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

Incidence of HIV and hepatitis C virus among people who inject drugs, and associations with age and sex or gender: a global systematic review and meta-analysis

BACKGROUND

Measuring the incidence of HIV and hepatitis C virus (HCV) infection among people who inject drugs (PWID) is key to track progress towards elimination. We aimed to summarise global data on HIV and primary HCV incidence among PWID and associations with age and sex or gender.

METHODS

In this systematic review and meta-analysis, we updated an existing database of HIV and HCV incidence studies among PWID by searching MEDLINE, Embase, and PsycINFO, capturing studies published between Jan 1, 2000, and Dec 12, 2022, with no language or study design restrictions. We contacted authors of identified studies for unpublished or updated data. We included studies that estimated incidence by longitudinally re-testing people at risk of infection or by using assays for recent infection. We pooled incidence and relative risk (RR; young [generally defined as ≤25 years] vs older PWID; women vs men) estimates using random-effects meta-analysis and assessed risk of bias with a modified Newcastle-Ottawa scale. This study is registered with PROSPERO, CRD42020220884.

FINDINGS

Our updated search identified 9493 publications, of which 211 were eligible for full-text review. An additional 377 full-text records from our existing database and five records identified through cross-referencing were assessed. Including 28 unpublished records, 125 records met the inclusion criteria. We identified 64 estimates of HIV incidence (30 from high-income countries [HICs] and 34 from low-income or middle-income countries [LMICs]) and 66 estimates of HCV incidence (52 from HICs and 14 from LMICs). 41 (64%) of 64 HIV and 42 (64%) of 66 HCV estimates were from single cities rather than being multi-city or nationwide. Estimates were measured over 1987-2021 for HIV and 1992-2021 for HCV. Pooled HIV incidence was 1·7 per 100 person-years (95% CI 1·3-2·3; I2=98·4%) and pooled HCV incidence was 12·1 per 100 person-years (10·0-14·6; I2=97·2%). Young PWID had a greater risk of HIV (RR 1·5, 95% CI 1·2-1·8; I2=66·9%) and HCV (1·5, 1·3-1·8; I2=70·6%) acquisition than older PWID. Women had a greater risk of HIV (RR 1·4, 95% CI 1·1-1·6; I2=55·3%) and HCV (1·2, 1·1-1·3; I2=43·3%) acquisition than men. For both HIV and HCV, the median risk-of-bias score was 6 (IQR 6-7), indicating moderate risk.

INTERPRETATION

Although sparse, available HIV and HCV incidence estimates offer insights into global levels of HIV and HCV transmission among PWID. Intensified efforts are needed to keep track of the HIV and HCV epidemics among PWID and to expand access to age-appropriate and gender-appropriate prevention services that serve young PWID and women who inject drugs.

FUNDING

Canadian Institutes of Health Research, Fonds de recherche du Québec-Santé, Canadian Network on Hepatitis C, UK National Institute for Health and Care Research, and WHO.

Modeling HIV transmission among persons who inject drugs (PWID) at the "End of the HIV Epidemic" and during the COVID-19 pandemic

BACKGROUND

We explore injecting risk and HIV incidence among PWID in New York City (NYC), from 2012 to 2019, when incidence was extremely low, <0.1/100 person-years at risk, and during disruption of prevention services due to the COVID-19 pandemic.

METHODS

We developed an Agent-Based model (ABM) to simulate sharing injecting equipment and measure HIV incidence in NYC. The model was adapted from a previous ABM model developed to compare HIV transmission with "high" versus "low" dead space syringes. Data for applying the model to NYC during the period of very low HIV incidence was taken from the "Risk Factors" study, a long-running study of participants entering substance use treatment in NYC. Injecting risk behavior had not been eliminated in this population, with approximately 15 % reported recent syringe sharing. Data for possible transmission during COVID-19 disruption was taken from previous HIV outbreaks and early studies of the pandemic in NYC.

RESULTS

The modeled incidence rates fell within the 95 % confidence bounds of all of the empirically observed incidence rates, without any additional calibration of the model. Potential COVID-19 disruptions increased the probability of an outbreak from 0.03 to 0.25.

