stay 3 feet away while screening? No medical mask needed. Image
Image
Read 12 tweets
Lazarus Long Profile picture
May 10
Great article by @EmilyJoshu here.

Emily, there's another article in this that's even more shocking.

The aerosols from milking have long been discussed by many of us on X.

People like myself, @sri_srikrishna, @AbraarKaran have long advocated for comfortable aerosol
protective gear like PAPRs. But, have been ignored by the USDA who, of course, thought it was only contaminated milking gear like the claw.

But there is one more source of aerosols besides cow breath.

The wastewater. When you spray anything you generate huge amounts of Image
aerosols. And that farm wastewater, filled with milk dumped from being full of H5N1, gets reclaimed and reused.

Those milk and wastewater lagoons are on most dairy farms (my grandfather owned a dairy farm).

And there's something you should know.

Image
Read 15 tweets
Lazarus Long Profile picture
May 7
Humanity's hubris vs the precautionary principle.

The virus, ANDV, will do what it will do. Pandemic? History tells us "NO." But history is in the past.

Let me show you what the studies tell us - and why I am livid that the WHO is insisting that surgical masks are ok.

🧵
Incubation time, or how long until symptoms show up?

The high risk time frame is 14–32 days. Not to put too fine a point on that, but that can mean a full month later

pmc.ncbi.nlm.nih.gov/articles/PMC32…

There have been some out to 8 weeks, but let's ignore those

gov.uk/guidance/andes… Image
Clinical features The most important complication of ANDV infection is HCPS, which is associated with a high mortality rate. Milder illness without significant cardio-respiratory compromise may also be seen. Illness usually develops 2 to 4 weeks following exposure, but incubation periods as early as 4 days and up to 8 weeks have been described.
But, what receptor does the ANDV attach to?

PCDH1 (protocadherin-1) is primarily expressed in the airway epithelium of the respiratory system, especially in the bronchial and nasal epithelial cells, and in pulmonary endothelial cells.

So, that means in the URT and the LRT.
Read 41 tweets
Lazarus Long Profile picture
May 6
@mvankerkhove - a follow-up question on today's press conference.

In this bit, you were thanked for being very clear.

But, you said that the medical personnel taking care of those sick would be wearing PPE.

N95s are not PPE. They are Respiratory Protective Equipment. /1
Surgical masks are PPE.

So, is the WHO advising them to wear surgical masks or N95s/FFP2/KF94/KN95 (respirators)?

Second followup, @mvankerkhove, you referred to "really close contacts"

Close contacts are defined by the WHO as within 3 feet.
Cases 1 & 2 were close contacts.

How did the other cases get it? I realize you cannot possibly have an answer...but you are labeling this as "really close contact" for those cases - as well.

Staterooms are typical 2 person rooms.

It doesn't add up. Image
Image
Read 12 tweets
Lazarus Long Profile picture
Mar 26
I've become a bit of a Dental Nerd after just getting savaged by avoiding the dentist due to COVID.

But, now, I have a Dental Nasal PAPR, know all about Stephan's Curve, use a waterpik, Oral-B iO Series 10, chew 8 pieces of xylitol gum - and the dentist just said that.....
He has never seen anyone reverse course so perfectly before.

"Immaculate."

And bonus...I ran into a fellow masker in his lobby!!

She had never heard of Readimask, so I was super happy to share the Good Word with her.

Sharing the Good Word - not COVID!
Good point.

Read 4 tweets

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