| Behavioural parameters by main source of syringes (model scenarios for which data are used are given brackets) | Variable used in Table A1 | Main source of needles/syringes is either pharmacy, shop, hospital, health worker (i = 0) | Main source of needles/syringes is either found, IDU, drug dealer, friend, etc (i = 1) | |
| Percentage of IDUs reporting their main source of syringes as [s1–4] | Ai | 80.4% (75.4% to 84.8%) | Remainder | |
| Frequency of injecting per month [s1,2] | Bi | 51.9 (48.1 to 55.7) | 93.3 (28.2 to 158.3) | |
| Percentage of IDUs that ever share syringes [s1–4] | Ci | 28.2% (22.5% to 34.3%) | 89.7% (78.8% to 96.1%) | |
| For those that share: | ||||
| Percentage of injections shared [s1,2] | Di | 31.3% (20.9% to 39.9%) | 64.4% (49.3% to 72.4%) | |
| Average number of IDUs share with per week [s1–4] | Ei | 1.8 (1.5 to 2.1) | 3.9 (3.2 to 4.6) | |
| Proportion of IDUs that they shared with that they had not shared with before (“stranger”) [s2–4] | Fi | 5.1% (1.6% to 8.6%) | 24.1% (16.5% to 31.8%) | |
| Percentage of IDUs that ever share syringes [s5] | G | 41.1% (35.4% to 46.8%) | ||
| Percentage that reported sharing with “stranger” in last week [s5] | H | 9.4% (6.3% to 13.3%) | ||
| Of these, the number of “strangers” that they shared with per month [s5] | I | 7.3 (5.6 to 10.0) | ||
| Proportion of IDUs who cleaned their syringe the last time they shared [s1–5] | 79.3% (73.1% to 84.7%) | |||
| Duration IDUs inject drugs [s1–5] | 4–8 years (mean duration of current IDUs is 6 years) | |||
| Degree of like-with-like mixing between IDUs with different levels of syringe sharing or durations of injecting [s1–5] | 0–0.5 for both (no data) | |||
IDU, intravenous drug user.
Ranges in brackets are 95% confidence intervals and all data are from the survey unless otherwise stated.