Hepatitis A in urban Ireland

Aims: To determine the prevalence of immunity to hepatitis A virus (HAV) in fection in urban Ireland and to categorize the region into low, intermediat e or high HAV endemicity, and to analyse the significance of certain common ly associated risk factors. Methods: Two hundred and thirty three volunteers were recruited from 6 gene ral practices in Dublin, Ireland. There were 44 volunteers in the 10 to 19 yr age group, 40 in the 20 to 29, 42 in the 30 to 39, 43 in the 40 to 49 an d 64 in the over 50 age groups, Each participant completed a detailed quest ionnaire and was tested for anti-HAV total antibody (primarily IgG) using a competitive ELISA assay. Urban Ireland was classified into the appropriate area of HAV endemicity according to the prevalence of immunity by age grou p. Risk factor differences were analysed for significance using the chi squ are test and Fisher's exact test. Results: One hundred and fifty seven (67 per cent) volunteers were immune, of whom 20 (45 per cent) were in the 10 to 19 yr age group, 17 (43 per cent ) in the 20 to 29, 30 (71 per cent) in the 30 to 39, 34 (79 per cent) in th e 40 to 49 and 59 (92 per cent) in the over 50 age groups. Fifty-five per c ent of the individuals studied below the age of 20 yr were non-immune. The immune rates over the age of 30 were significantly greater (p<0.01) than th ose in the 10 to 29 age groups. Socioeconomic pattern in the total and 10 t o 19 yr age group was a significant (p<0.0002, p<0.004 respectively) risk f actor for infection. Conclusion: This study concludes that urban Ireland is an area of low HAV e ndemicity with age and socioeconomic status as the significant influences o n seropositivity, This survey provides an insight into the changing epidemi ology of HAV infection in Ireland and serves as a guide for immunisation of at risk population groups.