Live data from Hacker News

WHO Changes 'Social Distancing' to 'Physical Distancing'

nerdist.com

31–40 of 80 posts

Re: WHO Changes 'Social Distancing' to 'Physical Distancing'

#32

Earlier quoted context omitted.

"vape cloud competition" finds lots of videos that at first blush would indicate that our distance should be much further away. As I understand it - the virus combined with droplets is much denser and doesn't float nearly as much.

Does every breath contain a large number of droplets, or is it mostly limited to sneezing and coughing?

Honestly it's probably both. Each breath will contain some amount of virus baring particles at a relatively low velocity. Each cough and sneeze will release more virus baring particles with a greater distribution of sizes and velocity.

It's key to remember that the 1.5m (or whatever rule) isn't about making you 100% safe, it's about sufficiently reducing risk. For example, if standing at normal (2-3 feet) distance has a 1% chance getting you infected, and at 5-6 feet it has a 0.1% chance of getting you infected, that's a huge win.

Re: WHO Changes 'Social Distancing' to 'Physical Distancing'

#34

Earlier quoted context omitted.

"vape cloud competition" finds lots of videos that at first blush would indicate that our distance should be much further away. As I understand it - the virus combined with droplets is much denser and doesn't float nearly as much.

Does every breath contain a large number of droplets, or is it mostly limited to sneezing and coughing?

Every breath.

Re: WHO Changes 'Social Distancing' to 'Physical Distancing'

#36
post #2

I am hoping we have good science behind the “1.5 metre” distance rule... Does anyone have links to videos that show how breath swirls around, especially in outdoor areas? I guess I could get some pollen and try and model it myself!

Like https://vimeo.com/399120258 ?

Re: WHO Changes 'Social Distancing' to 'Physical Distancing'

#37
post #2

I am hoping we have good science behind the “1.5 metre” distance rule... Does anyone have links to videos that show how breath swirls around, especially in outdoor areas? I guess I could get some pollen and try and model it myself!

This is the only study I know on aerosol transmission of SARS-CoV-2: https://www.biorxiv.org/content/10.1101/2020.03.08.982637v1....

(it doesn't support such simplistic advice of 1.5 meters distance, that advice seems pretty bad and dangerous)

Re: WHO Changes 'Social Distancing' to 'Physical Distancing'

#38
post #2

I am hoping we have good science behind the “1.5 metre” distance rule... Does anyone have links to videos that show how breath swirls around, especially in outdoor areas? I guess I could get some pollen and try and model it myself!

I’ve listened to an interview with a virologist (is that the word?) She said that there have been many studies in how droplets move when people sneeze and cough. These studies have been done with different sized droplets. She said that 1m is probably already enough, so that 1.5m is the recommendation.

Re: WHO Changes 'Social Distancing' to 'Physical Distancing'

#39
post #2

I am hoping we have good science behind the “1.5 metre” distance rule... Does anyone have links to videos that show how breath swirls around, especially in outdoor areas? I guess I could get some pollen and try and model it myself!

Here:

1) Exposure to influenza virus aerosols during routine patient care. https://academic.oup.com/jid/article/207/7/1037/2192312

>HCPs within 1.829 m of patients with influenza could be exposed to infectious doses of influenza virus, primarily in small-particle aerosols.

2) Short-range airborne transmission of expiratory droplets between two people. https://www.ncbi.nlm.nih.gov/pubmed/27287598

>The threshold distance of about 1.5 m distinguishes the two basic transmission processes of droplets and droplet nuclei, that is, short-range modes and the long-range airborne route.

It seems that depending on conditions The goal is to get as small dose viruses at once as possible. Immune system can usually fight off small exposure.

Sometimes even healthy people who inhale huge amount of viruses into their lungs at at once can get very seriously sick because their immune system struggles with the large sudden attack and goes into overdrive.

Re: WHO Changes 'Social Distancing' to 'Physical Distancing'

#40
post #39
post #2

I am hoping we have good science behind the “1.5 metre” distance rule... Does anyone have links to videos that show how breath swirls around, especially in outdoor areas? I guess I could get some pollen and try and model it myself!

Here: 1) Exposure to influenza virus aerosols during routine patient care. https://academic.oup.com/jid/article/207/7/1037/2192312 >HCPs within 1.829 m of patients with influenza could be exposed to infectious doses of influenza virus, primarily in small-particle aerosols. 2) Short-range airborne transmission of expiratory droplets between two people. https://www.ncbi.nlm.nih.gov/pubmed/27287598 >The threshold distan…

1.829m sounds like it was converted from exactly 6 feet.
Post reply on HN