CONCLUSIONS

The primary factors in the very low HIV incidence were the extremely small numbers of PWID likely to transmit HIV and that most sharing occurs within small, relatively stable, mostly seroconcordant groups. Containing an HIV outbreak among PWID during a continuing pandemic would be quite difficult. Pre-pandemic levels of HIV prevention services should be restored as quickly as feasible.

Geographic distribution of risk ("Hotspots") for HIV, HCV, and drug overdose among persons who use drugs in New York City: the importance of local history

AIMS

To identify geographic "hotspots" for potential transmission of HIV and HCV and for drug overdose among persons who use heroin and cocaine in New York City and to examine historical continuities in problem drug use hotspots in the city.

METHODS

A total of 2714 study participants were recruited among persons entering Beth Israel substance use treatment programs. A structured questionnaire was administered and blood samples for HIV and HCV testing were collected. Hotspots for potential virus transmission were defined as ZIP codes with 10+ participants, 2+ persons infected with the virus and engaging in transmission behavior, and 2+ persons not infected and engaging in acquisition behavior. ZIP codes with 3+ persons with previous overdoses were considered potential hotspots for future overdoses.

RESULTS

Participants resided in 166/178 (93%) of the ZIP codes in New York City. Injecting drug use was reported in 150/178 (84%) of the ZIP codes. No zip codes were identified for injecting-related HIV transmission, 5 zip codes were identified for sexual HIV transmission, 3 for HCV transmission, and 8 for drug overdose. Many of the ZIP code potential hotspots were in neighborhoods long associated with drug use: Lower Eastside and Harlem in Manhattan, the South Bronx, and Central Brooklyn.

DISCUSSION

Heroin and cocaine use requiring treatment were reported from almost all ZIP codes in New York City, indicating needs for widely dispersed harm reduction services. Identified hotspots should be targeted for reducing sexual transmission of HIV, transmission of HCV, and drug overdoses. Some of the hotspots have persisted as problem drug use areas for 40 to over 100 years. Monitoring of drug use patterns in historical hotspot neighborhoods may permit early identification of and response to emerging drug use-related health problems. Persistent historical hotspots for problem drug use present a complex problem for implementing harm reduction services that deserve additional research.

Hepatitis C virus prevalence and estimated incidence among new injectors during the opioid epidemic in New York City, 2000-2017: Protective effects of non-injecting drug use

OBJECTIVE

Assess hepatitis C virus (HCV) prevalence and incidence among person who began injecting drugs during the opioid epidemic in New York City (NYC) and identify possible new directions for reducing HCV infection among persons who inject drugs.

METHODS

846 persons who began injecting drugs between 2000 and 2017 were recruited from persons entering Mount Sinai Beth Israel substance use treatment programs. A structured interview was administered and HCV antibody testing conducted. Protective effects of non-injecting drug use were examined among persons who "reversed transitioned" to non-injecting drug use and persons who used non-injected heroin in addition to injecting.

RESULTS

Participants were 79% male, 41% White, 15% African-American, 40% Latinx, with a mean age of 35. Of those who began injecting in 2000 or later, 97 persons (11%) "reverse transitioned" back to non-injecting drug use. Reverse transitioning was strongly associated with lower HCV seroprevalence (30% versus 47% among those who continued injecting, p < 0.005). Among those who continued injecting, HCV seropositivity was inversely associated with current non-injecting heroin use (AOR = 0.72, 95%CI 0.52-0.99). HCV incidence among persons continuing to inject was estimated as 13/100 person-years. HCV seropositive persons currently injecting cocaine were particularly likely to report behavior likely to transmit HCV.

CONCLUSIONS

Similar to other locations in the US, NYC is experiencing high rates of HCV infection among persons who have begun injecting since 2000. New interventions that facilitate substitution of non-injecting for injecting drug use and that reduce transmission behavior among HCV seropositives may provide additional methods for reducing HCV transmission.

