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Sunday, May 03, 2020

Responsible private behavior in a viral pandemic

I’m trying to figure out how to apply Kant’s categorical imperative to the present situation of viral pandemic. How should I behave such that I would be ok if everyone behaved in the same way as I do? I should also specify that although I hope that I won’t personally get covid-19, I think of myself as in the low risk group, so my own health is not my primary concern. (Of course, If I get very sick, this attitude would change quickly.)

To make it simple, I’d like to allow two types of behavior regarding care in minimizing spread of the virus. With the public (large numbers of people), I am very careful. I don’t go to a large gathering without a mask, shaking many people’s hands, hugging them, and generally sneezing and touching many surfaces over an extended period of time. When I go to the grocery store, I wear a mask and keep my distance. I wash my hands before and after (or wear gloves).

Next, there are a small number of people that I do not practice such a careful approach with. If I were quarantined with my family, that would be the model, but as I am by myself, I should be allowed a certain number of people to see that I have a higher chance of spreading or recieving the virus from. I want to behave in such a way that if everyone followed similar principles, the virus would stay contained and the number of cases would go to zero. Suppose we know the probability of spreading the virus publicly (p_pub) and the number of people I interact with in the public (n_pub). And likewise we know the probability of spreading the virus privately (p_priv) and the nunber of people we interact with privately. From our assumptions, n_pub >> n_priv and p_pub << p_priv. Suppose that for everyone, these numbers were the same (clearly not true, but fits with the Kantian thought experiment). If we know n_pub and p_pub and p_priv what is n_priv so that the global R_0, (the average number of persons infected per infected individual) is less than 1?


Jeff Hall said...

Hi Boaz,
Great question. It makes me wonder if a distinction can really be made between p_pub and p_priv. We are all social beings and come within 6 ft of other persons all the time, even if accidentally. Certainly, if p_priv is controlled under strict quarantine controls, where each member of the private group never even approaches another person outside of the group, wears highly effective masks and never touches a surface that an infected person has touched within the past several days, then a point can be made about there being a difference between p_priv and p_pub.

I'm guessing that we would like to feel safe with those in our private group. We certainly don't want to be quarantined from those that we love and don't want to live in a plastic bubble separated from our families. I guess my question is: Can we ever be assured that all the members in our private groups are taking the same level of precautions that we are? All it takes is for one child to touch another child's toy outside of the group.

The other day, I was given a reminder of how we unknowingly share the same air. I was jogging and there were some construction guys across the street (about 40 feet away). One of the guys was smoking a cigarette. There was a slight breeze from them to me. As I was jogging by, I got a lung full of cigarette smoke even though I was wearing a mask. I know that if I were wearing a more effective mask, say N95 with good face sealing and fit, I probably would not have smelled the smoke.

I'm certainly not paranoid about the virus nor am I trying to promote a view that encourages that. All we can do is to do the recommended safety practices.

I like the model and I think that if Ro is going to get below 1, then everyone is going to have to take all the reasonable precautions that they can. For Colorado, the number of daily cases does appear to be dropping slightly but very slowly so what we are doing collectively seems to have a Ro slightly below 1.

??? said...

Good points, Jeff. Thanks for the response! I agree that we can't know whether someone in our private group will get the virus or actually be a much larger spreader than we imagine. I think it may still be correct probabilisticly on a larger scale.

Interesting about smelling cigarette smoke from 40 feet away. I guess there is a question as to whether the virus could hitch a ride on the cigarette smoke particles...
I haven't looked into it!

If I have a chance to think about this more I'll post a follow up!