Always a great study when tweeted out by Dr. Noakes - let's dive in.
✅2 cases of transmission from bus drivers to passengers up to more than 9 feet/ 3 meters.
✅Genomic confirmation
✅Airflow traced - please see Dr. Noakes original thread for commentary on the method used.
✅2 cases of transmission from bus drivers to passengers up to more than 9 feet/ 3 meters.
✅Genomic confirmation
✅Airflow traced - please see Dr. Noakes original thread for commentary on the method used.
https://twitter.com/CathNoakes/status/1388160910192168960
Limitations:
📌Facemask compliance unsure
📌Fomite possible. Not likely
📌Community transmission possible - but not likely
📌Facemask compliance unsure
📌Fomite possible. Not likely
📌Community transmission possible - but not likely
Two trips and two separate van drivers involved.
Both trips - windows closed, ventilation NOT on recirculate, heaters on medium fan.
First trip - 4 patients on 2-hour trips to and from the hospital on December 2, 2020. Driver tested +positive on December 3, 2020.
Van below.
Both trips - windows closed, ventilation NOT on recirculate, heaters on medium fan.
First trip - 4 patients on 2-hour trips to and from the hospital on December 2, 2020. Driver tested +positive on December 3, 2020.
Van below.
Driver had a high viral burden: 15.9
Driver and all passengers wore cloth facemasks and only interacted during boarding and transportation.
Driver and all passengers wore cloth facemasks and only interacted during boarding and transportation.
Second trip - The second driver transported 3 patients on the same 2-hour trip in the same van on
January 23, 2021, the day his symptoms began.
Van below.
January 23, 2021, the day his symptoms began.
Van below.
Driver viral load was high - 24.
Driver was not in a mask, but the passengers were.
Driver was not in a mask, but the passengers were.
What everyone is most interested in - airflow tracing.
Heater on? Smoke released from the driver seat at headrest height rose and flowed toward the back of the van.
When heater and fans were off, no "microspheres" were recovered from the seats or air.
Next tweet method...
Heater on? Smoke released from the driver seat at headrest height rose and flowed toward the back of the van.
When heater and fans were off, no "microspheres" were recovered from the seats or air.
Next tweet method...
I don't remember seeing this exact technique before in any of the studies I've read. Not saying it's not valid at all. Just haven't seen it.
Contact Tracing Method
Genomic Method.
Our take-aways?
👉 #CoVidIsAirborne.
👉 #BetterMasks are necessary.
👉 If you open diagonal windows, you can create an air curtain. Like in this case, passenger and the window directly behind the driver.
In this case, that last bullet point was not possible due to passenger
👉 #CoVidIsAirborne.
👉 #BetterMasks are necessary.
👉 If you open diagonal windows, you can create an air curtain. Like in this case, passenger and the window directly behind the driver.
In this case, that last bullet point was not possible due to passenger
windows not being able to be opened.
H/T @linseymarr for the air curtain suggestion about 1 million pandemic years ago!
H/T @linseymarr for the air curtain suggestion about 1 million pandemic years ago!
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![Accounting for the differences between indoor and outdoor air ozone concentrations, Weschler [6] has estimated that indoor exposures to ozone are typically 45% to 75% of total exposures. Because breathing rates are lower when people are indoors, the indoor inhalation intake of ozone is typically 25% to 60% of total ozone intake. These estimates may be low for the population most affected by ozone—infants, the elderly, and those with respiratory and cardiovascular disease. Consequently, if there is no threshold concentration for the health effects of ozone, or if the threshold is low, roughl...](https://pbs.twimg.com/media/GfeJAF0WEAAQKXV.jpg)
![We refer to this room as “Room A.” Room A has no window, and is connected via a door to a large, open plan lounge area in the office suite. This Lounge space was used for baseline measurements. The door between Room A and the Lounge was closed during experiments. The air exchange rate in Room A was measured using the CO2 tracer method [33] with portable CO2 sensors (Aranet4) to be 1.3 h-1 (Supplementary Information). Room A and the lounge are carpeted. Room A is equipped with a conference table, a small wooden desk, and chairs. It also has room lighting and a wall-mounted computer monitor. ...](https://pbs.twimg.com/media/GfU28gMXkAAbYMd.jpg)
![The far-UVC average fluence used for the lower-intensity (single lamp) experiments in this study was 0.2 μW cm-2. According to the manufacturer, one lamp is recommended for disinfection of a room the size of Room A. The modelled average fluence and irradiance values are consistent with conditions observed by Eadie et al. in a chamber study to reduce airborne pathogens (S. aureus) by 92% or more [16]. Under these conditions, we did not measure significant changes in ozone level or particulate matter in Room A, despite the relatively low ventilation conditions in the room](https://pbs.twimg.com/media/GfU7WpnXgAEJrmT.jpg)