Potential geographic "hotspots" for drug-injection related transmission of HIV and HCV and for initiation into injecting drug use in New York City, 2011-2015, with implications for the current opioid epidemic in the US

OBJECTIVE

We identified potential geographic "hotspots" for drug-injecting transmission of HIV and hepatitis C virus (HCV) among persons who inject drugs (PWID) in New York City. The HIV epidemic among PWID is currently in an "end of the epidemic" stage, while HCV is in a continuing, high prevalence (> 50%) stage.

METHODS

We recruited 910 PWID entering Mount Sinai Beth Israel substance use treatment programs from 2011-2015. Structured interviews and HIV/ HCV testing were conducted. Residential ZIP codes were used as geographic units of analysis. Potential "hotspots" for HIV and HCV transmission were defined as 1) having relatively large numbers of PWID 2) having 2 or more HIV (or HCV) seropositive PWID reporting transmission risk-passing on used syringes to others, and 3) having 2 or more HIV (or HCV) seronegative PWID reporting acquisition risk-injecting with previously used needles/syringes. Hotspots for injecting drug use initiation were defined as ZIP codes with 5 or more persons who began injecting within the previous 6 years.

RESULTS

Among PWID, 96% injected heroin, 81% male, 34% White, 15% African-American, 47% Latinx, mean age 40 (SD = 10), 7% HIV seropositive, 62% HCV seropositive. Participants resided in 234 ZIP codes. No ZIP codes were identified as potential hotspots due to small numbers of HIV seropositive PWID reporting transmission risk. Four ZIP codes were identified as potential hotspots for HCV transmission. 12 ZIP codes identified as hotspots for injecting drug use initiation.

DISCUSSION

For HIV, the lack of potential hotspots is further validation of widespread effectiveness of efforts to reduce injecting-related HIV transmission. Injecting-related HIV transmission is likely to be a rare, random event. HCV prevention efforts should include focus on potential hotspots for transmission and on hotspots for initiation into injecting drug use. We consider application of methods for the current opioid epidemic in the US.

HIV-associated cellular senescence: A contributor to accelerated aging

Due to the advent of antiretroviral therapy HIV is no longer a terminal disease and the HIV infected patients are becoming increasingly older. While this is a major success, with increasing age comes an increased risk for disease. The age-related comorbidities that HIV infected patients experience suggest that they suffer from accelerated aging. One possible contributor to this accelerated aging is cellular senescence, an age-associated response that can occur prematurely in response to stress, and that is emerging as a contributor to disease and aging. HIV patients experience several stressors such as the virus itself, antiretroviral drugs and to a lesser extent, substance abuse that can induce cellular senescence. This review summarizes the current knowledge of senescence induction in response to these stressors and their relation to the comorbidities in HIV patients. Cellular senescence may be a possible therapeutic target for these comorbidities.

Basic science and pathogenesis of ageing with HIV: potential mechanisms and biomarkers

: The increased prevalence of age-related comorbidities and mortality is worrisome in ageing HIV-infected patients. Here, we aim to analyse the different ageing mechanisms with regard to HIV infection. Ageing results from the time-dependent accumulation of random cellular damage. Epigenetic modifications and mitochondrial DNA haplogroups modulate ageing. In antiretroviral treatment-controlled patients, epigenetic clock appears to be advanced, and some haplogroups are associated with HIV infection severity. Telomere shortening is enhanced in HIV-infected patients because of HIV and some nucleoside analogue reverse transcriptase inhibitors. Mitochondria-related oxidative stress and mitochondrial DNA mutations are increased during ageing and also by some nucleoside analogue reverse transcriptase inhibitors. Overall, increased inflammation or 'inflammageing' is a major driver of ageing and could result from cell senescence with secreted proinflammatory mediators, altered gut microbiota, and coinfections. In HIV-infected patients, the level of inflammation and innate immunity activation is enhanced and related to most comorbidities and to mortality. This status could result, in addition to age, from the virus itself or viral protein released from reservoirs, from HIV-enhanced gut permeability and dysbiosis, from antiretroviral treatment, from frequent cytomegalovirus and hepatitis C virus coinfections, and also from personal and environmental factors, as central fat accumulation or smoking. Adaptive immune activation and immunosenescence are associated with comorbidities and mortality in the general population but are less predictive in HIV-infected patients. Biomarkers to evaluate ageing in HIV-infected patients are required. Numerous systemic or cellular inflammatory, immune activation, oxidative stress, or senescence markers can be tested in serum or peripheral blood mononuclear cells. The novel European Study to Establish Biomarkers of Human Ageing MARK-AGE algorithm, evaluating the biological age, is currently assessed in HIV-infected patients and reveals an advanced biological age. Some enhanced inflammatory or innate immune activation markers are interesting but still not validated for the patient's follow-up. To be able to assess patients' biological age is an important objective to improve their healthspan.

