Return on investment 2: evaluating the cost-effectiveness of needle and syringe programs in Australia 2009

Table B.1 Demographic, epidemiological and behavioural parameters

Page last updated: 2009

Table B.1 is separated into 4 smaller tables in this HTML version for accessibility reasons. It is presented as one table in the PDF version.

Demographic parameters
Epidemiology parameters
Behavioural parameters
Syringe cleaning parameters

Demographic parameters

Symbol Description Values References
N Population size of IDUs in Australia
173,500
(105,000-236,500)
[54, 132], a
N Population size of IDUs in the ACT, NSW, the NT, QLD, SA, TAS, VIC, WA or Indigenous
[54, 132], a
P Total number of syringes distributed per year

Epidemiology parameters

Symbol Description Values References
p0HIV Prevalence of HIV among IDUs in Australia
1.17% (0.90- 1.40%)
p0HIV Prevalence of HIV among IDUs in the ACT
0.12% (0.10- 1.10%)
p0HIV Prevalence of HIV among IDUs in NSW
1.49% (1.10- 2.00%)
p0HIV Prevalence of HIV among IDUs in the NT
0.72% (0.1 0- 1.10%)
p0HIV Prevalence of HIV among IDUs in QLD
1.64% (1.10- 2.00%)
p0HIV Prevalence of HIV among IDUs in SA
0.86% (0.50- 1.00%)
p0HIV Prevalence of HIV among IDUs in TAS
0.86% (0.10- 4.00%)
p0HIV Prevalence of HIV among IDUs in VIC
0.52% (0.40- 0.60%)
p0HIV Prevalence of HIV among IDUs in WA
0.43% (0.10- 0.80%)
p0HIV Prevalence of HIV among Indigenous IDUs
1.45% (1.10- 1.93%)
p0HCV Prevalence of HCV among IDUs
πAverage rate of people entering IDU population
1/ξ Average time of injecting drugs
8-17 years
[54, 133]
1/ξLAverage time it takes IDUs with liver-related disease to stop injecting
0.5-1 year
Experimental variable
Annual background death rate (not drug-related or disease-related)
0.5-0.7%
ω Percentage of syringes distributed that are not used
0.5-1%
Experimental variable
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Behavioural parameters

Symbol Description Values References
m Average size of a sharing group
2-2.5
Experimental variable
n Average number of injections per IDU per year (weighted average over all injecting frequency stratifications)
s Proportion of IDUs who share syringes
qProportion of injections that are shared for IDUs who share syringes in Australia
13-17%
qProportion of injections that are shared for IDUs who share syringes in ACT
10-14%
[54]
qProportion of injections that are shared for IDUs who share syringes in NSW
10-14%
[54]
qProportion of injections that are shared for IDUs who share syringes in NT
15-19%
[54]
qProportion of injections that are shared for IDUs who share syringes in Qld
11-14%
[54]
qProportion of injections that are shared for IDUs who share syringes in SA
12-16%
[54]
qProportion of injections that are shared for IDUs who share syringes in Tas
10-14%
[54]
qProportion of injections that are shared for IDUs who share syringes in Vic
13-17%
[54]
qProportion of injections that are shared for IDUs who share syringes in WA
16-20%
[54]
qProportion of injections that are shared for Indigenous IDUs who share syringes
15-25%
Experimental variable
δsAverage number of times each shared syringe is used before disposal
2.6-2.8
[54]
δpAverage number of times each non-shared syringe is used before disposal
2.1 (1.2-2.9)

Syringe cleaning parameters

Symbol Description Values References
pcsyringeProportion of syringes used by multiple people that are cleaned before re-use
5-10%
Experimental variable
pcotherProportion of times other equipment (spoons, tourniquets, etc) that is used by multiple people is cleaned before re-use
1-5%
Experimental variable
εcsyringe Effectiveness of syringe cleaning - HIV
60-75%
εcsyringe Effectiveness of syringe cleaning - HCV
25-35%
εcother Effectiveness of cleaning other equipment (spoons, tourniquets etc) - HIV
70-80%
Experimental variable
εcother Effectiveness of cleaning other equipment (spoons, tourniquets etc) - HCV
50-70%
Experimental variable
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