Injecting drug use in Australia: needle/syringe programs prove their worth, but hepatitis C still on the increase

In reply: Copeman's criticism of the report Return on investment in needle and syringe programs in Australia1 is essentially that the comparison of the effectiveness of needle/syringe programs (NSPs) is confounded by other factors. This point, and its implications for the results, was extensively discussed in that report. Copeman suggests that the estimated reduction in HIV due to NSPs might largely be attributable to the inclusion of data from many cities in Thailand that do not have NSPs. This criticism is not supported by the data. A sensitivity analysis including only cities from developed countries was performed at the time of the report (see Methods, Section 3.1.2, page 131), but was not included among the report's results because of space constraints and because it didn't alter the main findings. The analysis of cities in developed countries showed an overall mean reduction in the annual rate of change in HIV seroprevalence of –30.0%, compared with –24.7% based on all cities, albeit with lower statistical significance (P = 0.105 v P = 0.057), reflecting the loss in power through exclusion of cities.

Copeman's assertion that the report indicated that NSPs had no effect on rates of hepatitis C virus (HCV) infection is incorrect. The report estimated that, following the introduction of NSPs, HCV prevalence among injecting drug users declined by 2% per annum, compared with no introduction of NSPs (P < 0.001).

The report is freely available on the Internet,1 and we encourage readers to look at it for themselves.