Popular People and the Pandemic: A Selection from Nicholas A. Christakis’s Apollo’s Arrow (2020)

“Some cases of super-spreading may relate simply to the fact that some people come into contact with a great number of other people in the routine course of their lives or they may have more social connections. To be fair, popular people are more likely to become infected themselves as well as more likely to infect numerous others (illustrated by the many politicians and actors who were infected early in the COVID-19 pandemic). . . .

People with many connections . . . tend to be infected earlier in the course of an epidemic than random people chosen from the same population. Because of their many social interactions, popular people have an increased risk of exposure. . . .

But this also means that popular people are more likely to become immune early on in the course of an epidemic. And if all the popular people became immune early, relatively more paths for the virus to spread through society would be cut off.

Unpopular people are less concerning from an epidemic-control point of view because they intrinsically infect fewer other people, so their immunity matters less. This also means, incidentally, that vaccinating people with many connections is more helpful than vaccinating people with few connections.

It’s difficult to estimate the precise size of the effect since it depends on many factors. But the implication for reaching the herd-immunity threshold is that if the more popular people are overrepresented early on during the COVID-19 pandemic, a lower percentage of the whole population must become immune—perhaps only 40 to 50 percent.”—Nicholas A. Christakis, Apollo’s Arrow: The Profound and Enduring Impact of the Coronavirus on the Way We Live (2020)