Abstract
OBJECTIVE: To study a community outbreak of hepatitis A in a marginal population and the public health response in order to bring it under control. DESIGN: Descriptive study of the outbreak that occurred in February-June, 2004. An epidemiological survey was conducted to detect prior cases and active vigilance was set up. Case and susceptibility definitions were established. SETTING: A gypsy population in Madrid, Spain. They had basic provision of sewerage, water supply and waste disposal. PARTICIPANTS: A population of 550 in census; estimated population, 800. 70% were under 40 and 55% were illiterate. INTERVENTIONS: Control measures were: a) health education activities to strengthen habits of hygiene, and b) immunisation of susceptible individuals. A total of 646 people were vaccinated, with the active help of staff from the Institute of Rehousing and Integration into Society. RESULTS: The outbreak affected 26 people, with an average age of 8 (95% CI, 6.2-9.8), similar distribution by sex and 3.3% attack rate. Fourteen cases were students at state schools, not all in the same classes. There were 7 pairs of siblings among the cases. The diagnosis was conformed by serology in 17 cases. Five needed hospital admission. CONCLUSIONS: The epidemic curve suggested person-person transmission. All those affected were under 20 years old. Vaccination was seen to be effective in controlling the outbreak. Interventions were assisted by intermediaries in order to respect the gypsies' cultural context and were well accepted.