HIV rapid testing in drug treatment: comparison across treatment modalities

Despite high rates of risky behavior among patients, many drug abuse treatment programs do not provide on-site HIV testing. This secondary analysis examined differences in outcome by program modality from a multi-site trial in which 1281 HIV-negative patients in three methadone programs, seven non-methadone outpatient programs, and three residential programs were randomly assigned to: (1) off-site referral for HIV risk reduction counseling and testing; or on-site rapid testing (2) with or (3) without risk reduction counseling. The parent study using generalized estimating equations with site as a cluster variable found significantly higher rates of HIV testing and feedback of results by 1 month post-enrollment for the combined on-site conditions compared to the offsite condition [RR=4.52, 97.5% CI (3.57, 5.72)]. Utilizing the same statistical approach, we found neither significant treatment modality nor significant treatment modality by testing condition interaction effects either for receipt of HIV test results at 1 month or for sexual or drug use HIV-risk behaviors at 6-month follow-up. On-site HIV testing is effective across treatment modalities for achieving high rates of testing and results feedback. All programs should be encouraged to adopt or expand this service.

NIDA's Clinical Trials Network: an opportunity for HIV research in community substance abuse treatment programs

BACKGROUND/OBJECTIVES

HIV continues to be a significant problem among substance users and their sexual partners in the United States. The National Drug Abuse Treatment Clinical Trials Network (CTN) offers a national platform for effectiveness trials of HIV interventions in community substance abuse treatment programs. This article presents the HIV activities of the CTN during its first 10 years.

RESULTS

While emphasizing CTN HIV protocols, this article reviews the (1) HIV context for this work; (2) the collaborative process among providers, researchers, and National Institute on Drug Abuse CTN staff, on which CTN HIV work was based; (3) results of CTN HIV protocols and HIV secondary analyses in CTN non-HIV protocols; and (4) implications for future HIV intervention effectiveness research in community substance abuse treatment programs.

CONCLUSION/SIGNIFICANCE

While the feasibility of engaging frontline providers in this research is highlighted, the limitations of small to medium effect sizes and weak adoption and sustainability in everyday practice are also discussed.

HIV and hepatitis B and C incidence rates in US correctional populations and high risk groups: a systematic review and meta-analysis

BACKGROUND

High Human Immunodeficiency Virus (HIV) prevalence and high risk behaviors have been well documented within United States (US) correctional systems. However, uncertainty remains regarding the extent to which placing people in prison or jail increases their risk of HIV infection, and regarding which inmate populations experience an increased incidence of HIV. Describing these dynamics more clearly is essential to understanding how inmates and former detainees may be a source for further spread of HIV to the general US population.

METHODS

The authors conducted a systematic review and meta-analysis of studies describing HIV incidence in US correctional facility residents and, for comparison, in high risk groups for HIV infection, such as non-incarcerated intravenous drug users (IVDU) and men who have sex with men (MSM) in the US. HIV incidence rates were further compared with Hepatitis B and Hepatitis C Virus rates in these same populations.

RESULTS

Thirty-six predominantly prospective cohort studies were included. Across all infection outcomes, continuously incarcerated inmates and treatment recruited IVDU showed the lowest incidence, while MSM and street recruited IVDU showed the highest. HIV incidence was highest among inmates released and re-incarcerated. Possible sources of heterogeneity identified among HIV studies were risk population and race.

