Not quite as simple as that. The infected patient coughs and a spray of droplets lands on a handle or arm-rest. The next passenger puts his hand on the arm-res

Not quite as simple as that. The infected patient coughs and a spray of droplets lands on a handle or arm-rest. The next passenger puts his hand on the arm-rest and then eats a packet of peanuts, thus transferring one person bodily fluids into a second person's bodily fluids.