The Kansas City City Chiefs went on to win the 2024 Super Bowl, but part of the way through the match both the team as a whole and their player Travis Kelce were up against it. Under huge pressure, Kelce gave the Chiefs’ coach, Andy Reid, both barrels from up close – see image above. Kelce apologised afterwards, and the coach seemed relatively unbothered. The incident is sufficiently famous that it has spawned memes, and a meme generator. My attempt at a meme is above: Kelce and Reid illustrate almost perfectly the ideal setup for one person, here Kelce, to transmit an airborne disease such as COVID-19 or flu, to another person, here Reid.
COVID-19 and flu are transmitted in aerosol particles that leave an infected person in their breath. It is known that speaking, especially speaking loudly as Kelce is doing, increases the amount of aerosol particles in your breath. The forces in the respiratory tract are presumably larger and these shake loose more tiny particles of mucus, some of which may contain virus – if you are infected. So it is likely that people shouting are more infectious than those who are quiet.
It is also true that being up close and face-to-face – as Kelce and Reid are – is likely to maximise the amount of aerosol breathed out by one person that is breathed in by the other. Above, when Reid draws breath, he is directly breathing in air that Kelce has just expelled while shouting at him. So perhaps 10% or more of the air Reid breathes in, was just breathed out by Kelce. While if two people are far apart then the air breathed out by one person mixes in with the surrounding air and so is heavily diluted before the second person breathes it in.
So if you want to remember what situation poses the highest risk of transmission of COVID-19, flu and other airborne diseases, think of Travis Kelce and Andy Reid, and the 2024 Super Bowl.
Chance & Necessity 