Search

Background: Asymptomatic Chlamydia trachomatis (CT) infection and other sexually transmitted infections in men potentially contribute significantly in sustaining the spread of the infection. To describe the distribution and related sexual behaviors, we conducted a cross-sectional study among young Thai men using a (1:30) systematic sampling of all newly inducted military conscripts in Thailand., Methods: In November 2008 and May 2009, participants' urine and serum samples were tested for CT and Neisseria gonorrhoeae, using a multiplex polymerase chain reaction technique, and serologic testing for Treponema pallidum and HIV-1 was done. Information on demographic data and risk behaviors was obtained by a self-administered questionnaire., Results: The overall prevalence rates of CT, N. gonorrhoeae, HIV-1, and syphilis infection were 7.9%, 0.9%, 0.5%, 0.05%, respectively. The risk factors for CT infection were living in the upper north region (adjusted rate ratios [95% confidence interval], 2.13 [1.39-3.26]), having had 4 or more sexual partners (2.14 [1.48-3.09]), graduation from a vocational school (1.66 [1.14-2.41]), inconsistent condom use (1.48 [1.05-2.08]), unemployment (1.82 [1.06-3.12]), and age 21 years or younger (1.63 [1.01-2.63])., Conclusions: The prevalence of CT infection among young male military conscripts was high, especially among men from upper northern Thailand. Multiple sexual partners, graduation from a vocational school, inconsistent condom use, unemployment before the military induction, and younger age were independently associated with the CT infection among young Thai men. These data will be useful to develop more effective public health interventions to prevent, detect, and treat sexually transmitted infections among young men in Thailand.

Epidemiologic studies of hepatitis C virus (HCV) infection are unusual in developing countries, especially Thailand. We evaluated the prevalence and risk factors for HCV among military conscripts, including a sample of 5,246 men (1:30 sample), and human immunodeficiency virus (HIV)-1 positive men (N = 500) between 2005 and 2008. The HCV prevalence was 2.2% in the sampled group and 8.4% in HIV-1 sero-positives. Among the sampled group, HIV-1 infection, injection drug use (IDU) history, and unsafe injections were associated with HCV infection; adjusted prevalence rate ratios [RRs; 95% confidence intervals (CIs)] were 3.7 (1.04-12.77), 1.9 (1.04-3.54), and 1.8 (1.02-3.11), respectively. Among HIV-1 sero-positives, an IDU history and residence in southern Thailand were associated with HCV prevalence; adjusted RRs (95% CIs) were 3.5 (1.71-7.24) and 2.6 (1.18-5.61), respectively. Public health measures to prevent HCV in Thailand should focus on reducing injection drug use and other exposures to unsafe injections among young Thai men.

Background: Estimation of the number of people in need of antiretroviral therapy (ART) in resource-limited settings requires information on the time from seroconversion to ART eligibility and from ART eligibility to death., Objectives: To estimate duration from seroconversion to different ART eligibility criteria and from ART eligibility to death in HIV-infected adults in low-income and middle-income countries., Methods: Participants with documented seroconversion from five cohorts (two cohorts from Uganda, two from Thailand and one from Côte d'Ivoire) were analysed. We used Weibull survival models and Bayesian simulation methods to model true (unobserved) first time of treatment eligibility. We set a consistency constraint so that the mean duration from seroconversion to death was equal to the mean from seroconversion to ART eligibility plus the mean from eligibility to death., Results: We analysed data from 2072 participants, 16 157 person-years of follow-up and 794 deaths. For the criterion CD4 T-lymphocyte count <200 cells x10(6)/l, the median duration from seroconversion to ART eligibility was 6.1 years (95% credibility interval 3.3-10.4) for all studies and 7.6 years (95% credibility interval 3.4-15.2) for all but the Thai cohorts. Corresponding estimates for the time from CD4 T-lymphocyte count <200 cells x10(6)/l to death were 2.1 years (0.7-4.8) and 2.7 years (0.8-8.4). When including all cohorts, the mean time from serconversion to CD4 T-lymphocyte count <200 cells x10(6)/l and from CD4 T-lymphocyte count <200 cells x10(6)/l to death represented 66% (38-87%) and 34% (13-62%), respectively of the total survival time., Conclusions: The duration of different ART eligibility criteria to death was longer than the estimates used in previous calculations of the number of people needing ART. However, uncertainty in estimates was considerable and heterogeneity across cohorts important.

Objectives: To estimate survival patterns after HIV infection in adults in low and middle-income countries., Design: An analysis of pooled data from eight different studies in six countries., Methods: HIV seroconverters were included from eight studies (three population-based, two occupational, and three clinic cohorts) if they were at least 15 years of age, and had no more than 4 years between the last HIV-negative and subsequent HIV-positive test. Four strata were defined: East African cohorts; South African miners cohort; Thai cohorts; Haitian clinic cohort. Kaplan-Meier functions were used to estimate survival patterns, and Weibull distributions were used to model and extend survival estimates. Analyses examined the effect of site, age, and sex on survival., Results: From 3823 eligible seroconverters, 1079 deaths were observed in 19 671 person-years of follow-up. Survival times varied by age and by study site. Adjusting to age 25-29 years at seroconversion, the median survival was longer in South African miners: 11.6 years [95% confidence interval (CI) 9.8-13.7] and East African cohorts: 11.1 years (95% CI 8.7-14.2) than in Haiti: 8.3 years (95% CI 3.2-21.4) and Thailand: 7.5 years (95% CI 5.4-10.4). Survival was similar for men and women, after adjustment for age at seroconversion and site., Conclusion: Without antiretroviral therapy, overall survival after HIV infection in African cohorts was similar to survival in high-income countries, with a similar pattern of faster progression at older ages at seroconversion. Survival appears to be significantly worse in Thailand where other, unmeasured factors may affect progression.

