Hepatitis A antibody prevalence among people with an intellectual disability in Ireland

This manuscript aims to determine the prevalence of antibody to and risk factors for hepatitis A virus (HAV) in individuals attending three intellectual disability services through a cross-sectional survey held in Dublin, Ireland. Participants were 636 individuals aged four to 78 years attending three intellectual disability services. The main outcome measure was the measurement of anti-HAV (IgG antibody) in oral fluid swabs using an antibody capture enzyme immunoassay (EIA) technique. Risk factor information was obtained by questionnaire from the individual’s medical record. Participants were 362 males and 274 females. The median age was 36 years. The median age of the individuals differed significantly from one institution to another (P<0.001). The prevalence of antibody to HAV was 43% overall but the individual levels for the three institutions were 65%, 30% and 68% respectively, the difference being statistically significant (P<0.05). Although a number of factors were statistically significantly associated with prevalence of antibody on univariate analysis, only age was associated with the prevalence of antibody on multivariate analysis. Among clients living at home, both age and use of respite care were associated with having antibodies to HAV. In conclusion, the prevalence of antibody increased with age and 14% had evidence of infection in the first ten years of life. We recommend that consideration should be given to immunising new entrants to the service with the combined hepatitis A and B vaccine.