Targeted outreach hepatitis B vaccination program in high-risk adults: The fundamental challenge of the last mile

The aim of this study was to evaluate the cost-effectiveness of the on-going decentralised targeted hepatitis B vaccination program for behavioural high-risk groups operated by regional public health services in the Netherlands since 1-November-2002. Target groups for free vaccination are men having sex with men (MSM), commercial sex workers (CSW) and hard drug users (HDU). Heterosexuals with a high partner change rate (HRP) were included until 1-November-2007.Based on participant, vaccination and serology data collected up to 31-December-2012, the number of participants and program costs were estimated. Observed anti-HBc prevalence was used to estimate the probability of susceptible individuals per risk-group to become infected with hepatitis B virus (HBV) in their remaining life. We distinguished two time-periods: 2002–2006 and 2007–2012, representing different recruitment strategies and target groups. Correcting for observed vaccination compliance, the number of future HBV-infections avoided was estimated per risk-group. By combining these numbers with estimates of life-years lost, quality-of-life losses and healthcare costs of HBV-infections - as obtained from a Markov model-, the benefit of the program was estimated for each risk-group separately.The overall incremental cost-effectiveness ratio of the program was €30,400/QALY gained, with effects and costs discounted at 1.5% and 4%, respectively. The program was more cost-effective in the first period (€24,200/QALY) than in the second period (€42,400/QALY). In particular, the cost-effectiveness for MSM decreased from €20,700/QALY to €47,700/QALY.This decentralised targeted HBV-vaccination program is a cost-effective intervention in certain unvaccinated high-risk adults. Saturation within the risk-groups, participation of individuals with less risky behaviour, and increased recruitment investments in the second period made the program less cost-effective over time. The project should therefore discus how to reduce costs per risk-group, increase effects or when to integrate the vaccination in regular healthcare.