Background: We examined recent trends (1999-2004) in HIV incidence among a cohort of injection drug users (IDUs) followed since 1988 in Baltimore, Maryland., Methods: One thousand eighty-three HIV-seronegative individuals with a history of injection drug use were recruited between 1988 and 1998 and returned for >or=1 semiannual follow-up visit, where they underwent HIV antibody testing and interviews eliciting risk behaviors. Person-time methods were used to calculate HIV incidence rates per 100 person-years (PYs)., Results: Over 14,770 PYs, 304 individuals seroconverted to HIV (2.06 per 100 PYs). Annual incidence declined from 4.57 in 1988 to 0.53 per 100 PYs in 2004. Similarly, among individuals actively injecting drugs, incidence steadily declined from 5.43 in 1988 to 0 in 2004, with the exception of 2003, when an incidence of 2.59 per 100 PYs was observed. Reported sexual risk behaviors and drug injection declined from 1988 through 2004, but among those actively injecting, reported needle sharing declined from 1988 through 1998 and then increased from 30% in 1998 to nearly 40% in 2003 through 2004., Conclusions: Long-term declines in HIV incidence among IDUs are consistent with other reports; however, in 2003, we observed an unexpected increase in seroconversion that seems to be related to needle sharing. Although additional follow-up is needed to identify trends, these data indicate the need to reinforce HIV prevention efforts and to continue surveillance of drug users' behaviors.

Objectives: To quantify the association of HIV infection with overdose mortality and explore the potential mechanisms., Design: A prospective cohort study., Methods: A total of 1927 actively injecting drug users who were HIV seronegative at baseline, of whom 308 later HIV seroconverted, were followed semi-annually for death from 1988 to 2001. Survival analyses using marginal structural and standard Cox models were used to evaluate the effect of HIV infection on the risk of overdose mortality., Results: Overdose death rates were higher in HIV-seropositive than HIV-seronegative drug users: 13.9 and 5.6 per 1000 person-years, respectively (P < 0.01). The hazard ratio (HR) was 2.54 [95% confidence interval (CI) 1.47, 4.38] for the marginal structural model and 2.06 (95% CI 1.25, 3.38) for the standard Cox model, both adjusted for demographics, drug injection characteristics, alcohol abuse, substance abuse treatment, and sexual orientation. Adjusting for possible time-varying mediators (i.e. drug use, medical conditions and healthcare access) in extended marginal structural models reduced the effect of HIV on overdose mortality by 30% (HR 1.82, 95% CI 1.01, 3.30). Abnormal liver function was associated with a higher risk of overdose mortality (HR 2.00, 95% CI 1.05, 3.84); adjustment for this further reduced the effect of HIV on overdose mortality., Conclusion: HIV infection was associated with a higher risk of overdose mortality. Drug use behavior, systematic disease and liver damage associated with HIV infection appeared to account for a substantial portion of this association. The data suggest a group to target with interventions to reduce overdose mortality rates.

The natural history and progression of HIV-1 infection in Thailand and other developing countries in Asia and Africa have not been well defined. Nevertheless, valid data are needed to evaluate the effects of interventions, which are designed to delay progression. We evaluated the progression to AIDS and death in 235 men who seroconverted during their 2 years of service in the Royal Thai Army. The men were conscripted at age 21 and seroconverted within a 6-month window during follow-up while in the military. The seroconverters were matched with men who were seronegative when discharged. Of the HIV-positive men, 156 (66.4%) were alive, 77 (32.8%) had died, and 2 (0.8%) could not be located 5-7 years after their seroconversion and discharge from the military. The 5-year survival rate was 82.3%; the median times to clinical AIDS and a CD4 cell count of <200/microL was 7.4 years and 6.9 years, respectively. The mortality rate was 56.3 deaths per 1000 patient-years for HIV-positive men and 6.1 deaths per 1000 patient-years for HIV-negative men. Our data suggest a more rapid progression to AIDS and death after HIV-1 infection in young men in Thailand than has been reported for similarly aged cohorts in developed countries.

Aims: To investigate the demographic, sexual, and other substance use risk correlates of amphetamine use among men in northern Thailand prior to the current epidemic of amphetamine use in the Kingdom., Design: Cross-sectional quantitative behavioral questionnaires., Setting: Thai Ministry of Health STD and HIV Anonymous Test Sites in the upper northern provinces of Chiang Mai and Lamphun., Participants: Adult Thai men recruited at clinics for enrollment in an HIV seroincidence cohort study (The Thai HIVNET). All men were HIV negative at enrollment, and had at least one self-reported sexual risk for HIV infection (a recent STD, use of sex workers, multiple sexual partners, low or absent condom use, sex with men)., Measurements: Participants answered a structured questionnaire., Findings: Lifetime history of amphetamine use was reported by 133/914 men, 14.5%. Older age was protective for use (odds ratio (OR) 0.5) and use was associated with use of other substances; heroin (OR 7.1), thinner (OR 6.2), opium (OR 5.9), and marijuana (OR 5.7). Several STDs were associated with amphetamine use: gonorrhea (OR 2.3) and genital warts (OR 2.4), and any STD (OR 1.9). In multivariate analysis, use of heroin (OR 3.1), soft drugs (OR 4.9), and a history of gonorrhea (OR 2.0) were independently associated with amphetamine use in northern Thai men., Conclusions: Associations between young age, gonorrhea, other substance use and amphetamines indicate that prevention measures could occur at STD clinics and be incorporated into school programs when individuals are entering adolescence.

Although the incidence of and mortality from acquired immunodeficiency syndrome have declined recently in the United States, data are needed on the incidence of human immunodeficiency virus (HIV) and risk behaviors among injection drug users (IDUs). The authors studied the temporal trends of HIV incidence and risk behavior, ascertained through semiannual confidential interviews, between 1988 and 1998 in a cohort of 1,532 HIV-seronegative IDUs in Baltimore, Maryland. An additional 338 HIV-negative drug users were recruited in 1994 and were studied by using the same methods. Overall, 277 persons seroconverted to HIV during 8,826.45 person-years of follow-up, an incidence of 3.14 per 100 person-years. The incidence per 100 person-years declined over time from 4.45 in 1988-1990 to 3.35 in 1991-1994 to 1.84 in 1995-1998, a decline of 12% per year. HIV infections were associated with injection of cocaine, more frequent injection, needle sharing, and injection in a shooting galley. Sexual behavior variables associated with HIV incidence included a sexually transmitted infection, male homosexual behavior, and sex with another IDU. These data suggest that high-risk behavior and HIV incidence among IDUs have decreased recently in Baltimore. Nevertheless, additional prevention strategies are needed in these populations.

