[badfrog]

> air is recirculated

That shouldn't actually matter. As far as we know, coronavirus is not airborne. From the WHO:

> According to the currently available evidence, transmission through smaller droplet nuclei (airborne transmission) that propagate through air at distances longer than 1 meter is limited to aerosol generating procedures during clinical care of COVID-19 patients.

> as the droplets are too heavy to be airborne, they land on objects and surfaces surrounding the person.

https://www.who.int/docs/default-source/coronaviruse/situati...

[mannykannot]

I am willing to be pursuaded, but the quote you have given us contains the caveat "at distances longer than 1 meter", while, in the scenario being discussed here, distances of less than one meter are relevant.

The quote also presents its case as 'absence of evidence' rather than 'evidence of absence'. In the early (and not-so-early) pronouncements about HIV/AIDS, there were a number of significantly harmful false claims (notably, about it not being transmissible heterosexually) being made by health organizations as a result of confusing the former for the latter.

Also, let's take a look at the text surrounding these quotes [my emphasis]:

"In all other contexts [i.e. other than the experimental setup being discussed], available evidence indicates that COVID-19 virus is transmitted during close contact through respiratory droplets (such as coughing) and by fomites.

...

"As such, WHO continues to recommend that everyone performs hand hygiene frequently, follows respiratory etiquette recommendations and regularly clean and disinfect surfaces. WHO also continues to recommend the importance of maintaining physical distances and avoiding people with fever or respiratory symptoms. These preventive measures will limit viral transmission."

The quotes have been taken from a passage discussing the significance of a specific experiment.

[brianchu]

The WHO is no longer a trustworthy source. But this is still (mostly) correct, and it's not that hard to dive into the studies directly instead of appealing to authorities. All indications are that it is possible for SARS-Cov-2 to be airborne but it is rare.

The main study from Wuhan that people cite for airborne SARS-Cov-2 only found high levels of airborne SARS-Cov-2 in poorly ventilated areas of a hospital setting (where certain medical procedures like intubation are known to generate aerosols): https://www.nature.com/articles/s41586-020-2271-3. Well-ventilated areas had very low levels. A separate study in Singapore found no airborne samples in a hospital setting (https://jamanetwork.com/journals/jama/fullarticle/2762692). Documented spreading events are consistent with the disease not being aerosolized (one example: https://twitter.com/zeynep/status/1251556084424347649).

[dannyw]

The WHO is the same organisation that has been telling people that face masks are not useful [1], repeating claims like no H2H transmission while ignoring warnings from Taiwan, discouraging travel restrictions and bans as late as Feb 29th citing trade and economic impacts (!!!) [2], and even fearmongering tweets like people can be infected with COVID19 twice (that they shortly retracted) [3]; so it's really hard to take this body as credible.

[1]: https://www.sciencemag.org/news/2020/03/not-wearing-masks-pr...

[2]: https://www.who.int/news-room/articles-detail/updated-who-re...

[3]: https://reason.com/2020/04/26/world-health-organization-twee...

[sneak]

The fact that the WHO is sometimes wrong does not mean that they are always wrong. It also does not mean that any WHO-sourced fact should immediately spawn this reply. In general, the WHO gets more right than they get wrong.

I’m critical of the WHO too but I don’t think it’s productive to make this kind of left turn in this kind of thread.

Do you have any data that suggests the specific WHO-sourced claim in this thread and on this topic is not accurate?

Otherwise it’s just ad hominem, which is noise.

Let’s put it another way: There is no currently available evidence of airborne spread of ncov. That’s a fact regardless of whether the WHO says it or not.

Please remember to keep in mind that the data and the messenger are separate.

[dannyw]

Absolutely. While this article does not come from a well known outlet, all of the evidence presented comes from peer-reviewed studies, universities, and organisations like the International Laboratory for Air Quality and Health:

> The frustration lies with the fact that WHO is clinging to a 90-year-old medical dogma. The droplet dogma, articulated by William Wells in 1930 for tuberculosis, holds that contagion is largely limited to the distance covered by droplets that are larger than five to 10 microns in size.

> Several types of studies now challenge that view.

> A 2003 paper in The New England Journal of Medicine documented a flight in which one SARS case led to 16 possible infections – eight of whom were sitting within three rows of the symptomatic patient. Another study the same year suggested SARS transmission through an air shaft in a housing complex in Hong Kong.

https://australiascience.tv/is-covid-19-airborne-dont-know-b...

Another scientific article directly on the airbourneness of COVID19: https://www.sciencedirect.com/science/article/pii/S016041202...

As an anecdotal evidence, I'd like to point to the Diamond Princess cruise ship. Infections continued to grow on the lockdowned cruise ship, where meals were individually delivered and people weren't allowed out of their rooms except for brief exercise with no contact.

How could so many people have been infected if COVID19 is not airbourne? Air recirculation is a prime suspect.

My view is that it is not reasonable to adopt a position that COVID19 is not airborne; and the position taken by the WHO should be discounted (not that we should always take the opposite of WHO; but that should NOT be the end of it given all the failures they have had to date).

[new2628]

Absence of evidence is different from evidence of absence.

[jpallen]

'if X is true then I expect to see evidence of X' is generally a reasonable assumption/prior. So not seeing evidence of X is evidence that X is false. It's not proof, but absence of evidence generally is evidence of absence, unless you have a specific reason to believe it's not.

[new2628]

The specific reason is the asymmetry in being wrong in one direction vs the other. If we thought a virus does not spread in a certain way and we are wrong, we may die. If we thought the virus does spread in a certain way and we are wrong, we may unnecessarily wear a mask.

[lsiebert]

So basically they said the same thing as the CDC and the NHS? This seems to be something I hear a lot of in the anglosphere, ignoring that the WHO is arguably why things aren't way worse, especially in countries that don't have particularly robust epidemiological systems.

This is a completely new virus that just crossed over from animals at the end of last year, and best practices evolved as everyone learned more, and recommendations evolved based on what they felt they could convince people to do at any specific point in time.

Oh, and you may find this educational. It's about a pandemic preparedness exercise in october of last year https://www.forbes.com/sites/judystone/2019/12/12/how-prepar...