During the past year, the most notable developments in the field of immunizations occurred with vaccines forHaemophilus influenzaetype b. A third conjugate vaccine was licensed, and the age of immunization was first lowered from 18 to 15 months. Later in the year, two conjugate vaccines were licensed for use in infants commencing at 2 months of age. New developments in pertussis immunization include favorable results in Japan with an acellular pertussis vaccine in children over 2 years of age. New insights from further analyses of a landmark British epidemiologic study indicate that we do not know if pertussis encephalopathy exists, but if it does, then the occurrence is extremely rare. Measles also continues To be a significant problem in preschool children, resulting mainly from failure of vaccine delivery to children in inner cities. Second doses should provide good control of breakthroughs in the teenage and young-adult group.