Objectives: To identify correlates of enrollment in methadone maintenance treatment programs (MMTP) among a prospective cohort of injection drug users (IDUs) in Baltimore, Maryland., Methods: A total of 1480 IDUs undergoing semi-annual HIV tests and interviews were studied between 1994 and 1998, during which time a needle exchange program was introduced. Longitudinal analysis using generalized estimating equations was used to identify correlates of MMTP participation over time., Results: Although similar proportions of HIV-seropositive and -seronegative IDUs enrolled in MMTP during follow-up (26 versus 22%, respectively), correlates of enrollment differed by HIV-serostatus. Among HIV-seropositive participants, older age [adjusted odds ratio (AOR, 1.37)] was associated with enrollment in MMTP. Among HIV-seronegative IDUs, factors associated with not enrolling in MMTP were being African American (AOR, 0.22) and having been recently incarcerated (AOR, 0.62) or homeless (AOR, 0.72). In both groups, females were twice as likely to be enrolled in MMTP, and those with Medicaid were 1.5 times more likely to be enrolled. When behavioral factors were lagged one visit, needle exchange program attendance was positively associated with MMTP enrollment among HIV-negative IDUs (AOR, 2.10); however, this association diminished significantly over time as dedicated treatment slots for needle exchange program participants became saturated., Conclusions: These findings underscore the need to improve access to MMTP, especially to certain subgroups such as African-Americans, the homeless, incarcerated and uninsured. Our data suggest that health care providers and needle exchange programs can facilitate enrollment into MMTP provided that adequate treatment slots are consistently available to this particularly vulnerable population.

Women who were partners of HIV-positive blood donors were enrolled in a study of heterosexual HIV transmission between March 1992 and December 1996 and were interviewed and examined. Gynaecological conditions, including cervical dysplasia, human papillomavirus (HPV) infection, gonorrhoea, chlamydial infection, trichomoniasis, bacterial vaginosis, vaginal candidiasis and syphilis were assessed in addition to HIV status and CD4 level. Of 481 women enrolled, 224 (46.6%) were HIV seropositive. HIV-infected women were more likely to have abnormal vaginal discharge on physical examination (OR=2.6, P <0.01), HPV infection with a high-risk type (OR=6.9, P <0.01), and cervical dysplasia (OR=5.3, P <0.01). The prevalence of other gynaecological conditions detected at the enrolment visit did not differ by HIV status. History of prior STD (OR=2.0, P <0.01) was more common among HIV-infected women. The median CD4 count was 400 cells/microl among HIV-infected women. The prevalence of abnormal vaginal discharge and bacterial vaginosis increased significantly with decreasing CD4 count. The prevalence of ectopy, vaginal candidiasis, and cervical dysplasia increased with decreasing CD4 count, but these trends were not significant. We conclude that HIV-infected Thai women appear to have increased prevalences of abnormal vaginal discharge, squamous intraepithelial lesions and self-reported history of STD.

Characterizing the epidemiology of HIV-1 infection in Northern Thai opiate users is important in developing control strategies in this ethnically diverse and culturally distinct region. A cross-sectional survey of drug users first admitted between 1993 and 1995 at the Northern Drug Dependence Treatment Center, Mae Rim, Thailand, was conducted. Patients (n = 4197) were interviewed at intake about their history of drug use when they provided serum specimens for HIV-1 antibody testing. The HIV-1 prevalence was 18.6%, with men having a fourfold higher prevalence than women. Wide diversity in HIV-1 prevalence was seen by ethnicity; the HIV-1 prevalence among Thai lowlanders was four times greater than that among ethnic minorities (hill tribes). Differences in HIV-1 prevalence were the result of differences in opiate use; hill tribes frequently smoked or ingested opium, whereas Thai lowlanders injected heroin. The high HIV-1 prevalence suggests that preventive interventions for risk reduction are urgently needed in these populations. Education about the risks of injection drug use (IDU) as well as information concerning needle disinfection and expansion of drug treatment are required to reduce the risk of HIV-1 transmission associated with sharing injection equipment. Further, increasing sources of sterile needles should be considered for active users, especially for those in more remote settings.

Objective: To describe risks for HIV transmission from male blood donors to their regular female sex partners in Chiang Mai, Thailand., Design: Cross-sectional study., Methods: From March 1992 through September 1995, 405 HIV-seropositive male blood donors (index cases) and their regular female partners were enrolled in the study. Women with risk factors for HIV infection other than sexual contact with the index male were excluded. Couples were interviewed and examined; specimens were collected for laboratory analysis., Results: Overall, 46% of the 405 women enrolled were HIV-positive. Ninety-eight per cent of male index cases had a history of sex with a female prostitute; 1.5% reported always using condoms with their regular partner. History of sexually transmitted disease (STD) and swollen inguinal lymph nodes in the female partner were associated with an increased risk of HIV infection in the female. History in the female of genital herpes [odds ratio (OR), 3.46; 95% confidence interval (CI), 1.50-8.78], gonorrhea or chlamydia infection (OR, 2.71; 95% CI, 1.39-5.53), and stable relationship of longer than 24 months (OR, 2.28; 95% CI, 1.02-5.09) were associated with an increased risk of HIV infection in the female. Consistent condom use in the past 2 years (OR, 0.10; 95% CI, 0.01-0.79) was associated with a decreased risk of HIV infection in the female., Conclusions: Married women in northern Thailand who appear otherwise to be at low risk for HIV infection may be exposed to this virus by their husbands. High rates of sex with commercial sex workers among men and low use of condoms within stable relationships may be important factors promoting the transmission of HIV in married couples. Programs to increase the regular use of condoms among married couples could be an important public health intervention to prevent transmission of HIV and other types of STD in northern Thailand.

