HIV incidence data are needed to prioritize resources for prevention and care. This information has not been easy to obtain using methods available in the past. Until recently, a handful of methods including back-calculation from AIDS case reports have been used to estimate HIV incidence. These methods have never provided a complete picture of the HIV epidemic; at most, they provide estimates for specific segments of the population or for people who voluntarily test for HIV. The development of the Serologic Testing Algorithm for Recent HIV Seroconversions (STARHS)1 provides a mechanism for estimating HIV incidence using cross-sectional data and blood specimen collection in a community.
The HIV/AIDS epidemic in Los Angeles is largely driven by infections among men who have sex with men (MSM)—one-third of new AIDS cases nationally are MSM2 compared to 61% in LAC.3 Recent HIV incidence estimates indicate that MSM in Los Angeles continue to have high rates of new HIV infection.4,5 While the proportion of AIDS cases attributed to injection drug use has been smaller in Los Angeles County than in the U.S. as a whole 2,3, injection drug users (IDUs) remain an important at-risk population. Furthermore, out-of-treatment IDUs recruited from some locations in LAC have historically demonstrated high HIV prevalence6, while little is known about HIV prevalence among out-of-treatment IDUs who live and congregate in other areas of LAC. Although very few studies have attempted to determine HIV incidence among high-risk heterosexuals (HRH), an increase in the proportion of AIDS cases in LAC identified as HRH has been detected (from 4.4% of AIDS cases in 1992 to 8.1% of AIDS cases in 1999).3 While it has long been clear that information on incident infections is important, it has only recently, with the availability of STARHS testing, become feasible to estimate HIV incidence using cross-sectional study designs.
By targeting research efforts on those individuals who are newly diagnosed, relevant information concerning changing behaviors and attitudes can be evaluated. In addition, the referral patterns of those recently diagnosed can be evaluated to determine if prevention services, HIV-related health care, and social support services are being accessed appropriately. By evaluating how new infections are occurring, who is becoming infected, and whether newly infected persons are receiving referrals and appropriate services, we will be able to obtain crucial scientific information for resource prioritization in Los Angeles County.
Project One addresses these gaps in information by integrating two main study components in selected geographic areas (Chicago, Dallas, and Los Angeles). The main components are: 1) estimating HIV incidence in at-risk populations in the Los Angeles County jails and in "Skid Row" single resident occupancy (SRO) hotels among IDUs, MSM, and HRHs; and 2) in the "Behavioral and Viral Characterization Study," the objective is to identify and describe the socio-demographic, behavioral and viral characteristics of recently infected and newly diagnosed individuals. Those found to be recently infected are subsequently referred to the "Context of HIV Infection Project".
The first component of Project One consists of two cross-sectional HIV incidence surveys using STARHS methodology in the following study populations: 1) new arrestees at the Twin Towers Jails and the Men’s Central jail and; 2) residents of low-income hotels in the skid row area of downtown Los Angeles. HIV prevalence will be determined in the course of estimating HIV incidence. General eligibility requirements for these surveys include: residence in SPA 4 (Metro) or SPA 6 (South); age 18 to 65 years: speak English or Spanish; and have no previous HIV diagnosis. Only individuals reporting injection drug use, men with a history of sex with other men, and men and women reporting recent "high-risk" heterosexual activity will be included in the incidence and prevalence estimates obtained in these studies.
The second component, "Behavioral and Viral Characterization", is a cross-sectional study of persons with recent or newly diagnosed HIV infection. Potential research subjects are identified and recruited through (1) HIV incidence studies, (2) a network of HIV health care providers, and (3) partner notification services. HIV Epidemiology Program staff and collaborators engaged in the incidence studies, provider network, and partner notification services will refer each eligible client encountered in the field to the Behavioral and Viral Characterization Study project coordinator who will schedule the initial research encounter. During this encounter, consenting participants will undergo phlebotomy and a structured quantitative interview on socio-demographic characteristics, HIV risk behaviors, and utilization of HIV health care and prevention services. CD4 counts, HIV genotype and phenotype and HIV viral load tests will be performed on the blood samples collected at the initial research encounter. In the absence of a previously drawn blood sample (i.e., from the HIV incidence studies), STARHS test will be offered at the initial research encounter. For any participant who did not consent to STARHS testing during the incidence studies will be offered STARHS testing again. Following the quantitative behavioral assessment, participants will be provided with additional prevention counseling to reduce their risks for transmitting HIV, referrals for HIV medical and social services, and partner notification services.
Trista Bingham, Principal Investigator, 213-351-8175.
- Janssen RS; Satten GA; Stramer SL; Rawal BD; O'Brien TR; Weiblen BJ; Hecht FM; Jack N; Cleghorn FR; Kahn JO; Chesney MA; Busch MP. New Testing Strategy to Detect Early HIV-1 Infection for Use in Incidence Estimates and for Clinical and Prevention Purposes. JAMA 1998;280(1):42-48.
- Centers for Disease Control and Prevention. HIV/AIDS Surveillance Report, 2000; 12 (No. 2):1-18.
- HIV Epidemiology Program, Los Angeles County Department of Health Services. Advanced HIV Disease (AIDS) Surveillance Summary, July 15, 2001:1-26.
- Centers for Disease Control and Prevention. HIV Incidence Among Young Men Who Have Sex With Men – Seven U.S. Cities, 1994-2000. MMWR 2001; 50:440-4.
- Bingham T, Harawa N, Johnson D, Kerndt P. HIV Incidence Rates in Los Angeles County Sexually Transmitted Disease (STD) Clinics Using the Strategic Testing Algorithm for Recent HIV Seroconversion (STARHS) Method. Universitywide AIDS Research Program (UARP), 3rd Annual Conference on AIDS Research in California. San Francisco, CA. February 25, 2000.
- Lopez-Zetina J, Woehrle T, Ford W, Weber M, Kerndt P. Viral Infections and History of Institutionalization Among Young and Recent Initiates to Injection Drug Use in Los Angeles County, 1997-1998. UARP 2nd Annual Conference on AIDS Research in California. San Diego, CA. February 26, 1999.