dcyphr | HIV Incidence Among Injection Drug Users in New York City, 1990 to 2002: Use of Serologic Test Algorithm to Assess Expansion of HIV Prevention Services


3651 injection drug users (IDUs) were tested for HIV using Serologic Test Algorithm for Recent HIV Seroconversion (STARHS). The HIV incidence in IDUs decreased from 3.55 per 100 people to 0.77 per 100 people from 1990 to 2002. During this time, syringe exchange programs increased in use for 250,000 to 3,000,000 syringes exchanged per year. There is a clear association between syringe exchange programs and HIV prevalence.


This study aims to see if syringe exchange programs decreased the prevalence of HIV in injection drug users from 1990 to 2002.


It is difficult to collect valid HIV incidence data overtime, so the new system called Serologic Test Algorithm for Recent HIV Seroconversion (STARHS) is used. STARHS can be used to predict HIV incidence over time by using two different testing methods. One is very sensitive to HIV antibodies, so it can tell us if someone has had HIV for a long time since their body would have had time to make antibodies. The other is not very sensitive to HIV antibodies, so it can tell us if the infection is new and the person’s immune system has not had enough time to make the antibodies yet. This study looks at HIV testing beginning when New York City started rapidly expanding their HIV prevention programs, which included needle exchange programs, HIV testing services, and other support services.


The incidence of HIV from 1990-1992 was 3.55 per 100 people. The incidence of HIV from 1993-1995 was 2.63 per 100 people; from 1996-1998 was 1.05 per 100 people; and from 1999-2002 was .77 per people. Each year, the amount of needles exchanged was increased starting at 250,000 in and ending at 3,000,000 needles exchanged per year.


Limitations and Strength of STARHS

The limitations are the small sample size, as well as the ability for STARHS to give false positive and negative results. The strengths are the ability of STARHS to be able to determine new and old infections, and the fact that the data in this study lined up with other short term studies done to assess the incidence of new HIV infections.

Effectiveness of Syringe Exchange in New York City, 1990-2002

Along with the several studies done to promote needle exchange programs, this study also suggests that needle exchange programs in combination with other resources can decrease the incidence of HIV. Though the needle exchange programs were important, it should be noted that the needle exchange programs were not the only factor to reduce HIV incidence. Other outreach programs and services contributed to the decrease in new infections.

Implications for Future Research

STARHS should be used for other studies wanting to look at incidence of diseases, but should be monitored for the possibility of false results.

Implications for Public Health

Areas with high levels of HIV infections should attempt to collaborate between the state officials, healthcare workers, and community services to include needle exchange programs.


The patients included in this study had reported using injection drugs within the past 6 months. False positive STARHS HIV tests were accounted for in this study. One period (1990-1992) included data before the needle exchange program was put into place. The other periods were all years following the start of the needle exchange program.


HIV incidence decreased with the expansion of needle exchange programs and other HIV prevention services.