Background: The epidemic of Human Immunodeficiency Virus (HIV) infection led blood banks to initiate donation deferral criteria based on self-reported risk factors. However little information is available on the differences in reporting risk factors before and after HIV status is known., Methods: Between April and July 1994, blood donors in a provincial hospital in northern. Thailand were interviewed at the time of donation, about their demographic characteristics and risk factors. All donors had agreed to learn their test results and were called back for post-test counselling and reinterview., Results: HIV-positive blood donors were more likely to change from 'denying' to 'acknowledging' risk factors while HIV-negatives were more likely to change from 'acknowledging' to 'denying'. The differences between risk factors obtained before and after test results were known resulted in stronger, weaker or even opposite risk measures., Conclusion: The study results raise questions about the impact of the differences in reporting HIV-related risk factors by the donors on how effective donation deferral criteria can be developed.

Despite mandatory antibody testing, human immunodeficiency virus (HIV) can be transmitted from HIV-infected blood that is seronegative. The objective of this study was to estimate the probability of HIV-infected blood donations during the seronegative "window period" in a northern Thailand HIV epicenter. Thus, a retrospective cohort of repeat blood donors was created. With the assumptions that the probability of HIV seroconversion is distributed uniformly between the last HIV-negative and the first HIV-positive donation and that the seronegative window is 45 days, the rate of window-period donations was calculated by multiplying the incidence by the window duration. Of 11,232 repeat donors, 273 seroconverted during 9,518,863 person-days of observation (i.e., a window-period donation rate of 1/775). There were more window-period donations among 21- to 30-year-old men and in donors replacing blood of friends or relatives. Additional measures are needed to reduce the high number of HIV-infected window-period donations.

Classification of human immunodeficiency virus type 1 (HIV-1) by neutralization serotype may be important for the design of active and passive immunization strategies. Neutralizing antibody serotyping is hindered by the lack of standard reagents and assay format, and by the weak activity of many individual sera. To facilitate cross-clade neutralization analysis, we used an infectivity reduction assay (IRA) and selected clade-specific serum (or plasma) pools from subjects infected with clade B and E HIV-1, respectively. Several serum pools were utilized; some were selected for strong neutralizing activity against intraclade viruses and others were derived from conveniently available samples. Against a panel of 51 clade B and E viruses, serum pools displayed strong neutralization of most intraclade viruses and significantly diminished cross-clade neutralization. Results were confirmed against a blinded panel of 20 viruses. The data indicate that the phylogenetic classification of virus subtypes B and E corresponds to two distinct neutralization serotypes. This approach to neutralizing antibody serotyping may be useful in defining the antigenic relationship among viruses from other clades.

Objectives: The aims of this study were to (1) identify trends and risk factors for mycobacterial disease and (2) determine the effect of expanded access to isoniazid chemoprophylaxis on tuberculosis incidence., Methods: A prospective observational cohort study was conducted among community-based injecting drug users (IDUs); 2960 IDUs (942 human immunodeficiency virus [HIV] seropositive) were followed up from January 1988 to June 1994. Directly observed chemoprophylaxis with twice-weekly isoniazid (10 to 15 mg/kg) was offered to purified protein derivative (PPD) tuberculin-positive (> or = 5-mm induration diameter in HIV-seropositive subjects and > or = 10-mm diameter in HIV-seronegative subjects) individuals but not to those with cutaneous anergy. Overall and annual incidence rates of disease due Mycobacterium tuberculosis, Mycobacterium avium complex, and other atypical mycobacteria were estimated using Poisson regression., Results: HIV seropositivity was the strongest risk factor for tuberculosis, M avium complex, and other mycobacterial disease (relative risk [RR], 3.8, 17.2, and 6.9, respectively). Median CD4 lymphocyte cell counts for the three groups of mycobacterial disease were 0.17, 0.03, and 0.02 x 10(9)/L (167/microL, 30/microL, 18/microL) within 6 months of diagnosis (before or after). Overall incidence rates of tuberculosis, M avium complex disease, and other mycobacterial disease were 1.9, 8.8, and 2.7 per 1000 person-years, respectively. Tuberculosis incidence peaked in 1991 at six per 1000 person-years. However, after access to directly observed preventive therapy was expanded for tuberculin-positive subjects, incidence fell to only one case in 1992 and zero cases for 24 months from mid-1992 to mid-1994. During this period the number of PPD-positive patients who completed at least 26 weeks of therapy (or were still receiving isoniazid) more than tripled (from 21 to 70). None of the 12 patients with tuberculosis diagnosed during follow-up had received any preventive therapy. In addition, no tuberculosis developed among participants with cutaneous anergy. Calendar trends in risk for M avium complex and tuberculosis diverged after expanded access to isoniazid prophylaxis. Compared with 1988-1989, risk of M avium complex increased sevenfold. Tuberculosis risk fell 83% from the peak risk in 1990-1991., Conclusions: Expanded access to directly observed isonazid therapy for tuberculin-positive IDUs with and without HIV infection was associated with an 83% drop in tuberculosis incidence, while in the same period M avium complex incidence significantly increased. These population-based data are consistent with those obtained from clinical trials of isoniazid prophylaxis and were obtained without offering chemoprophylaxis to HIV-infected patients with cutaneous energy.

