It has been shown by Mitus and her associates1-3 that infection with measles virus in children with acute leukemia may occasionally terminate fatally. At autopsy in such cases, pathological changes characteristic of giant-cell pneumonia are present. The etiologic agent in all cases of this condition examined thus far has proved to be measles virus. These workers also found that prophylactic administration of γ-globulin cannot be relied upon to prevent the development of measles giant-cell pneumonia.
Accordingly, the possibility of protecting this unusually vulnerable sort of patient by means of vaccination with attenuated measles virus vaccine was considered. The decision to vaccinate a small selected group of children was taken only after carefully weighing the possible untoward effects of the vaccine against the grave risk attendant upon infection naturally acquired.
In the first part of this communication, abnormal as well as normal reactions to measles of different children with acute