The long read: When he was six, Paul Alexander contracted polio and was paralysed for life. Today he is 74, and one of the last people in the world still using an iron lung. But after surviving one deadly outbreak, he did not expect to find himself threatened by another

Martha Lillard spends half of every day with her body encapsulated in a half-century old machine that forces her to breathe. Only her head sticks out of the end of the antique iron lung. On the other end, a motorized lever pulls the leather bellows, creating negative pressure that induces her lungs to suck in air.