Where was the first vaccine against yellow fever developed?

The first effective yellow fever vaccine was developed in the United States in the 1930s, with major work by Max Theiler at the Rockefeller Foundation. The key 17D vaccine was introduced in 1937 and later became one of the most important tools against the disease. Yellow fever is transmitted by mosquitoes and can cause severe hemorrhagic illness. Vaccination campaigns have been central to controlling outbreaks in Africa and South America. Theiler received the Nobel Prize in 1951 for his work.