CONCLUSIONS

Although important literature gaps were found, current evidence suggests that policies and interventions for HIV prevention in correctional populations should prioritize curtailing risk of infection during the post-release period. Future research should evaluate HIV incidence rates in inmate populations, accounting for proportion of high risk sub-groups.

The prevalence of human immunodeficiency virus infection among TB patients in Port Harcourt Nigeria

The joint statement by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America recommends that all patients with tuberculosis (TB) undergo testing for human immunodeficiency virus (HIV) infection after counseling. In this study, we investigated the prevalence of HIV infection among 120 patients diagnosed with microbiologically proven TB aged 18 to 54 years with a mean age of 39.5 years (standard deviation 6.75). The subjects studied were 36 male (30%) and 84 females (70%). Enzyme-linked immunosorbent assay methods were used to screen for HIV infection among the subjects. Of the 120 TB patients tested 30 (25%) were positive for HIV infection. The prevalence of HIV was higher in females 24 (80%) compared to males 6 (20%) and among singles (66.7%) compared to married subjects (33.3%) (χ(2) = 83.5 and χ(2) = 126.2, respectively P = 0.001). HIV-1 was the predominant viral subtype. HIV prevalence was significantly higher in subjects in the 38-47 year and 28-37 year age groups (both 40%) followed by the 18-28 year age group (20%) (χ(2) = 42.6, P = 0.05). The mean CD4 lymphocyte count of the HIV-infected TB subjects was significantly lower (195 ± 40.5 cells/μL) compared to the non-HIV infected (288 ± 35.25 cells/μL P = 0.01). This study has shown a high prevalence of HIV among TB patients. Reactivation of TB among people living with HIV can be reduced by TB preventive therapy and by universal access to antiretroviral therapy.

HIV/hepatitis prevention in drug abuse treatment programs: guidance from research

A large body of research examines the relationship between HIV and drug dependence, but considerably less information is available on viral hepatitis and drug dependence. This article summarizes research indicating what drug abuse treatment programs can do to prevent their patients from acquiring HIV or hepatitis infection and to limit the consequences for patients who are already infected. Drug treatment programs can play a pivotal role in preventing, detecting, and treating HIV and hepatitis. Some activities can be accomplished by providers simply becoming aware of the issues; others will require significant infusion of leadership, education, and fiscal support.

Detection of HIV-1 in injection paraphernalia: risk in an era of heightened awareness

Links between AIDS and self-injection of drugs were first recognized more than 20 years ago, but identification of a specific pathogen and ways to neutralize it has not led to complete success in preventing transmission of HIV-1 infection among injecting drug users (IDUs). A street ethnographer identified active risk locales (places where IDUs go to inject drugs) and recruited their proprietors into a study of contaminated injection paraphernalia. Collected paraphernalia from locales were analyzed for contamination by HIV-1 using real-time polymerase chain reaction (PCR). Proprietors and clientele of 16 risk locales participated by contributing used paraphernalia and/or agreeing to a blood test (0.5-1 mL drawn by finger stick). Realtime PCR was the primary measure used to determine contamination of injection paraphernalia and blood samples with HIV-1. Of 130 samples collected at baseline, a total of 8 were found to have evidence of HIV-1 contamination by detection of either HIV-1 RNA or DNA. The most serious contamination (up to 600,000 copies per milliliter) was found in ancillary paraphernalia, rather than needle/syringe (N/S) specimens. Only 4 of 74 N/S specimens had any evidence of HIV-1 contamination at all (with very low viral loads), and none had both HIV-1 DNA and RNA. Although IDUs in risk locales in Miami/Dade appear to be taking care of their N/S with regard to contamination by HIV-1, important evidence of contamination in ancillary paraphernalia, especially cookers and cottons, indicates that IDUs may still incur serious risk regardless of how well they care for their N/S. Our observations indicated that IDUs rinsed their N/S before returning them to the proprietors, from whom we eventually collected them, and this rinsing would have masked the contamination to which they were exposed through use of unrinsed cookers and reused cottons.

