In this post, I will explain why it is important not only that we cancel large conferences and other events, we should also curtail medium and even small gatherings that are non-essential.
Joshua Weitz has done a great service by explaining how the probability that one or more participants in an event is infected scales with the size of the gathering. In brief, even when the vast majority of people are not infected, the chance that somebody is infected goes up as the number of participants gets larger. I think most people are also now coming to grips with the rapid growth of this outbreak, which means that a meeting with relatively low risk today might be a very bad idea a month from now.
But does this mean that medium-sized and small events can proceed without worry? No. Let me explain why even these events should be reduced to the bare minimum that are essential. Most of my readers are fellow scientists, so what follows is cast in the language of conferences and departmental seminars—but hopefully others can relate these to similarly sized gatherings in their own lives.
Ok, to begin. You’re very pleased to hear that the conference you had planned to attend next month was canceled. With 10,000 attendees, and with infections doubling every week, it was clearly smart to cancel such a large conference. But your departmental research seminar is attended by only 100 people. Surely that can safely continue, right?
If only your department had a seminar, and if it was a one-time event, then sure, why not. However, there are 25 other departments around the country in your field of study alone, and each of the departments has planned 4 weekly talks over the coming month. Seen in that light, it’s like that large conference of 10,000 — except that its 25 x 4 = 100 events with 100 attendees each. In other words, there are 10,000 potential transmissions of the viral infection.
In general, as event sizes get larger (more participants), the frequency and number of those events becomes smaller. I don’t have data to back this up (maybe somebody does), but I’d bet that the number of small gatherings increases even faster than the number of participants falls off. For example, for every conference of 10,000 people, I expect there are even more than 100 meetings of 100 people.
Therefore, reducing non-essential gatherings of all sizes should be part of our individual and collective efforts at social distancing. It’s no fun, I know. But it’s one of the best ways we can ward off this beast of a virus, and thereby protect our colleagues, our friends and families, and our communities.
[This image shows the actor Rowan Atkinson (aka Mr. Bean). It is used here under the doctrine of fair use.]