British bacteriologist and immunologist best known for advancing vaccination through the use of autogenous vaccines (prepared from the bacteria harboured by the patient) and through antityphoid immunization with typhoid bacilli killed by heat.

Wright received his medical degree at Trinity College, Dublin, in 1883. He continued his education at Leipzig, Marburg, and Strasbourg and taught at several universities before he was appointed professor of pathology at the Army Medical School, Netley, in 1892. There he developed a vaccine against typhoid (typhoid fever) that was tested on more than 3,000 soldiers in India and used successfully during the South African (Boer) War. As a result Britain was the sole combatant to enter World War I with its troops immunized against typhoid fever—a factor that was instrumental in making this the first war in which fewer British soldiers died from infection than from missiles. Wright served in France during the war investigating wound infections.

Wright resigned from the army in 1902 and became a professor of pathology at St. Mary's Hospital in London that same year. Wright conducted research there until his retirement in 1946. Alexander Fleming, who later developed penicillin, was one of his aides. Wright also developed vaccines against enteric tuberculosis and pneumonia and contributed greatly to the study of opsonins, blood enzymes that make bacteria more susceptible to phagocytosis by white cells. Knighted in 1906, he was sometimes known as “Sir Almost Right” and was characterized in George Bernard Shaw's play The Doctor's Dilemma as Sir Colenso Ridgeon.