Epidemiology of Hepatitis B Virus Infection in The Netherlands and Beyond

Abstract

This Thesis resulted from a decade of studying the epidemiology of hepatitis B virus (HBV) infection in the Netherlands, England and Wales and at a European level, starting in 2003. The studies aimed to improve the knowledge of the local epidemiology of HBV and to assess the effectiveness of HBV vaccination programmes, in order to inform public health policy for prevention and control of HBV and its associated burden of disease and death in the Netherlands and elsewhere.

HBV causes hepatitis and can be transmitted between humans. HBV infection can resolve or result in chronic infection. The latter can lead to cirrhosis and hepatocellular carcinoma (HCC), which is often fatal. Safe and effective vaccines to prevent HBV infection have been available since 1982.

The first eight papers in this Thesis cover the epidemiology of HBV infection in The Netherlands. It is among countries with the lowest HBV prevalence in the world. First-generation adult migrants (FGMs) have a 13-fold greater risk of being HBsAg- and/or HBV-DNA-positive than indigenous Dutch participants, and are the main target group for secondary HBV prevention. Men who have sex with men (MSM) are at high risk of HBV infection. Children, adult females and heterosexual males with parents born in a hepatitis B endemic country are also at increased risk. The HBV vaccination programme for behavioural high-risk groups has effectively reduced the incidence of HBV infection in the Netherlands, mainly by preventing infections among MSM. Effectiveness of such a programme on a national level was never demonstrated before.

The HBV vaccination programme for children of HBsAg-positive mother is effective. Children born to Chinese women are at increased risk of perinatal infection.

The HBV 2003-2007 vaccination programme for children of migrants has probably been effective and highly acceptable to parents. The vaccine used in this programme is currently used for all infants in The Netherlands. It achieved target thresholds for immune responses for all antigens that were studied.

Studies carried out in England & Wales in the early 2000s estimated that the annual incidence of HBV infection in England & Wales was 7.4 per 100,000 (adjusted for underreporting and asymptomatic infections), with injecting drug use the most frequently reported route of transmission. Transmission during childhood was rarely reported, but was more frequent among South Asians. The incidence in South Asians was relatively high, particularly among children. Endemic transmission gives rise to only a small proportion of all new chronic infections, with the vast majority arising from immigration of established HBV carriers.

We studied HBV and hepatitis C virus (HCV) prevalence and cost-effectiveness of screening in 34 European countries. We concluded that the prevalence of chronic HBV and HCV infection varies widely between European countries. Anti-HCV-Ab screening of IDUs and HBsAg screening of pregnant women are European Public Health priorities. HBsAg screening of migrants is likely to be cost-effective.

Lastly, the Thesis provides a summary of what it adds to what was already known, its implications for HBV surveillance and research, and recommendations for prevention and control of HBV.