A primary driver of the monumental endeavour to develop the yellow fever vaccine was a shared sense of responsibility that America, having the means and knowledge, should use its resources for the good of all. That sense of responsibility is now waning.

Max Theiler is the first of 13 South Africans to receive a Nobel Prize (1951, physiology and medicine) for developing what became known as an attenuated vaccine for yellow fever. His discovery changed the course of medicine as it treated, cured and prevented the deaths of thousands upon thousands of people. His Swiss-born father, Sir Arnold Theiler, was the inaugural director of the Onderstepoort Veterinary Research Institute outside Pretoria.

Theiler's discovery, developed while he was researching at the Rockefeller Foundation laboratories in New York, was a breakthrough answer to the challenge the US Army had in protecting their soldiers against yellow fever. Military medical data from the Spanish-American War of 1898 revealed that more soldiers died from disease than in battle. Of these, yellow fever was among the most devastating, following a swift and virulent course.

In response to this urgent threat, the US Army chose to mobilise science. In 1900, army surgeon Walter Reed, namesake of the...