Rudolf Weigl
Built a typhus vaccine using lice he fed on his own skin, then used the lab to shelter people from the Nazis
Rudolf Weigl was born in 1883 in Przerów, in what was then Austria-Hungary, and trained as a biologist at the University of Lwów, where he later became a professor. He became fascinated by epidemic typhus, a disease spread by lice that killed enormous numbers of soldiers and civilians during the First World War and its aftermath, with no effective vaccine available.
Through the 1920s he worked out a method for growing the typhus bacterium inside the guts of live lice, which had to be fed on blood, and developed a technique of raising colonies of lice in small cages strapped to the legs of human volunteers, or "feeders," so the insects could feed on human blood without spreading disease. He used the resulting infected lice to produce a working vaccine.
When Nazi Germany occupied Lwów during the Second World War, the vaccine was in high demand, and Weigl was allowed to keep his institute running. He used the position to employ Jewish scientists and intellectuals as lice feeders and laboratory staff, positions that came with papers protecting them from deportation, and secretly diverted vaccine batches to the Warsaw Ghetto and Polish resistance networks rather than only to German forces as ordered.
Historians estimate his institute saved several thousand people this way. He continued working after the war and died in 1957.