Task profile and risk of occupational hepatitis A infection in sewerage workers

Abstract

Objective: The aim of the study was to assess to what extent parameters of task-related occupational exposure influence anti-hepatitis A virus (anti-HAV) seroprevalence in sewerage workers, using a new instrument for classification of exposure. Methods: A new instrument for the assessment of work-related infection hazards was developed based on expert interviews, evaluation of literature and theoretical considerations. It was included in a questionnaire for collecting detailed information on occupational exposure, safety awareness, safety behaviour and socio-demography. Anti-HAV status was assessed for all (n=343) (non-vaccinated) study participants. Results: Marked differences in task profile and task-related exposure within the group of sewerage workers were found, underlining the necessity of a detailed exposure analysis. In a multivariate model three risk factors that were related significantly to anti-HAV positivity were identified: age, country of origin and task-related exposure. Conclusions: Since task profiles and occupational exposure differ strongly within the job category of sewerage workers, evaluation of endangerment has to reflect individual task-related exposure. The task-exposure matrix developed and presented in this study is a practicable and valid instrument for exposure assessment and may be used for the exposure analysis of further biological agents in this working environment. Besides the known risk parameters age and origin, our study demonstrates a dose-response relationship between the degree of occupational exposure and the anti-HAV seroprevalence. Therefore, an effective worksite HAV-prevention programme should consider all technical, structural and educational measures that help to reduce individual exposure.