The epidemiological transmission model for HIV and HCV was applied to IDUs and NSPs specifically in Tasmania. The model was used to evaluate current NSPs versus no program and to project likely epidemiological impacts of potential changes to the program. The model estimated the expected number of HIV and HCV cases in Tasmania with and without NSP distribution of sterile injecting equipment (Figure 50). The estimated number of infections averted is presented in Figure 51. Less than one HIV infection would be expected due to syringe sharing by IDUs, on average, in Tasmania even without NSPs. Thus, NSPs are currently not preventing HIV infections in Tasmania. However, NSPs are very effective in averting HCV transmissions. It is estimated that over the last ten years they have averted 2,530 (2,404-2,677, IQR) new HCV infections.

Figure 50: Estimated HIV and HCV incidence in Tasmania with and without NSPs

Text equivalent below for Figure 50: Estimated HIV incidence in Tasmania with NSPsText equivalent below for Figure 50: Estimated HIV incidence in Tasmania without NSPsText equivalent below for Figure 50: Estimated HCV incidence in Tasmania with NSPsText equivalent below for Figure 50: Estimated HCV incidence in Tasmania without NSPs

Text version of Figure 50

Top of pageFigures in this description are approximate as they have been read from the graph.

Figure 50 consists of four graphs:
  • Estimated HIV incidence in Tasmania with NSPs

    • The 100 model simulations decrease gradually from a range of 0-0.005 in 1999 to 0-0.004 in 2009.

    • The median of the model simulations does not appear until 2000 and remains at 0.001 to 2009.

    • The lower quartile of the model simulations is not visible.

    • The upper quartile of the model simulations is not visible.

    • The notification data for annual incidence of HIV in Tasmania is less than 0.01 for all years between 1999 and 2007.

  • Projected annual HIV incidence in Tasmania without NSPs

    • The 100 model simulations increase dramatically from a range of 0-0.005 in 2009 to 0-0.04 in 2000 and increase to 0-0.062 by 2020.

    • The median of the model simulations increases slightly from 0.0005 in 2009 to 0.001 in 2020.

    • The lower quartile of the model simulations is not visible.

    • The upper quartile of the model simulations is not visible.

    • The notification data for annual incidence of HIV in Tasmania is less than 0.01 for all years between 1999 and 2007.

  • Estimated HCV incidence in Tasmania with NSPs

    • The 100 model simulations decrease slightly from a range of 170-180 in 1999 to 130-140 in 2001 before decreasing gradually to 120-130 in 2004 and remain constant to 2009.

    • The median of the model simulations decreases slightly from 175 in 1999 to 135 in 2001, decreases gradually to 120 in 2004 and remains constant to 2009.

    • The lower quartile of the model simulations is not visible.

    • The upper quartile of the model simulations is not visible.

    • The notification data for annual incidence of HCV in Tasmania is:
      • 1999 - 170
      • 2000 - 175
      • 2001 - 140
      • 2002 - 125
      • 2003 - 120
      • 2004 - 115 Top of page
      • 2005 - 115

  • Estimated HCV incidence in Tasmania without NSPs

    • The 100 model simulations increase sharply from a range of 180-200 in 1998 to 590-680 in 1999, widens to 680-860 in 2000 and decrease rapidly to 240-400 by 2002. The model simulations then decrease gradually to 210-300 by 2009.

    • The median of the model simulations increases sharply from 190 in 1998 to 630 in 1999, increases sharply to 780 in 2000 and decreases rapidly to 320 in 2008. The median then increases slightly to 250 in 2009.

    • The lower quartile of the model simulations increases sharply from 180 in 1998 to 610 in 1999, increases sharply to 720 in 2000 and decreases rapidly to 300 in 2008. The lower quartile then increases slightly to 240 in 2009.

    • The upper quartile of the model simulations increases sharply from 200 in 1998 to 660 in 1999, increases sharply to 800 in 2000 and decreases rapidly to 350 in 2008. The upper quartile then increases slightly to 260 in 2009.

    • The notification data for annual incidence of HCV in Tasmania is:
      • 1999 - 170
      • 2000 - 175
      • 2001 - 140
      • 2002 - 125
      • 2003 - 120
      • 2004 - 115
      • 2005 - 115

Figure 51: Estimated cumulative number of HIV and HCV cases averted in Tasmania due to NSPs

Text equivalent below for Figure 51: Estimated cumulative number of HIV cases averted in Tasmania due to NSPsText equivalent below for Figure 51: Estimated cumulative number of HCV cases averted in Tasmania due to NSPs

Text version of Figure 51

Top of pageFigures in this description are approximate as they have been read from the graph.

Figure 51 consists of two graphs:
  • Expected cumulative number of HIV cases averted in Tasmania due to NSPs

    • With NSPs (current coverage) the cumulative number of HIV cases in Tasmania increases gradually from 0.0001 in 1998 to 0.0005 in 2009.

    • Without NSPs the cumulative number of HIV cases in Tasmania increases gradually from almost 0 in 1998 to 0.0042 in 2009.

  • Expected cumulative number of HCV cases averted in Tasmania due to NSPs

    • With NSPs (current coverage) the cumulative number of HCV cases in Tasmania increase gradually from below 100 in 1999 to 1,400 in 2009.

    • Without NSPs the cumulative number of HCV cases in Tasmania increases sharply from 600 in 1999 to 1,400 in 2000, and increases gradually to 3,900 by 2009.