THE present study was designed to assess the effectiveness of measles vaccine (attenuated) among normal children living at home and exposed to the usual sibling or school measles contacts, to define the reactions encountered and the serologic response and to determine parent acceptance of this immunizing agent.MethodsFamilies enrolled in a special teaching program for medical students and house officers in training, the Family Health Care Program, were selected for the study when 2 or more children in a family gave no previous history of measles. This history was considered to be unusually accurate because most of these children . . .