Background: The purpose of this study was to develop human immunodeficiency virus (HIV) infection donation deferral criteria for blood donors in an HIV-epidemic area of northern Thailand, where the predominant means of transmission of HIV is through heterosexual contact., Study Design and Methods: In a preliminary study, 2242 blood donors were interviewed, and their blood was tested for HIV antibodies between September 1993 and April 1994. The risk factors associated with HIV positivity were identified. Criteria to identify HIV-positive persons on the basis of a logistic equation were developed and applied to another group of 5769 prospective blood donors., Results: A multivariate analysis showed the following odds ratios (OR) for traits that were independently associated with HIV positivity: younger age (OR = 0.93 for each additional year of age), male gender (OR = 2.41), having no more than a primary school education (OR = 2.00), being in the military (OR = 1.78), being unsure of one's own blood safety (OR = 2.00), history of injecting drug use (OR = 5.36), diagnosis of syphilis or positive syphilis serologic test in the past 12 months (OR = 2.67), and genital ulcer in the past 12 months (OR = 4.56). On the basis of the model, with a limit of <10 percent loss of uninfected donors, predicted probabilities of HIV positivity alone or of markers of infection with HIV, hepatitis B virus, or Treponema pallidum were calculated. With a cutoff of 6.5-percent estimated probability of HIV infection, derived from the logistic equation, the donor deferral criteria have 33.6-percent sensitivity and 8.3-percent positive predictive value for HIV positivity and 15.5-percent sensitivity and 18.4-percent positive predictive value for markers of infection with one of the three pathogens., Conclusion: The proposed donor deferral system provides a more flexible, sensitive, and predictive tool for averting donation by those who, though HIV antibody-negative, are at a higher risk of being infected with HIV.

Objective: To identify behavioral and sociodemographic risk factors for incident human immunodeficiency virus-1 (HIV-1) infection among healthy young men in northern Thailand., Design: Men inducted into military service in northern Thailand in May and November 1991 were followed at 6-month intervals until discharge 2 years later. Trained nonmilitary interviewers identified risk factors for HIV-1 infection through interviews with the men., Setting: Thirteen military bases in northern Thailand., Participants: A total of 1932 seronegative men, aged 19 to 23 years (average age, 21 years) at enrollment, conscripted into the Royal Thai Army and Air Force from six upper-northern Thai provinces., Main Outcome Measures: Human immunodeficiency virus-1 seroincidence as determined through enzyme-linked immunosorbent assay and verified by Western blot, and univariate and multivariate analyses of risk factors related to HIV-1 incidence., Results: A total of 85 men seroconverted to HIV-1 over the period of observation, giving an incidence rate of 2.43 per 100 person-years. Factors strongly associated with HIV-1 seroconversion were frequency of visits to female commercial sex workers (CSWs), sex with men, and incident sexually transmitted diseases (STDs). High frequency of condom use showed a significant (P < .001) protective effect for HIV-1 incidence among men with a history of recent sex with female CSWs in univariate analysis, but a multivariate model demonstrated no difference in HIV-1 seroconversion rates by consistency of condom use. Multivariate analysis incorporating condom use showed that having sex with men (adjusted relative risk [RR], 2.59; 95% confidence interval [CI], 1.08 to 6.25), having sex with CSWs (adjusted RR ranged from 2.54 [95% CI, 1.81 to 3.58] to 2.74 [95% CI, 1.56 to 4.81]), and incident STDs (adjusted RR, 2.38 [95%, CI, 1.31 to 4.32]) to be predictors of incident HIV-1 infection. Substance use was not associated with HIV-1 seroconversion rates in multivariate analysis., Conclusion: The HIV-1 incidence in this cohort of young men appears to be primarily attributable to having sex with female CSWs. Condom use provided some protection, although not in multivariate analysis; however, condom use has previously been shown likely to be useful in preventing HIV-1 transmission. Thus, programs to increase effective condom use in brothels are essential. Efforts to extend condom use to non-CSW partners are especially needed. More effective prevention and treatment of STDs may also be necessary to decrease HIV-1 infection in this population.

Objective: To measure the temporal trends in the incidence of infection with human immunodeficiency virus in a cohort of injecting drug users in Baltimore, Md, between 1988 and 1992., Design: Study subjects were screened for antibodies to human immunodeficiency virus by enzyme-linked immunosorbent assay and confirmed with Western blot. They were followed up at 6-month intervals with repeated serologic screening and comprehensive interviews for human immunodeficiency virus risk factors., Setting: Special study clinic., Participants: A cohort of 2960 participants were recruited and screened between February 1988 and March 1989. Recruitment criteria included an age of 18 years or older, a history of illicit drug injection since 1978, and the absence of the acquired immunodeficiency syndrome; subjects were subsequently tested for human immunodeficiency virus antibodies. Most subjects (85%) were not receiving methadone treatment at baseline and were recruited by word of mouth., Main Outcome Measure: Human immunodeficiency virus seroconversion., Results: Of the 2247 seronegative participants at baseline, 1532 were followed up, and 188 (12.3%) had seroconverted by December 1992. The incidence of human immunodeficiency virus infection over time among users declined somewhat, especially among women; the overall incidence was 1.90 per 100 person-semesters, or 3.80% annually. The incidence, adjusted for gender, was higher in younger (< 35 years) than older (> or = 35 years) subjects (relative incidence, 1.75; 95% confidence interval, 1.29 to 2.38) and in women compared with men, adjusted for age (relative incidence, 1.29; 95% confidence interval, 0.95 to 1.80). The relative incidence among active compared with inactive drug users adjusted for age and gender was 1.58 (95% confidence interval, 1.06 to 2.35)., Conclusions: Although the incidence of human immunodeficiency virus infection in this cohort of injecting drug users in Baltimore declined somewhat during the 4 years of follow-up, especially among women, the persistent annual incidence of nearly 4% during 3 1/2 to 4 1/2 years of observation suggests the need for additional strategies for prevention of infection, especially among those who continue injecting drugs. Newer methods of prevention, such as provision of sterile injection equipment, an effective human immunodeficiency virus vaccine, and wider availability of effective treatment or prevention of drug addiction, are urgently needed in these high-risk populations.

