I just finished reading a book, “The Fantastic Laboratory of Dr Wiegl” by Arthur Allen, that describes the work that Weigl did before and during WWII. I thought the book did a really good job describing the affects of typhus and the reasons developing a vaccine was so difficult.
Despite the title, only about half the book is about Wiegl. The other half is about Ludwick Fleck. Fleck was jewish and a former colleague of Wiegl’s who also developed a typhus vaccine.