[Transmission of measles during four outbreaks in a partially vaccinated population].

All measles cases occurred between 1989 and 1991 in the territory of the Local Health Unit 10--Marche Region--Italy, were studied in order to evaluate the characteristics of the disease and the transmission mechanisms. A total of 4 outbreaks were evidenced: 2 occurred in a 40,000 population municipality (with 46 and 87 cases, respectively), 1 in a 10,000 population municipality (with 35 cases) and 1 in two closely-related municipalities of 4,600 population (with 67 cases). The immune status of children between 1 and 10 years of age was evaluated adding the number of vaccinated children to the number of those who resulted having had the disease. Immune children were between 52.3% and 89.1%. During the outbreaks, the percentage of cases occurred in subjects over 10 years of age was, in total, 65.5. No cases needed hospitalization and only one case occurred in a vaccinated boy. In 189 cases the subject who presumably transmitted the disease was identified. Transmission occurred: within the school in 51.8% of the cases; within the family in 30.7%; during social activity in 10.0%; from inhabitants of the same house in 7.4%. The epidemiology of measles, in the area of this study, seems different from that described in the United States.