Hepatitis B vaccine uptake among injecting drug users in England 1998 to 2004: is the prison vaccination programme driving recent improvements?

In 1999, the Department of Health allocated additional funding to Health Authorities in England to expand hepatitis B immunization among injecting drug users (IDUs), with the aim of increasing coverage by 20%. In 2001, a vaccination programme for prison inmates in England was also instigated. Between 1998 and 2004 current IDUs participated in a series of annual unlinked anonymous surveys that recorded vaccine uptake (n = 11 383). The proportion self-reporting vaccine uptake rose significantly from 27% in 1998 to 59% in 2004 [adjusted odds ratio: 3.7 (95% CI 3.2-4.3); increase in uptake of 25% per annum (95% CI 22-27%)]. A second survey, which recruited 852 current IDUs from community settings in 2003/04, found that prisons were the most common source (38%) of vaccine doses, followed by drug services (28%) and general practitioners (17%), with only 14% receiving doses through needle exchanges. These data suggest that the 20% target of improving vaccination coverage has been met, with the prison vaccination programme likely to have made a substantive contribution in recent years. However, prevalence of antibodies to the hepatitis B core antigen was stable (21%) and is currently similar among the vaccinated and unvaccinated. Consideration needs to be given to improving community vaccination provision for IDUs, targeting recent initiates, and determining when surveillance data should indicate reductions in infection so that the effectiveness of the targeted strategy can be assessed.