Do tall people avoid the flu? 1

It is surprising how little basic research appears to have been done on routes of infection of contagious diseases. It is generally acknowledged that the major routes are:

• Droplets
• Aerosols
• Surfaces

The relative importance of each route makes a huge difference to how contagion is controlled and getting it wrong can actually make things worse.

If the main route is droplet transmission, then simple separation distance would help. There is some evidence for this and often a one meter distance is recommended. Direct physical barriers like plastic screens would help as would the use of (surgical ) masks worn by the infected person. Also putting hour hand in front of your mouth when coughing would help – a bit like a baseball mitt.

The classic picture above is actually quite misleading, as the natural action with sneezing is for the head to initially tip back, but actually tilt forward during the sneeze. Most of the large droplets are directed towards the floor.

However, reducing contagion by one route can increase it by another, particularly with droplets.

A hand in front of the mouth reduces droplet transmission, but now you have a contaminated hand – touching surfaces and contaminating other objects like money, door handles , switches, and documents. Elbow coughing is better, but its real importance is unknown.

If aerosols are also important, then a sneeze barrier may reduce the contamination of the person behind the barrier to droplets, but air flowing over, under or around the barrier tends to curl towards the person, increasing the hazard.

Also, if droplets are more important than aerosols, then height should confer some protection to taller people, and things like high heels and elevated work surfaces should give some protection for people dealing with potentially infected people. The effect is doubled if tall people are less affected, since short infected people would tend to infect short people, but the tallest infected people would tend to infect everyone.