The Edmonston B vaccine was already known to result in higher fevers and rash, especially when given to such populations. For example, two years before Neel administered the vaccine to the Yanomamö, Dr. Francis Black, a geneticist at Yale, had chosen the more attenuated Schwarz vaccine to give to the Tiriyo Indians in Brazil. In describing studies of measles vaccines in indigenous American populations, Black wrote that in the case of Panamanian Indians, Edmonston B's "rather high reaction rate might be considered a contraindication," and among Alaskan Eskimos "a serious impediment." Moreover, in Venezuela at the time, the government's own vaccination program was using the widely available Schwarz vaccine in three diluted doses, on the advice of the Centers for Disease Control, in Atlanta. The Edmonston B vaccine is no longer in use anywhere in the world.