no direct evidence that SIS influence rates of other infections. It is not known if the health needs of INSITE users' change over time. Impact on Overdose Fatalities The evidence from table A5 supports the following conclusions: Conclusions INSITE staff have successfully intervened in over 336 overdose events since 2006 and no overdose deaths have occurred at the service. Mathematical modelling (see caution about validity below) suggests that INSITE saves about one life a year as a result of intervening in overdose events. Limitations of research There is no direct evidence that SIS influence overdose death rates and large scale and long-term, case-controlled studies 8 would be needed to show that SISs influence overdose death rates among those who use INSITE. Mathematical modelling is based on assumptions that may not be valid. Reducing the Transmission of Blood-Borne Viral Infections Like HIV and HCV and Other Injection-Related Infections The evidence from table A6 supports the following conclusions: Conclusions Self-reports from users of the INSITE service and from users of SIS services in other countries indicate that needle sharing decreases with increased use of SISs . Mathematical Modeling, based on assumptions about baseline rates of needle sharing, the risks of HIV transmission and other variables, generated very wide ranging estimates for the number of HIV cases that might have been prevented. The EAC were not convinced that these assumptions were entirely valid. Limitations of research There is no direct evidence that SISs reduce rates of HIV infection, and the mathematical models used