Key findings
- The median age of participants was relatively stable at between 27 and 29 years during the first half of the survey period, but increased in subsequent years. Median age increased from a low of 27 years in 1997 to 37 years in 2010, with a concurrent decline in the proportion of respondents aged younger than 25 years, from 36% in 1997 to 8% in 2010.
- HIV antibody prevalence remained low at 2.1% or less in all of the past sixteen years, with prevalence of 1.0% observed in 2010.
- HIV prevalence was highest among participants reporting male homosexual identity, who comprised between 2% and 5% of annual survey samples, with prevalence in this group ranging from 14% to 39%.
- While there were shifts in the patterns of drugs injected as reported by ANSPS participants over the past 16 years, reports of heroin and methamphetamine as the drugs last injected remained prominent in all survey years.
- The proportion of participants who reported last injecting pharmaceutical opioids remained stable at 3% to 4% during the 1990s. However, prevalence has increased recently, with 16% of participants in 2010 reporting last injecting this class of drug.