HIV incidence among injection drug users enrolled in a Los Angeles methadone program

Methadone induces CCR5 and promotes AIDS virus infection

Methadone, a regimen for the treatment of opioid dependency, was found to induce the expression of CCR5, a co-receptor for human immunodeficiency virus (HIV)/simian form of HIV (SIV) entry, on human CEM x174 lymphocytes. Both CCR5 mRNA and protein were elevated in methadone-treated cells. A concomitant increase of mu opioid receptors was also observed. Upon methadone exposure, SIVmac239-infected CEM x174 cells released greater amounts of virus particles as revealed by both the number of syncytia formation and reverse transcriptase activities. Similar methadone effect was not observed on CEM x174 cells infected with other simian retroviruses that do not depend on CCR5 for cellular entry. These studies raise concerns considering methadone as an innocuous morphine substitute.

HIV in the United States at the turn of the century: an epidemic in transition

OBJECTIVES

The current status of and changes in the HIV epidemic in the United States are described.

METHODS

Surveillance data were used to evaluate time trends in AIDS diagnoses and deaths. Estimates of HIV incidence were derived from studies done during the 1990s; time trends in recent HIV incidence were inferred from HIV diagnoses and seroprevalence rates among young persons.

RESULTS

Numbers of deaths and AIDS diagnoses decreased dramatically during 1996 and 1997 but stabilized or declined only slightly during 1998 and 1999. Proportional decreases were smallest among African American women, women in the South, and persons infected through heterosexual contact, HIV incidence has been roughly constant since 1992 in most populations with time trend data, remains highest among men who have sex with men and injection drug users, and typically is higher among African Americans than other racial/ethnic groups.

CONCLUSIONS

The epidemic increasingly affects women minorities, persons infected through heterosexual contact, and the poor. Renewed interest and investment in HIV and AIDS surveillance and surveillance of behaviors associated with HIV transmission are essential to direct resources for prevention to populations with greatest need and to evaluate intervention programs.

Incidence of HIV among injection drug users entering drug treatment programs in four US cities

We estimated seroincidence of human immunodeficiency virus (HIV) and prevalence of risk behaviors among injection drug users (IDUs) who accepted voluntary HIV testing on entry to drug treatment. Record-based incidence studies were conducted in 12 drug treatment programs in New York City (n = 890); Newark, New Jersey (n = 521); Seattle, Washington (n = 1,256); and Los Angeles, California (n = 733). Records of confidential HIV tests were abstracted for information on demographics, drug use, and HIV test results. More detailed data on risk behaviors were obtained by a standardized questionnaire. Although overall incidence rates were relatively low in this population (<1/100 person-years), there was a high prevalence of risk behaviors. Needle sharing was reported by more than one-third of the participants in each of the cities. HIV seroincidence rates were up to three-fold higher among younger ID Us. We found that HIV continued to be transmitted among ID Us who had received both drug treatment and HIV counseling and testing. HIV/AIDS (acquired immunodeficiency syndrome) prevention education should continue to be an important component of drug treatment.

Predictors of syphilis seroreactivity and prevalence of HIV among street recruited injection drug users in Los Angeles County, 1994-6

OBJECTIVES

To describe HIV prevalence and the association between syphilis incidence and sexual and drug injection risk behaviours in a cohort of street recruited injecting drug users (IDUs) in Los Angeles County, between 1994 and 1996.

METHODS

During the study period, 513 street recruited African-American and Latino IDUs were screened for syphilis and antibodies to HIV. Subjects were administered a risk behaviour survey at baseline and followed up at 6 month intervals for 18 months with repeated interviews and serological screening. Rate ratios were used to examine associations between syphilis incidence and demographic characteristics and risk behaviours. A proportional hazard model was used to identify predictors of syphilis incidence independent of demographic characteristics.

RESULTS

74% of the sample were male, 70% African-American, 30% Latino; and the median age was 43 years. Overall baseline serological prevalence of HIV was 2.5% and of syphilis 5.7%. None of the participants were co-infected for HIV and syphilis at baseline or at any of the 6 month follow ups. Among 390 eligible IDUs retained for analysis of incidence data, the overall syphilis incidence was 26.0 per 1000 person years. Higher syphilis incidence was found for women compared with men (RR = 2.70; 95% CI 1.60, 4.55), and for those 44 years of age or younger compared with those 45 years of age and older (RR = 2.26; 95% CI 1.25, 4.08). African-Americans were more likely to be syphilis incident cases when compared with Latinos, although the difference did not reach statistical significance (RR = 1.27; 95% CI 0.72, 2.23). In bivariate analysis, risk behaviours significantly associated with higher syphilis incidence included injection of cocaine, "speedball" and heroin, "crack" smoking, recency of first injection event, backloading of syringes, injecting with others, exchanging drugs or money for sex, multiple sex partners, and non-heterosexual sexual preference. Variables that significantly predicted syphilis infection at follow up in the multivariate analysis included multiple sex partners (RR = 7.8; 95% CI 2.4, 25.0), exchanging money for sex (RR = 3.0; 95% CI 0.9, 9.6), and recent initiation to injection drug use (RR = 4.6; 95% CI 1.1, 18.8).

CONCLUSION

Syphilis transmission among IDUs in Los Angeles County remains a serious public health concern, particularly among IDUs who engage in trading of sex for money or drugs. Although low, the prevalence of HIV observed in this study constitutes a serious concern because of the potential for expanded HIV transmission in this susceptible population of IDUs with high syphilis incidence. Enhanced case finding screening efforts and prevention of transmission of sexually transmitted infections should specifically target hard to reach IDUs and their sexual partners.