HIV among injection drug users in large US metropolitan areas, 1998

This article estimates HIV prevalence rates among injection drug users (IDUs) in 95 large US metropolitan areas to facilitate social and policy analyses of HIV epidemics. HIV prevalence rates among IDUs in these metropolitan areas were calculated by taking the mean of two estimates: (1) estimates based on regression adjustments to Centers for Disease Control and Prevention (CDC) Voluntary HIV Counseling and Testing data and (2) estimates based on the ratio of the number of injectors living with HIV to the number of injectors living in the metropolitan area. The validity of the resulting estimates was assessed. HIV prevalence rates varied from 2 to 28% (median 5.9%; interquartile range 4.0-10.2%). These HIV prevalence rates correlated with similar estimates calculated for 1992 and with two theoretically related phenomena: laws against over-the-counter purchase of syringes and income inequality. Despite limitations in the accuracy of these estimates, they can be used for structural analyses of the correlates, predictors and consequences of HIV prevalence rates among drug injectors in metropolitan areas and for assessing and targeting the service needs for drug injectors.

Trends of HIV risk behaviors in a cohort of injecting drug users and their sex partners in Miami, Florida, 1988-1998

A cohort of 111 injection drug users (IDUs) and their sex partners was assessed in 1988 concerning risk behaviors for HIV and knowledge of HIV/AIDS. Ten years later, in 1998, the cohort was reassessed using the same instrument. All who were HIV negative in 1988 were retested by blood draw for antibodies to HIV. A paired analysis was utilized to determine individual changes in risk behaviors for three serostatus groups--those who remained HIV negative (long-term HIV negatives), seroconverters, and those positive in 1988 (long-term HIV positives). Incidence was twice as high for sex partners (37.5%) as for IDUs (18.0%). Drug and needle use risk behaviors, except crack use, showed decreases; sexual risk behaviors were less amenable to change. Knowledge significantly increased among the long-term HIV negatives and seroconverters but not among those HIV positive in 1988. This analysis demonstrates the need for continued intervention among IDUs and their sex partners.

Prevalence and correlates of crack-cocaine injection among young injection drug users in the United States, 1997-1999

OBJECTIVES

We estimated prevalence and identified correlates of crack-cocaine injection among young injection drug users in the United States.

METHODS

We analyzed data from the second Collaborative Injection Drug Users Study (CIDUS II), a 1997-1999 cohort study of 18-30-year-old, street-recruited injection drug users from six US cities.

RESULTS

Crack-cocaine injection was reported by 329 (15%) of 2198 participants. Prevalence varied considerably by site (range, 1.5-28.0%). No participants injected only crack-cocaine. At four sites where crack-cocaine injection prevalence was greater than 10%, recent (past 6 months) crack-cocaine injection was correlated with recent daily injection and sharing of syringes, equipment, and drug solution. Lifetime crack-cocaine injection was correlated with using shooting galleries, initiating others into drug injection, and having serologic evidence of hepatitis B virus and hepatitis C virus infection.

CONCLUSIONS

Crack-cocaine injection may be a marker for high-risk behaviors that can be used to direct efforts to prevent HIV and other blood-borne viral infections.

Preventing HIV in injection drug users: choosing the best mix of interventions for the population

Injection drug users (IDUs) transmit the human immunodeficiency virus (HIV) via both needle sharing and sex. This analysis explores the effects of population risk behaviors, intervention effectiveness, intervention costs, and budget and capacity constraints when allocating funds between two prevention programs to maximize effectiveness. The two interventions, methadone maintenance and street outreach, address different types of risk behavior. We developed a model of the spread of HIV and divided IDUs into susceptible (uninfected) persons and infective persons and separately portrayed sex and injection risk. We simulated the epidemic in San Francisco, California, and New York City for periods from the mid-1980s to the mid-1990s and incorporated the behavioral effects of the two interventions. We used the simulation to find the allocation of a fixed budget to the two interventions that averted the greatest number of infections in the IDUs and their noninjecting sex partners. We assumed that interventions have increasing marginal costs. In the epidemic scenarios, our analysis found that the best allocation nearly always involves spending as much as possible on street outreach. This result is largely insensitive to variations in epidemic scenario, intervention efficacy, and cost. However, the absolute and relative benefits of the best allocation varied. In mid-1990s San Francisco, maximizing spending on outreach averted 3.5% of total HIV infections expected and 10 times the 0.3% from maximizing spending on treatment. In late 1980s New York City, the difference is five-fold (2.6% vs. 0.44%, respectively). Our analyses suggest that, even though prevention works better in higher risk scenarios, the choice of intervention mix is more important in the lower risk scenarios. Models and analyses such as those presented here may help decision makers adapt individual prevention programs to their own communities and to reallocate resources among programs to reflect the evolution of their own epidemics.