Background: Almost all human immunodeficiency virus (HIV) transmission via blood or tissues that has occurred since anti-HIV screening was implemented in 1985 is traceable to blood given after infection but before antibody seroconversion, a time that is referred to as the window period. In this study, the performance of newer assays designed to detect viral and serologic markers soon after infection is assessed, and the reduction in the window period achieved by these assays is estimated., Study Design and Methods: Three cohort studies of persons at high risk for acquiring HIV infection were identified. These studies included well-controlled HIV type 1 (HIV-1) polymerase chain reaction (PCR) analyses of serial preseroconversion specimens from HIV-1-seroconverting homosexual men or intravenous drug users. Of 81 enrollees with anti-HIV-1 seroconversion documented by a viral lysate anti-HIV-1 enzyme immunosorbent assay (EIA) available in 1989, 13 (16%) had PCR-positive preseroconversion specimens. In the present study, sera from these 13 PCR-positive samples were further tested for anti-HIV by 10 contemporary EIAs and 6 supplemental assays, as well as being tested for plasma p24 antigen and HIV-1 RNA. Preseroconversion sera from 38 HIV-1 DNA PCR-negative cohort participants were also tested by selected anti-HIV EIAs and tested for p24 antigen and HIV-1 RNA. On the basis of these laboratory data and the intervals between blood drawing in all 81 men, the reduction in the preseroconversion window period achieved by these new assays was estimated with a mathematical model developed to analyze seroconversion data., Results: Nine (69%) of the 13 preseroconversion PCR-positive samples had anti-HIV that was detectable by one or more contemporary anti-HIV-1 or anti-HIV type 2 EIA. Supplemental antibody assays were negative on all four EIA-nonreactive preseroconversion samples and negative or indeterminate on a high proportion of the nine EIA-reactive PCR-positive samples. Eight (61%) of the 13 samples were p24 antigen-positive, and 11 (85%) were HIV-1 RNA-positive. The estimated reductions in the window period (relative to the index viral lysate-based anti-HIV EIA) were as follows: contemporary anti-HIV-1/2 EIAs, 20.3 days (95% Cl, 8.0-32.5); p24 antigen and DNA PCR, 26.4 days (95% Cl, 12.6-38.7); and RNA PCR, 31.0 days (95% Cl, 16.7-45.3)., Conclusion: Recent improvement in the sensitivity of anti-HIV assays has resulted in significant shortening of the preseroconversion window period. Consequently, the incremental reduction in the window period that could be achieved by implementing direct virus-detection assays has diminished significantly.

To examine the risk factors for the first episode of bacterial pneumonia among human immunodeficiency virus (HIV)-seropositive injection drug users (IDUs), medical record review was performed on IDUs participating in a cohort study from January 1988 to June 30, 1992. HIV-seropositive IDUs with a first episode of bacterial pneumonia (n = 40) were matched with up to five HIV-seropositive control subjects without bacterial pneumonia (n = 197) by date of entry (+/- 3 mo) and length of follow-up. Odds ratios (OR) were estimated using conditional logistic regression. The incidence of bacterial pneumonia was 1.93 in 100 person-years in HIV seropositive and 0.45 in 100 person-years in HIV seronegative subjects (relative incidence = 4.3; 95% CI 2.4 to 7.5). In univariate analyses, CD4 lymphocyte count < 200 cells/microliters previous episode of Pneumocystis carinii pneumonia (PCP), age between 30 and 40 yr and smoking illicit drugs (marijuana, cocaine, or crack) were associated with bacterial pneumonia. Cigarette smoking was associated with an increased odds of bacterial pneumonia (OR = 2.0), but this was not statistically significant because it was nearly universal in this cohort. In multivariate analysis, CD4 < 200 cells/microliters (OR = 6.75, 95% CI 2.13 to 21.42) and smoking illicit drugs (OR = 2.24, 95% CI 1.03 to 4.89) remained significantly associated with bacterial pneumonia. The odds ratio for cigarette smoking in the final model remained at 2.08 but was still not significant (95% CI 0.49 to 8.70). Smoking illicit drugs had the strongest effect on risk of bacterial pneumonia among HIV-seropositive IDUs with a previous history of PCP (OR = 22.94; 95% CI 2.18 to 241.10).

Background and Methods: To compare rates of decline of CD4+ lymphocytes among human immunodeficiency virus-positive homosexual men and injecting drug users, we followed up prevalent human immunodeficiency virus-positive homosexual men and current or former injecting drug users from February 1988 through August 1991. Subjects were free of acquired immunodeficiency syndrome at study entry and had semiannual clinical and laboratory evaluation, including measurement of T-cell subsets, under common protocols. Initial levels and rates of change of CD4+ lymphocyte counts were compared according to cohort membership and clinical progression, defined by the development of thrush or an acquired immunodeficiency syndrome--defining illness. Median follow-up was 30 months for both cohorts., Results: At study entry, homosexual men had lower absolute numbers of circulating CD4+ lymphocytes than did injecting drug users (459/microL [0.46 x 10(9)/L] vs 509/microL, respectively). During follow-up, homosexual men exhibited a faster decline in CD4+ lymphocyte counts as well as more frequent development of HIV-related symptoms (thrush or acquired immunodeficiency syndrome). In both cohorts, initial levels of CD4+ lymphocytes and rates of decline in these cells were strongly associated with progression of disease, defined as remaining asymptomatic, onset of thrush, or onset of acquired immunodeficiency syndrome. Once homosexual men and injecting drug users were stratified by disease progression, their initial levels and rates of decline of CD4+ lymphocyte counts were similar. Thus, crude differences between the two study groups largely resulted from differences in development of clinical symptoms., Conclusions: In these cohorts of homosexual men and injecting drug users, clinical outcome was much more important than risk group membership in determining changes in CD4+ lymphocyte numbers. The close similarity between the groups also suggests that drug use, ethnicity, and socioeconomic status play a minor role in the progression of human immunodeficiency virus infection.

Objectives: Data from 538 women in a cohort study recruited in 1988-1989 were analyzed to determined whether trading sex for drugs or money was independently associated with human immunodeficiency virus (HIV) seroprevalence in a population of female intravenous drug users., Methods: The women were grouped according to the number of partners with whom they reported trading sex for drugs or money during the previous 10 years: none, 1 through 49 (low), or 50 or more (high); the prevalence of HIV seropositivity in the three groups was 23.2%, 23.7%, and 47.6%, respectively. Logistic regression was used to compare the low- and high-trade groups separately with the group that reported no trading., Results: Low trading was not associated with seroprevalent HIV infection. In a multivariate model, high trading (compared with no trading) was significantly associated with HIV seropositivity after adjustment for cocaine use, history of sexually transmitted diseases, and duration of intravenous drug use., Conclusions: These data indicate that, among intravenous drug-using women, high levels of trading sex for drugs or money were independently associated with HIV infection. This group needs to be targeted for further intensive intervention.

