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I'm pretty shocked staff in supermarket employees aren't required to wear masks in London. But this isn't really true: "One staff member with covid will rapidl

I'm pretty shocked staff in supermarket employees aren't required to wear masks in London. But this isn't really true: "One staff member with covid will rapidly infect a few 1000 people given how busy they are on a Saturday morning. Covid is pretty contagious, but you really need to be around someone for ~15 minutes to have a good chance of infecting them. Superspreading events can occur, but they are fairly rare. I bet supermarkets aren't big transmission vectors.

tzs 6y ago
> Covid is pretty contagious, but you really need to be around someone for ~15 minutes to have a good chance of infecting them ...if you are the only one around them who is infectious.
- deleted 6y ago
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js2 6y ago
Or maybe just five minutes: > If you just want the results: one person (Case B) infected two other people (case A and C) from a distance away of 6.5 meters (~21 feet) and 4.8m (~15 feet). Case B and case A overlapped for just five minutes at quite a distance away. These people were well beyond the current 6 feet / 2 meter guidelines of CDC and much further than the current 3 feet / one meter distance advocated by the WHO. And they still transmitted the virus. https://zeynep.substack.com/p/small-data-big-implications https://zeynep.substack.com/p/small-data-big-implications
EliRivers 6y ago
Covid is pretty contagious, but you really need to be around someone for ~15 minutes to have a good chance of infecting them. Does that mean that someone has to breath in my virus for 15 minutes before there's enough of it inside them to infect them? Or does it mean that if I'm the infected staff member constantly spewing virus near an ever-changing cast of shoppers, I can expect to infect about 4 people an hour, some of whom were near me for only seconds?
- marcosdumay 6y ago
  > Does that mean that someone has to breath in my virus for 15 minutes before there's enough of it inside them to infect them? This one. Kinda. The timing may vary, and it's a risk distribution, so there are tails on the low and high ends.
NickNameNick 6y ago
I don't think that the math works like that. While it might take some time for an infected person in close proximity to push a specific second person across some risk threshold in a 1-on-1 interaction, that's not the scenario we're worried about. We're worried about how many people an infected person might infect during many, many interactions. Even if the probability of infection is low in a single 2 minute interaction, some people in service jobs have thousands of interactions a day. (not all one-on-one).
tonyedgecombe 6y ago
>I bet supermarkets aren't big transmission vectors. I think that is probably true, after all we continued to buy groceries right through the lockdown period and cases remained low.

tzs 6y ago

> Covid is pretty contagious, but you really need to be around someone for ~15 minutes to have a good chance of infecting them ...if you are the only one around them who is infectious.

deleted 6y ago
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js2 6y ago

Or maybe just five minutes: > If you just want the results: one person (Case B) infected two other people (case A and C) from a distance away of 6.5 meters (~21 feet) and 4.8m (~15 feet). Case B and case A overlapped for just five minutes at quite a distance away. These people were well beyond the current 6 feet / 2 meter guidelines of CDC and much further than the current 3 feet / one meter distance advocated by the WHO. And they still transmitted the virus. https://zeynep.substack.com/p/small-data-big-implications https://zeynep.substack.com/p/small-data-big-implications

EliRivers 6y ago

Covid is pretty contagious, but you really need to be around someone for ~15 minutes to have a good chance of infecting them. Does that mean that someone has to breath in my virus for 15 minutes before there's enough of it inside them to infect them? Or does it mean that if I'm the infected staff member constantly spewing virus near an ever-changing cast of shoppers, I can expect to infect about 4 people an hour, some of whom were near me for only seconds?

marcosdumay 6y ago
> Does that mean that someone has to breath in my virus for 15 minutes before there's enough of it inside them to infect them? This one. Kinda. The timing may vary, and it's a risk distribution, so there are tails on the low and high ends.

NickNameNick 6y ago

I don't think that the math works like that. While it might take some time for an infected person in close proximity to push a specific second person across some risk threshold in a 1-on-1 interaction, that's not the scenario we're worried about. We're worried about how many people an infected person might infect during many, many interactions. Even if the probability of infection is low in a single 2 minute interaction, some people in service jobs have thousands of interactions a day. (not all one-on-one).

tonyedgecombe 6y ago

>I bet supermarkets aren't big transmission vectors. I think that is probably true, after all we continued to buy groceries right through the lockdown period and cases remained low.