Broader vaccination of expatriates against HBV infection: do we reach those at highest risk?

Abstract

Several studies have indicated that expatriates and travellers to hepatitis B virus (HBV) endemic areas, because of their sexual behaviour in the country of posting, are at high risk for HBV infection. [1][2][3][4][5][6] After return to their country of origin they may introduce HBV in the general population. 3,7,8 Therefore, active research into risk determinants for HBV infection is essential in order to guide health education campaigns and vaccinations programmes directed at these groups.In a previous study in 1987-1989 among 2391 Dutch expatriates returning from sub-Saharan Africa, 160 (6.7%) were found to be HBV-infected, probably through unprotected sex or medical exposure. Independent risk factors for HBV infection were: age (risk increases with age), length of stay (risk increases with length of stay), number of needlesticks, number of African sexual partners and having an African life partner. 4 As a consequence of these results, a Dutch vaccination strategy was implemented in 1991, in which travellers to high endemic areas (Ͼ8% chronic HBV carriers) and expatriates going to middle (2-7% chronic HBV carriers) and high endemic areas were advised to be vaccinated. Moreover, education campaigns on condom use were directed at travellers and expatriates.In this study the effect of the new strategy on the prevalence of HBV infection was assessed among 864 expatriates (covering the period from July 1994 to February 1996). 9,10 The following questions were addressed:Did the new vaccination strategy have an impact on the proportion of expatriates vaccinated, as compared to the previous study from 1987-1989? If so, did it decrease the number of HBV-infected expatriates?Did the new vaccination strategy reach the expatriates at risk, e.g. those with high sexual or medical risk behaviour?The results from this study can be used to optimize the current vaccination strategy.