[Descriptive study of hepatitis outbreaks occurring in Catalonia (1999-2003)]. / Estudio descriptivo de los brotes de hepatitis A investigados en Cataluña (1999-2003).

BACKGROUND AND OBJECTIVE: The currently low endemic level of hepatitis A in Spain favors manifestation of the disease as outbreaks among specific risk groups. The aim of this study is to analyze the hepatitis A outbreaks investigated in Catalonia (Spain) during the period of 1999 to 2003. METHODS: The criteria for including an outbreak were defined and outbreaks were classified according to the type of transmission. The variables analyzed were space, time, socio-demographic parameters, setting, risk factors, and preventive measures adopted. The incidence rate and rate ratio were calculated according to age and sex. RESULTS: Among 74 outbreaks, 73 fulfilled the inclusion criteria. Most outbreaks involved person-to-person transmission (83.8%) and the rest had a common source of infection (14.9%). In total, 334 cases were included (cumulative incidence 1999-2003: 5.27 per 100,000 inhabitants), with an average age of 24.5 years. The settings yielding the most cases were family (143), community (97) and schools/preschools (87). The number of cases per outbreak ranged from 2 to 11, except one outbreak that occurred in 83 young homosexual men with high-risk sexual practices. The main factors related to the case index or to coprimary cases included belonging to age groups with low immunity (children and young adults) and travelling to or from endemic areas. CONCLUSION: Hepatitis A outbreaks in Catalonia are still frequent. They mainly occur in the family environment, by person-to-person transmission and in the most vulnerable groups (preschool or school employees, travelers, and men who perform high-risk sexual practices with other men).

Estudio descriptivo de los brotes de hepatitis A investigados en Cataluña (1999-2003) / Descriptive study of hepatitis outbreaks occurring in Catalonia (1999-2003)

Antecedentes y objetivo. Actualmente España presenta un patrón de baja endemicidad de hepatitis A que favorece que la enfermedad se manifieste en forma de brotes en colectivos susceptibles. El objetivo de este estudio es analizar los brotes de hepatitis A investigados en Cataluña durante el período 1999-2003. Métodos. Se definieron criterios para la inclusión de los brotes y posteriormente se clasificaron según el mecanismo de transmisión. Se analizaron variables de espacio, tiempo, sociodemográficas, ámbito, factores de riesgo y medidas preventivas. Se calcularon las tasas de incidencia y la razón de tasas según edad y sexo. Resultados. De 74 brotes, 73 cumplieron los criterios de inclusión: la mayoría con transmisión persona-persona (83,8%) y el resto con fuente de infección común (14,9%). En total, se incluyeron 334 casos (incidencia acumulada 1999-2003:5,27 por 100.000 habitantes), con una mediana de edad de 24,5 años. Los ámbitos con más casos fueron el familiar (143), el comunitario (97) y el escolar/guardería (87). El número de casos por brote osciló entre 2 y 11, excepto un brote que afectó a 83 varones con prácticas homosexuales de riesgo. Pertenecer a los grupos de edad de baja inmunidad (niños y adultos jóvenes) y viajar o proceder de zonas endémicas fueron las características más importantes relacionadas con el caso índice y/o con los casos coprimarios. Conclusión. Los brotes de hepatitis A en Cataluña todavía son frecuentes. La mayoría se producen en el ámbito familiar, por transmisión persona-persona, y en los subgrupos de población más susceptibles a la infección (trabajadores de guarderías o escuelas, viajeros y varones con prácticas homosexuales de riesgo) (AU)

Background and objective. The currently low endemic level of hepatitis A in Spain favors manifestation of the disease as outbreaks among specific risk groups. The aim of this study is to analyze the hepatitis A outbreaks investigated in Catalonia (Spain) during the period of 1999 to 2003. Methods. The criteria for including an outbreak were defined and outbreaks were classified according to the type of transmission. The variables analyzed were space, time, socio-demographic parameters, setting, risk factors, and preventive measures adopted. The incidence rate and rate ratio were calculated according to age and sex. Results. Among 74 outbreaks, 73 fulfilled the inclusion criteria. Most outbreaks involved person-to-person transmission (83.8%) and the rest had a common source of infection (14.9%). In total, 334 cases were included (cumulative incidence 1999-2003: 5.27 per 100,000 inhabitants), with an average age of 24.5 years. The settings yielding the most cases were family (143), community (97) and schools/preschools (87). The number of cases per outbreak ranged from 2 to 11, except one outbreak that occurred in 83 young homosexual men with high-risk sexual practices. The main factors related to the case index or to coprimary cases included belonging to age groups with low immunity (children and young adults) and travelling to or from endemic areas. Conclusion. Hepatitis A outbreaks in Catalonia are still frequent. They mainly occur in the family environment, by person-to-person transmission and in the most vulnerable groups (preschool or school employees, travelers, and men who perform high-risk sexual practices with other men) (AU)