On Wednesday I watched a webminar given by the American epidemiologist Marc Lipsitch. It is part of a seminar series for physicists, on COVID-19. It was an interesting and sobering watch. I was struck by a comment Prof Lipsitch made in answer to one of the questions at the end of the webminar.
The comment was that it would really help if people, especially politicians and others who make decisions, just at a basic level understood that a majority, possibly a very large majority, of transmission is between two people who are close to each other. Perhaps in the same room, perhaps only a metre apart, but close to, not far from each other.
The concern is that a lot of people, including powerful politicians but also the general public, do not get this. Their mental model of how SARS-CoV-2 spread is not clear on this really important point. Maybe they have only a very hazy idea of how it spreads. This is despite the fact that this is really well established. We have a lot to learn about transmission but we really know that the risk shoots up whenever you get close to an infected person.
I thought of his point when watching rugby on TV a day a later. A rugby administrator was complaining about crowds not being able to come to stadiums to watch rugby. I can understand his frustration, professional sports rely on crowds to pay the bills and provide the atmosphere. But I worry that he does not get how SARS-CoV-2 spreads, and so does not get how risky crowding together 10,000 rugby fans is.
Chance & Necessity 