High impact of migration on the prevalence of chronic hepatitis B in the Netherlands.

OBJECTIVES

A representative serosurveillance study (1995) resulted in an estimate of 0.2% for the HBsAg prevalence in the Netherlands. Some risk groups, especially migrants, were not well represented in the study, which probably led to an underestimation of the true HBsAg prevalence. The aim of this study was to calculate an adjusted HBsAg prevalence estimate for the total Dutch population including these risk groups.

METHODS

According to their country of origin first-generation migrants (FGM) were classified into groups with low, intermediate and high prevalence using data from the WHO and Statistics Netherlands. The number of chronic HBsAg carriers in different age and population groups was estimated based on studies about age-specific prevalence in different countries. The number of carriers in the indigenous population was estimated using the serosurveillance study. A combination of these estimates led to an estimate of the total prevalence rate in the Netherlands.

RESULTS

Nearly 10% of the Dutch population are FGM. Of these, about 18% were born in low-endemic, 71% in middle-endemic and 11% in high-endemic countries. The overall prevalence of HBsAg in FGM is estimated to be at 3.77%. Combining these results with the results of the serosurveillance study the HBsAg prevalence in the Dutch population is estimated to be between 0.32 and 0.51%, and when including injecting drug users and mentally handicapped persons the prevalence rates are 0.36 and 0.55%, respectively.

CONCLUSION

Our results show the high importance of targeting migrants and their close contacts adequately in screening programmes, vaccination and treatment for chronic hepatitis B.