This is why research & #scicomm now about virus transmission is so critical
"We’re going to have to be in a world that is more thoughtful about protecting ourselves from respiratory infection than we have ever had to be before.” Dr. Bloom, @HarvardChanSPH pri.org/file/2021-02-0…
(Starting at 2:31): “This is a global infection. A mutant or variant anywhere is a threat everywhere. And so we can’t be complacent and say because hopefully we start to do well by summertime in the US we will not be invaded by a new variant. So we really have to ..."
".. continue public health measures: wearing masks, reducing opportunities for spread, and being very careful, because even with vaccines, they’re not perfect, no vaccine has ever been perfect. ..."
"..And we’re going to have to be in a world that is more thoughtful about protecting ourselves from respiratory infection than we have ever had to do before.”
"The best way to prevent the emergence of mutants is to reduce the amount of circulating viruses that hang around and can make mutants. So the lower the number of viruses in the community, the lower the number of viruses in any individual through..."
".. through facemasks, through distancing, through avoiding crowded places, through washing of hands, the lower that number is, the lower the probability a mutant will emerge. That’s the simplest of all facts. ..." (Dr. Bloom)
2/ "In times when classes were conducted with windows and door closed, the aerosol concentration was reduced by more than 90% within less than 30 min. when running the purifiers (air exchange rate 5.5 ACH). The reduction was homogeneous throughout the room ..."
[note log y-scale]
3/ Figure 3: Highly reproducible reduction in aerosol particle concentration [uCPC] in a closed classroom without air purifiers (blue line) and with 3 or 4 air purifiers operating at speed 3 or 4 (max).
1/ You've surely seen constant recent messaging & articles imploring you to improve quality of both #mask fit & filtration, in part b/c of worrying COVID variants.
Good news that the #CDC is catching up w/ those messaging efforts w/ updated guidance today.
3/ One good example summarizing the new #CDC guidance changes on masks, w/ helpful infographics, interviews, and short video w/ CDC chief Dr. Walensky.
1/ In context of extra precautions against new COVID variants, some new questions pop up about #masks.
Article by @cwarzel@zeynep asks/answers some good questions to start. Other thoughts in a 🧵, e.g. N95s, fit (Tw7+ ⬇️), when to replace (Tw25 ⬇️), etc. nytimes.com/2021/01/29/opi…
2/ Countless recent articles w/ interviews from relevant experts imploring people to still take mask-wearing & overall airborne COVID health seriously.
1/ Public admission by @mvankerkhove of #WHO that COVID transmission "goes through the air" is a *huge* turn-around from strong, incorrect statements to the contrary.
Strikes me as significant, even if subtle & played off as "we knew all along."
2/ Earlier messages #WHO put out were blatantly wrong & dangerous ⬇️.
Many scientists globally have been working tirelessly to pressure @WHO to retract dangerously misleading statements like this & adequately educate that #COVIDisAirborne.
3/ Again, messaging efforts by WHO are critical b/c of their exposure & reach. By openly saying COVID isn't in the air & having press conferences w/o masks, have been undermining efforts to #MaskUp & prevent spread.
2/ Study used the #WellsRiley model to estimate COVID risk from respiratory aerosols in a variety of scenarios, using particle size distribution data from previous studies.
Quanta: Statistical measure of avg infection probability; bigger value = easier to infect [~1 - e^-quanta]
3/ Bazant & Bush study supports broad consensus of observation & preventative steps:
✅No single action sufficient for COVID prevention
✅Steps compound reduction in risk, but never to zero
✅All important: distance, masks, reduced time, incr. ventilation medrxiv.org/content/10.110…
"Excessive attention on making surfaces pristine takes up limited time & resources that would be better spent on ventilation or the decontamination of the air that people breathe": @linseymarr
2/ A few other key quotes/reminders:
“It’s become clear that transmission by inhalation of aerosols — the microscopic droplets — is an important if not dominant mode of transmission,” says Prof. @linseymarr , who studies airborne disease transmission.
3/ “You have to make up some really convoluted scenarios in order to explain superspreading events w/ contam. surfaces”
“If we’ve already paid attention to the air & we have some extra time resources, then yes, wiping down those high-touch surfaces could be helpful”: @linseymarr