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HIV Epidemiology


HIV Epidemiology

Contact Information
Los Angeles County
Department of Public Health
HIV Epidemiology, DHSP                       600 S. Commonwealth Ave. Suite 1920
Los Angeles, CA 90005
Phone: (213) 351-8196
Fax: (213) 487-9386


        LAC's ZIP code level data/maps on HIV

HIV Epidemiology - Collaborative Intravenous Drug Users Study, CIDUS II Young and Recent Initiates to Injecting Drug Use

Approximately one-third of all reported AIDS cases in the U.S. are related either directly or indirectly to injection drug use. Los Angeles County has an estimated 120,000-190,000 injection drug users (IDUs), the second-largest drug-injecting population in the United States. The more that is known about the risk behaviors of IDUs in this area, the better agencies might be able to tailor HIV prevention messages to reach IDUs.

The Collaborative Intravenous Drug Users Study, CIDUS II, will look at HIV risk behaviors of injection drug users (IDUs) between the ages of 15-29 who began shooting drugs within the last three years. Study participants will be interviewed and tested for HIV, hepatitis B and C, and urine will be collected for LCR testing for gonorrhea and chlamydia every six months for a period of a year and a half.


  1. To estimate incidence and prevalence of HIV, hepatitis B and C, gonorrhea, and chlamydia among new IDUs.
  2. To learn about risk behaviors of new IDUs within their social networks (that is, with their injecting and sexual partners).
  3. To evaluate differences in the characteristics of social networks of new and long-term IDUs and how those differences might affect their chances of getting HIV.

Study Design:

One of the objectives of this study is to learn whether the risk of getting HIV is higher for people who are just starting to inject drugs compared to long-term injectors, as some studies have shown. Another is to determine how the social networks of IDUs impact their risk behaviors as well as their chances of getting HIV, since studies have shown a link between these factors. The study objectives can be accomplished through prospective observation and testing of eligible participants enrolled at baseline. The longitudinal design of the study will allow researchers at the HIV Epidemiology Program to estimate incidence rates of HIV infection, Hepatitis B and C, gonorrhea and chlamydia in a population of high risk individuals who are typically hard to reach and to study. Participants are recruited at two street locations with a substantial concentration of injection drug users: Hollywood and Long Beach. Subjects in the selected neighborhoods are recruited with an intercept protocol based on a semistructured screening interview to determine eligibility. Peer and/or indigenous outreach workers trained in survey administration and certified in HIV counseling and phlebotomy conduct outreach at these locations in a mobile testing unit especially equipped for collecting blood specimens and conducting private, confidential interviews. At six-month intervals after the baseline interview, participants are actively followed with repeated risk behavior interviews and serologic screening.

Contact Persons:

Theresa Woehrle, M.D., M.P.H.
Principal Investigator

Javier L. Zetina, Ph.D.

David Norton, Ph.D.
Project Coordinator

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