To examine sex-specific risk factors for human immunodeficiency virus (HIV) type 1 seroconversion among intravenous drug users, the authors conducted a nested case-control study in Baltimore, Maryland, from 1988 to 1992 comparing 146 seroconverters and 539 HIV seronegative controls. Controls were matched on sex, race, date of study entry, and duration of follow-up. Risk factor data were obtained from interviews conducted at the first seroconversion visit for the case and the closest visit for the corresponding seronegative control. Since test results were not available until several weeks after interview, both interviewers and participants were unaware of seroconversion status at the time of interview. When data were analyzed using conditional logistic regression techniques, the variables which were significantly associated with seroconversion among male intravenous drug users included age less than 35 years, a sexually transmitted disease within the past 6 months, lifetime history of syphilis, and current intravenous drug use with an abscess at the injection site. Among women, only a history of three or more sex partners was positively associated with seroconversion and having a biological child under age 18 years was inversely associated with HIV seroconversion. Although the small sample size may have limited the ability to ascertain differences in risks of seroconversion among males and females, these data suggest that sexual transmission contributes to HIV infection among intravenous drug users, especially women.

Objective: To determine whether injecting drug use is associated with cellular immune activation in the absence of HIV-1 infection., Design: Serum levels of neopterin and beta 2-microglobulin (beta 2M) were measured cross-sectionally in injecting drug users (IDU) enrolled in a prospective study., Subjects and Methods: Two hundred and nineteen HIV-1-seronegative, healthy heterosexual black male IDU aged 21-49 years were selected from the Baltimore-based AIDS Linked to Intravenous Experiences (ALIVE) study. The possibility of including subjects in the process of seroconverting to HIV-1 was minimized by restricting the study to individuals who remained seronegative 6 months after the specimens used for analysis were collected., Results: Mean serum beta 2M levels were not statistically different among groups of IDU whose usual pattern of injection was at least once a day for up to 3 consecutive days (daily users; n = 65), less than once per day (less-than-daily users; n = 75), or not at all for at least 2 weeks (non-recent users; n = 79). In contrast, the mean neopterin level was significantly (P = 0.039) greater in daily users (6.17 nmol/l) than in the other two groups (5.07 and 5.19 nmol/l, respectively, which were not statistically different). These results were not affected, by the frequency of using borrowed non-sterile works or by other demographic and risk factor variables., Conclusions: Frequent injecting drug use may be independently associated with a small elevation of serum neopterin levels, but not beta 2M levels. Although the occurrence of a type I error in this sample cannot be completely excluded, serum neopterin may be more sensitive than serum beta 2M in detecting activation of immunocompetent cells associated with frequent injecting drug use in this population.

Objective: To evaluate changes in T-cell subsets in prevalent human immunodeficiency virus type 1 (HIV-1) seronegative and seropositive intravenous drug users (IVDUs) and in HIV-1 seropositive IVDUs with known time of seroconversion., Design: Cohort study with a median 18-month follow-up., Setting: Community-based clinic established to study the natural history of HIV infection in IVDUs., Subjects: Eight hundred fifty-nine self-referred IVDUs aged 18 through 49 years who injected drugs within the last 10 years and who did not have an AIDS (acquired immunodeficiency syndrome)--defining illness; 152 were seronegative for HIV-1, 621 were seropositive, and 86 seroconverted during the study., Outcome Measures: Proportions and absolute numbers of lymphocytes and CD3, CD4, and CD8 T cells as determined at 6-month intervals by flow cytometry and complete blood cell counts with automated differential., Results: Median numbers of CD4 lymphocytes at enrollment were 1061/microL (1.06 x 10(9)/L) for seronegative IVDUs, 508/microL for seropositive IVDUs, and 733/microL for those who seroconverted (enrolled a median of 4.5 months after seroconversion); the corresponding figures for CD8 lymphocytes were 628, 894, and 889/microL, respectively. Median rates of decline in absolute numbers and percentages of CD4 lymphocytes per 6 months were 7.6/microL (0.0%) for seropositive IVDUs and 55.1/microL (1.9%) for IVDUs who seroconverted (median follow-up after seroconversion was 12 months). Multivariate regression analysis that incorporated the within-individual correlation of the CD4 lymphocyte counts showed no significant change in these cells over time and no change due to use of drugs., Conclusion: Our data suggest that progression of HIV-1 infection in IVDUs, as reflected in decline of CD4 cell counts, is no more rapid than that reported for other risk groups.

