# Can someone do the maths for me?



## Odea (22 May 2020)

Based on the number of new cases per day in Ireland, say 70. What are the mathematical chances of me picking up Covid-19 if walking on a beach that had 3000 people on it?

What are the mathematical chances of me getting it, if I was in a supermarket with 100 other people?

I am sure the chances are miniscule. So, is it not the case that we are all worried about meeting an asymptomatic person in our travels.

What are the statistical chances of that in the above two scenarios?


----------



## Purple (22 May 2020)

If 60 of the new cases are not community based (i.e. they are in Care Homes and Meat Factories etc.) then you have one chance in 500,000. Given that less than 1% of infections take place outdoors then your chance of getting it on the beach is probably closer to 1 in 50 million. I'm sure my figures are wrong as I'm not taking everything into account but I bet I'm not that wrong. If you do get it and you are not in an at risk group you have less than a 1% chance of dying from it.  
Basically I'd be happy to walk on a beach without fearing for my life.

Shopping, now that's another matter; you are taking your life in your hands there.


----------



## elacsaplau (22 May 2020)

That's ridiculous, Purple!

Basically, you are saying that what you put into the shopping trolley (your eating habits) is more likely to impact on your longevity than whether you put your hands on the trolley or not....


----------



## Purple (22 May 2020)

elacsaplau said:


> That's ridiculous, Purple!
> 
> Basically, you are saying that what you put into the shopping trolley (your eating habits) is more likely to impact on your longevity than whether you put your hands on the trolley or not....


Ohhh, I'll use that. Thanks!


----------



## Leo (22 May 2020)

elacsaplau said:


> Basically, you are saying that what you put into the shopping trolley (your eating habits) is more likely to impact on your longevity than whether you put your hands on the trolley or not....



That's actually an interesting point. To date this year we've had just over 1,300 premature COVID-19 related deaths, but in the same time, we've had around 4,000 diet related deaths due to cardiovascular disease alone.


----------



## elacsaplau (22 May 2020)

Leo said:


> That's actually an interesting point.



Jeepers, Leo - you sound surprised?!


----------



## Leo (22 May 2020)

elacsaplau said:


> Jeepers, Leo - you sound surprised?!



Sorry!! That does read badly, doesn't it   Unintentional of course, you have lots of interesting points.


----------



## Brendan Burgess (22 May 2020)

Odea said:


> Based on the number of new cases per day in Ireland, say 70. What are the mathematical chances of me picking up Covid-19 if walking on a beach that had 3000 people on it?



Hi Odea

While the risk of getting it on a beach is very small, your mathematical approach is wrong. 


The number of new cases confirmed per day is completely irrelevant. 

Your risk of contracting Covid depends on the numbers of people you interact with, where you interact with them, and how you interact with them.   

But it's not just about you. 

It's about the community.   If you have a  1% chance of catching Covid, 50,000 Irish people will get it.

So it would still probably be worth ranking the activities in order of risk. 

1) extensive face to face contact with a lot of different people indoors 

to 

20) Walking on your own on a beach without any face to face contact 

Brendan


----------



## Purple (22 May 2020)

Brendan Burgess said:


> It's about the community. If you have a 1% chance of catching Covid, 50,000 Irish people will get it.


Sure, but your chance of getting it while engaging in a particular activity is far lower than that. Even if you do get it your chance of recovery is over 99% and if you don't have a pre-existing condition it's well over 99.8%.


----------



## Brendan Burgess (22 May 2020)

Purple said:


> your chance of getting it while engaging in a particular activity is far lower than that



Hi Purple

The mistake in a lot of people's thinking is "If I crash these lights the chances of being hit by a car are very small". 

Of course, if you do it a few times, you increase your chances. 

So walking on an empty beach and not touching anything is zero. 

Taking a packed Dart to go for a walk on the beach in Sutton is not negligible. 

You have to look  at all activities over the whole duration while Covid is live in the community to measure your chances of getting Covid. 

But I fully agree with you that for most of us, the consequences of getting it are not severe. 

Brendan


----------



## Sunny (22 May 2020)

Brendan Burgess said:


> Taking a packed Dart to go for a walk on the beach in Sutton is not negligible.
> 
> Brendan



And that's before you take into account the usual dangers of taking a Dart to Sutton!

I wonder what the risk is on crowded trains. London have been running packed tubes for weeks and yet did I read recently that London hasn't had a new case in a couple of days?


----------



## Duke of Marmalade (22 May 2020)

I like to go for a drive in the Dublin mountains, just up and around the Sally Gap and back home.  My understanding of the medical experts' advice is that this constitutes 0% risk for me and 0% risk for the community.  Yet, if it has not quite been banned, it is very heavily discouraged.

I understand that the rules had to be made in great haste but as time goes on they will have to stand up to rational justification.  
Signs are that the Sweden approach of focusing on social distancing without a lot of collateral rules, some of which like the travel restrictions are difficult to rationalise, is faring no worse than us with our strict lockdown approach.


----------

