The February issue of Addiction reports results from the systematic review by Larney  which, due to the scarcity of studies, provide limited support for opioid substitution treatment as a method for reducing injecting-related human immunodeficiency virus (HIV) and therefore hepatitis B virus (HBV) risk behaviours in prison. Justifiably, the editorial by Farrel, Strang & Stover on the same issue  supports HBV vaccination for inmates as a targeted universal harm reduction (HR) intervention to overcome existing barriers to the implementation of HBV risk reduction measures in prison.
Many HBV cases still occur during prison stay due to persisting unsafe injecting and sexual practices , but these could be prevented by an adequate HBV vaccination strategy . The MANIF 2000 cohort data show that among 467 HIV-infected injecting drug users (IDUs), only 35 were HBV-negative and the two major risk factors associated independently with HBV-seropositivity were older age and a history of incarceration. Since 1993 French public health authorities have recommended systematic hepatitis B vaccination in groups at high risk of transmission, including injecting drug users (IDU) and HIV-infected patients. However, a retrospective analysis performed on sera of the 35 HBV-negative patients showed that three experienced HBV seroconversion during follow-up, with an incidence rate of 3.4 per 100 person-years; two of these three patients reported sexual risk behaviours only.
One previous survey also revealed that French IDUs were less likely to be vaccinated against hepatitis B than the general population , while other research has shown that hepatitis B vaccination can be feasible and effective among drug users  and prisoners . The editorial also emphasizes that there is a broad but not ‘universal’ consensus on hepatitis B vaccination.
In effect, since 1990 the French HBV vaccine campaign has faced public and professional doubts about the potential link between HBV vaccination and onset of central nervous system (CNS) inflammatory demyelination . To what extent this association may influence HBV vaccination in prison settings is difficult to say. At any rate, the proportion of inmates vaccinated against HBV upon prison entry increased from 13.7% in 1997 to 31.3% in 2003 , probably thanks to the HBV vaccination campaign in the general population. However, updated information about HBV vaccination in French prisons is needed. Although the French National Authority for Health (HAS) guidelines in 2003  recommended HBV vaccination strongly in prisoners, the 2004 HAS guidelines  mitigated the content of the former, suggesting that decisions about HBV vaccination should take into account individual risks and community benefits. It is possible that the difficulty in realizing a full immunization programme for prisoners may be an additional barrier. Nevertheless, equivalent accelerated strategies based on injection at days 0, 10 and 21 are effective and need to be promoted [7,12].
Full integration of HBV vaccination in a package of HR measures is not only a major public health opportunity in drug users and HIV-infected individuals but a priority in prison settings, where the efficacy of other HR measures may also need further research.