Zinsser's scientific work focused on bacteriology and immunology and he is most associated with typhus, especially the form called Brill–Zinsser disease, his namesake. He isolated the typhus bacterium and developed a protective vaccine. He wrote several books about biology and bacteria, notably "Rats, Lice and History" (1935), a "biography" of typhus fever. Zinsser had a strong influence on the work of Albert Coons (1912–1978), who developed the technique of immunohistochemistry. Zinsser was a mentor to, and colleague of, John Franklin Enders, who was awarded the 1954 Nobel Prize in Physiology or Medicine (together with Frederick Chapman Robbins and Thomas Huckle Weller).