Objectives: --To identify differences in purified protein derivative (PPD) tuberculin positivity and skin test anergy rates by human immunodeficiency virus (HIV) serostatus, CD4+ lymphocyte count, and other risk factors in intravenous drug users (IVDUs); and to evaluate the appropriateness of the Centers for Disease Control (CDC)--recommended definition for a positive PPD tuberculin skin test result in HIV-1-seropositive patients., Design: --Nested case-control and cross-sectional analyses., Setting: --Community-based cohort of IVDUs., Patients: --Two hundred sixty HIV-1-seropositive and -seronegative IVDUs, drawn from an unselected cohort, were skin-tested for sensitivity to PPD tuberculin, mumps, and Candida antigens using the Mantoux method., Outcome Measures: --Positivity to PPD tuberculin, skin test anergy., Results: --Even using the CDC definition of an induration 5 mm or greater in diameter in HIV-1 seropositives, this group was substantially less likely to be PPD tuberculin positive than HIV-1 seronegatives (13.8% vs 25.2%; P = .02). In the HIV-1 seropositives the relative odds of being PPD positive varied depending on whether 10 mm or greater (odds ratio [OR], 0.3; 95% confidence interval [CI], 0.2 to 0.7), 5 mm or greater (OR, 0.5; 95% CI, 0.2 to 0.9), or 2 mm or greater (OR, 0.7; 95% CI, 0.4 to 1.3) was used to define a positive test result. The mean diameter induration in the HIV-1-seropositive group was 2.6 mm vs 5.4 mm in the seronegative group (P = .005). Skin test anergy (to mumps and Candida) appeared to explain the differential. Anergy was substantially higher in the HIV-1 seropositive group and increased as the CD4+ lymphocyte count fell (chi 2 for linear trend, 24.5; P less than .0001). An inverse linear trend for PPD positivity and CD4+ lymphocyte count was also observed (chi 2 for trend, 6.1; P = .01). In multivariate analyses, being 35 years of age or older and being HIV-1 seronegative were significantly associated with PPD positivity, while history of previous police arrest was of borderline significance. Only HIV-1 seropositivity was significantly associated with anergy., Conclusions: --These findings show that CDC-recommended definition of an induration 5 mm or greater in diameter for PPD tuberculin positivity in HIV-1 seropositives significantly underestimates the "true" infection rate (using the PPD positivity rate in HIV-1 seronegatives as the criterion standard). A definition of 2 mm or greater would appear to be a better cutoff for reducing misclassification in HIV-1 seropositives. This study also confirms that delayed-type hypersensitivity is seriously depressed in HIV-1 seropositive IVDUs and that anergy testing is mandatory to properly assess a negative PPD test result.

To examine the putative protective effect of disinfectant use on HIV seroconversion among intravenous drug users, we conducted a nested case-control study comparing 22 black heterosexual HIV seroconverters with 95 persistent seronegatives matched on gender, use of cocaine, date of study entry, and duration of follow-up. For intravenous drug users who reported using disinfectant all the time, the odds of seroconversion was 0.77 (95% CI: 0.25-2.38) compared with those who reported no use of disinfectants; for those who used disinfectants some of the time, the corresponding odds ratio was 0.91 (95% CI: 0.26-3.31). The odds ratio for use of disinfectant all the time was 0.63 (95% CI: 0.10-3.91) for those injecting at galleries and 1.08 (95% CI: 0.35-3.11) for those not injecting at galleries. These data suggest a limited protective effect of disinfectant use in the field which may be more beneficial to those injecting in shooting galleries.

The association between human immunodeficiency virus (HIV) seropositivity and a history of sexually transmitted diseases (STDs), evidence of STDs on physical examination, and sexual and drug use practices was studied in a population of 2921 intravenous drug users (IVDUs) in Baltimore during 1988 and 1989. Overall, 24.1% were HIV-seropositive at baseline, and 60% reported a history of an STD. A significant association was found between HIV seropositivity and a history of syphilis (P = .04); both were more frequent among homosexual/bisexual men than among heterosexual IVDUs. In multivariate analysis, a history of syphilis was independently associated with HIV seroprevalence in homosexual/bisexual male IVDUs, of whom 90% reported a history of sexual intercourse with women. Cocaine injection was independently associated with HIV seropositivity but not a history of syphilis on multivariate analysis. STDs, indicative of unsafe sex practices, are common in this population; efforts are needed to prevent sexual transmission of HIV infection among IVDUs and their sex partners.

During 1988 and 1989, intravenous drug users recruited through extensive community outreach efforts in Baltimore, Maryland, were interviewed about drug injection and sex practices in the prior 11 years, with screening for antibody to human immunodeficiency virus type 1 (HIV-1). Neither interviewers nor subjects were aware of HIV-1 serostatus until 2 weeks after the interview. Among 2,616 intravenous drug users who last injected drug within the same calendar year as screening, HIV-1 seroprevalence was 30.1% for those with any use of shooting galleries, 23.3% for those who shared needles but did not use shooting galleries, and 16.3% for drug users who denied both needle-sharing and gallery use between 1977 and 1987. Among 608 drug users who reported persistent use of shooting galleries since 1977 or subsequent initiation into drug use, there was a tendency for HIV-1 seroprevalence to increase with more recent onset of an injection career. Combined with a milder but similar tendency among 739 drug users who reported persistent sharing of needles, and a seroprevalence of 15.1% among participants who had just started injecting drugs in the 18 months prior to baseline, these data provide indirect evidence that a high risk for HIV-1 infection might occur early during a drug injection career.

Study Objective: To ascertain whether subjects infected with human immunodeficiency virus (HIV) generally develop protective hemagglutination inhibition antibody responses to inactivated influenza vaccines., Design: Prospective study of 104 persons before and after immunization., Setting: Outpatient clinic and hospital ward., Patients: Persons with the acquired immunodeficiency syndrome (AIDS) (n = 25), AIDS-related complex (n = 14), and HIV-seropositive men with only lymphadenopathy or no symptoms (n = 27). Controls were HIV-seronegative homosexual men (n = 22) and HIV-seronegative heterosexuals (n = 16)., Interventions: Subjects were immunized with inactivated vaccines containing 15 micrograms of each of the following influenza virus hemagglutinins: A/Taiwan/1/86 (HINI), A/Mississippi/1/85 (H3N2), A/Chile/1/83 (HINI), and B/Ann Arbor/1/86., Measurements and Main Results: Fourfold or greater antibody responses occurred less frequently in subjects with HIV infections than in HIV-seronegative controls. Protective levels (1:64 or greater) of hemagglutination inhibition antibodies were attained by 94% to 100% of HIV-seronegative controls, 52% to 89% of HIV-seropositive asymptomatic subjects, and 13% to 50% of subjects with AIDS or AIDS-related complex. No increase in the prevalence or level of serum HIV p24 antigen or clinical deterioration was detected among HIV-infected persons after influenza immunization., Conclusions: Because of the poor antibody responses to influenza vaccines among HIV-infected subjects, even in many with no or minimal symptoms, alternative strategies for preventing influenza, such as booster doses of influenza vaccine, prophylaxis with amantidine, or both should be considered.