Migrants and hepatitis B: new strategies for secondary prevention needed

Migration of individuals with chronic hepatitis B virus (HBV) infection from endemic countries contributes substantially to the prevalence of chronic HBV infection in low-endemic countries.1 This is reflected in case notifications where chronic infections are frequently reported in first generation migrants and the high diversity of HBV genotypes found in chronic infections in The Netherlands.2,3 Consequently, the burden of illness caused by chronic HBV infection in low-endemic countries is largely carried by first generation migrants. Now that in recent years treatment for chronic HBV infection has improved with new antiviral drugs such as adefovir, entecavir and tenofovir becoming available, the question arises whether an active effort should be undertaken to identify individuals with chronic HBV infection so that they can be offered treatment. This would benefit the patient and is likely to reduce the burden of illness and costs for the health care system of long-term complications due to chronic HBV infection.4 In addition, it might prevent onward transmission of HBV by reducing the viral load and hence infectivity of chronic infections, and when susceptible contacts of individuals with chronic infection are vaccinated. Investigation of transmission routes in notified acute infections in the Netherlands showed that migrants from endemic regions were the source of infection in nearly a quarter of cases, where HBV was sexually acquired.2 A recent economic analysis of screening and treatment of migrant populations for chronic HBV suggests that this is a cost-effective intervention (I.K. Veldhuijzen et al., personal communication). It may also help to reduce inequity in health care provision, as currently chronic HBV infections in migrants are less likely to be detected than those in other high-risk populations, such as men who have sex with men or injecting drug users, who in the Netherlands are targeted for screening and vaccination. Options for implementation of a HBV screening programme that explicitly targets migrants from endemic countries include population based and opportunistic screening. Alternatively, enhanced contact tracing might identify substantial numbers of chronically infected individuals. The latter may be more efficient than screening due to improved compliance. In addition to exploring screening options, evidence also needs to be gathered on cost-effectiveness of different options for HBV vaccination, e.g. of those screened who are susceptible and for contacts of individuals with chronic infection. Considering that the prevalence of HCV is also increased in some migrant populations,5 the question arises whether combined screening for chronic HBV and HCV would be opportune. More research is needed to compare costs and benefits of various strategies; but at the same time, public health action towards those who are at highest risk to suffer from long-term complications of chronic HBV infection is called for. Migrants are a vulnerable population subgroup who will have immediate benefit from a more active approach regarding hepatitis B and C screening and treatment, while indirect effects of treatment through lowering transmission rates and decreasing the burden of illness is likely to be of additional public health benefit.