Gender differences in HIV risk behaviors among young injectors and their social network members

Using epidemiological and social network research methods, this study examines gender differences in HIV risk and protective behaviors and social network characteristics among 193 young injection drug users (IDUs) and 127 referred members of their social networks. Respondents reported on their drug use, sexual behavior, and relationships within three types of social networks: hang out (i.e., friendship); drug use; and sexual networks. Most respondents were homeless and had experienced numerous life stressors. Females' social networks consisted more predominantly of drug injectors, and members more frequently appeared multiple networks. Females reported needle sharing more frequently than males, but also reported more protective behaviors such as needle exchange use and carrying clean syringes. Young female IDUs may compound their risk by having sex and injecting with higher risk partners. However, their propensity to practice protective behaviors may provide an opening for interventions to reduce their HIV risk and that of their social network members.

Sexual decision making and safer sex behavior among young female injection drug users and female partners of IDUs

Data from interviews with 94 young women who were injection drug users (IDUs) or partners of IDUs were analyzed to examine associations between self-reported sexual decision making and condom use, contraceptive use, and relationship characteristics. Most women (73-85%) reported participating in decisions about condom use, contraception, and when to have sex. Adjusting for potential covariates, respondents who reported participating in decisions about condom use and when to have sex were 7 and 19 times, respectively, more likely than others to report recently using condoms. Respondents who reported participating in decisions about contraception were 20 times more likely than others to report recently using contraceptives. Longer sexual relationships were associated with decreased likelihood of condom or contraceptive use.

HIV incidence in the United States, 1978-1999

CONTEXT

HIV incidence measurements, which reflect recent or current transmission, are valuable for monitoring the epidemic and evaluating prevention programs.

OBJECTIVES

To summarize HIV incidence patterns and trends in U.S. population groups.

DATA SOURCES

Publications in English from 1980 through mid-2000. STUDY SELECTION AND STATISTICAL METHODS: We searched the literature for reports of HIV incidence in the United States. Locally weighted scatterplot smoothing was used to generate smooth curves to estimate trends in incidence. Spearman rank correlation was used to estimate the correlation coefficient between prevalence and incidence.

DATA SYNTHESIS

In 74 eligible reports, HIV incidence varied widely (0.002-19.8 per 100 person-years [py]) depending on risk group. Among men who have sex with men (MSM), HIV incidence peaked in the early 1980s (5-20/100 py) and then declined but remained high during the 1990s (2-4/100 py). Among injection drug users (IDUs), incidence decreased since the mid-1980s but differed by geographic area; in the 1990s, incidence remained high in the East (1-3/100 py) but was lower in the West (<0.5/100 py). Throughout the late 1980s and 1990s, incidence was low and stable in broader populations (blood donors: <0.01/100 py; military personnel: 0.01-0.07/100 py). The correlation between HIV incidence and prevalence was strong in populations with a prevalence less than 1% (r = 0.94, p<.0001), moderate in populations with a prevalence from 1% to less than 10% (r = 0.57, p<.0001), and weak in populations with a prevalence at least 10% (r = 0.23, p=.09).

CONCLUSIONS

HIV prevention in the United States should continue to focus on MSM and IDUs. HIV incidence measurements should be considered for monitoring HIV transmission in MSM, IDUs, and other populations in which seroprevalence is high.

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.