A systematic review including 214 studies was abstracted in DARE. 81 cities had both HIV seroprevalence figures for more than 1 year and information on needle exchange programme (NEP) implementation.
In cities with NEPs, HIV seroprevalence among injecting drug users decreased by 5.8% on average, whereas in cities without NEPs, HIV seroprevalence increased by 5.9%. The average annual change in seroprevalence was 11% lower in cities with NEPs (95% CI -17.6% to -3.9%, p=0.004).