Background: Our aim was to estimate the number of HIV infections that could have been prevented had needle-exchange programmes been implemented during the early stages of the AIDS epidemic in the USA. We also estimated the cost to the US health-care system to treat these preventable HIV infections.
Methods: The formula we used to calculate the annual number of preventable HIV infections accounted for the effectiveness and level of use of needle-exchange programmes, as well as sexual transmission to injection drug users (IDUs) and secondary transmission to their sexual partners and children. Data for the model were obtained from epidemiological and mathematical studies in peer-reviewed published research, government reports, and consultations with experts. Using data from Australia as a model, we calculated the number of HIV infections that could have been prevented by a national needle-exchange programme in the USA between 1987 and 1995. Cost calculations were based on the current US government estimate of the discounted lifetime cost of treating an HIV infection (US $55640).
Findings: Our conservative calculation of the number of HIV infections that could have been prevented ranged from 4394 (15% incidence reduction due to needle exchanges) to 9666 (33% incidence reduction). The cost to the US health-care system of treating these preventable HIV infections is between US $244 million and US $538 million, respectively. If current US policies are not changed, we estimate that an additional 5150-11329 preventable HIV infections could occur by the year 2000.
Interpretation: The failure of the federal government in the USA to implement a national needle-exchange programme, despite six government-funded reports in support of needle exchanges, may have led to HIV infection among thousands of IDUs, their sexual partners, and their children. Revoking the US government ban on funding for needle-exchange programmes and accelerating the growth of such programmes in the USA are urgent public-health priorities.