Epidemiology of hepatitis B virus infections among injecting drug users: seroprevalence, risk factors, and viral interactions.
Explore the source record for details and available documents.
Blood-Borne Pathogens↗
Biomedical subjects
K E Nelson
Publications and source records attributed to K E Nelson.
HIV-1 infection among lower class commercial sex workers in Chiang Mai, Thailand.
OBJECTIVE: To determine risk factors for HIV-1 infection in female commercial sex workers (CSW) in northern Thailand. METHODS: A cross-sectional survey of female CSW from 11 sex establishments frequented by military conscripts that included an interview and serological testing for HIV-1. RESULTS: The HIV-1 seroprevalence in 230 CSW was 65%; the rate was lower among CSW from Chiang Mai than from rural areas. Multivariate logistic regression analysis for HIV-1 included the following significant factors: non-urban location of the sex establishment, ethnic Thai lowlander, lower price, history of genital warts and dysuria. Condom use, number of partners and duration of employment were not significantly associated with HIV-1 prevalence after adjustment for other risk factors. CONCLUSIONS: The high level of HIV-1 seroprevalence in this sample demonstrates the risk of transmission in lower cost commercial sex encounters in northern Thailand. Non-Thais (ethnic Hill tribes and Burmese) had lower HIV-1 prevalence than ethnic Thais. Type of establishment ('direct' brothel-based or 'indirect' establishments) was not predictive of HIV-1 seroprevalence. However, rural establishments were less vigilant in promoting condom use, suggesting the need for renewed efforts to enforce the Ministry of Public Health's '100% Condom Campaign' in commercial sex establishments.
Adolescent↗
Comparison of clinical manifestations of HIV infection between male and female injecting drug users.
OBJECTIVE: To compare occurrence of clinical symptoms, physical examination findings and hematologic variables in male and female HIV-seropositive injecting drug users (IDU) with similar CD4+ lymphocyte counts. METHOD: We interviewed and examined 118 female and 444 male AIDS-free HIV-seropositive IDU for clinical signs and symptoms. HIV serology and T-lymphocyte subset evaluations were performed. Comparisons were analyzed by Mantel-Haenszel procedures. RESULTS: In this population, median age for men was 35 years versus 33 years for women; median CD4 cell count was 490 x 10(6)/l for men versus 480 x 10(6)/l for women. The overall frequency of oral candidiasis increased as CD4 cell count decreased, but did not vary by sex. Recent history of genital herpes was more frequent (P < 0.05) in women than men, but this difference was not significant on physical examination. Symptoms of diarrhea, fatigue, weight loss, shortness of breath, presence of enlarged posterior cervical lymph nodes did not vary by CD4 cell count or sex, and no strong interactions were evident. Although absolute values of hematocrit were higher (P < 0.001) and platelet count lower (P < 0.001) in HIV-seropositive men than women, distributions of hematocrit and platelet count by sex were similar for HIV-seropositive participants and HIV-seronegative controls. CONCLUSION: Our data on IDU prior to a diagnosis of AIDS suggest that constitutional signs and symptoms are generally similar among men and women early in HIV infection. Additional follow-up is needed to determine whether differential rates of signs and symptoms by sex appear with progression of HIV infection.
AIDS-Related Opportunistic Infections↗
The incidence of HIV-1 infections in village populations of northern Thailand.
OBJECTIVES: To determine the age- and sex-specific prevalence of HIV-1 infection in a general ambulatory population in northern Thailand in 1990 and 1992, and the incidence of HIV-1 infections between 1990 and 1992. DESIGN: Health fairs were held in five villages in Chiang Mai province in northern Thailand between December 1989 and January 1990 and again in January 1992. Participation of all village residents was encouraged. Villagers were offered testing for serological markers of hepatitis B virus (HBV) infection and free HBV vaccine was made available to susceptible individuals. METHODS: Sera from the two surveys were linked and coded by demographic characteristics (age group and sex). Individual identifiers were removed and the sera tested for HIV-1 antibodies by enzyme-linked immunosorbent assay with Western blot confirmation. RESULTS: In 1990, 21 out of 1161 (1.8%) individuals were HIV-1-seropositive; the infection rates were 3.3% in men and 0.5% in women. In 1992, 44 out of 956 (4.6%) individuals were HIV-1-seropositive. Among people included in both surveys the 2-year incidence was 2.0% in women and 4.1% in men (annual incidence, 1.0 and 2.05%, respectively); however, among men over the age of 14 years the 2-year incidence was 6.3%, whereas among women of this age the 2-year incidence was 1.8% (annual incidence, 3.15 and 0.9%, respectively). Among men, incident HIV-1 infections were common, even among those aged 50 years or more. CONCLUSIONS: Infections with HIV-1 are disturbingly frequent and increasing among adult populations in semi-rural areas of northern Thailand. In order to contain further spread of the epidemic public-health strategies targeted to the general public, including those in rural areas, will be needed.
Adolescent↗
The epidemiology of HIV infection among injecting drug users and other risk populations in Thailand.
Explore the source record for details and available documents.
HIV Infections↗
Drug-related behavior change for HIV transmission among American injection drug users.
While high risk drug-related behaviors for human immunodeficiency virus (HIV) transmission among injection drug users (IDUs) are asserted to have declined over time in response to the AIDS epidemic, evidence from longitudinal cohorts has been sparse. In a cohort of 810 IDUs (442 seronegatives and 368 seropositives) in Baltimore, we identified drug-related risk behaviors at four consecutive semi-annual visits. Using robust methods for repeated measurements and multiple logistic regression, we estimated the probabilities of maintaining and reducing risk behaviors according to HIV serostatus and time in the study. Seropositive participants were more likely to maintain lower risk behaviors, and behavior maintenance increased with time in study for both seronegative and seropositive IDUs. Greater risk reduction (towards non-use and not sharing injection equipment) was seen among seropositive IDUs, with behavior change occurring soon after enrollment in the study. While behavior changes have been reported, many active IDUs, especially those still at risk for acquiring HIV infection, have not adequately reduced their risk. Continuing prevention programs and efforts in vaccine development are imperative to reduce the risk of HIV infection among IDUs.
Baltimore↗
Drug smoking, Pneumocystis carinii pneumonia, and immunosuppression increase risk of bacterial pneumonia in human immunodeficiency virus-seropositive injection drug users.
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).
AIDS-Related Opportunistic Infections↗
The trading of sex for drugs or money and HIV seropositivity among female intravenous drug users.
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.
Adult↗
Preparations for AIDS vaccine trials. Incident human immunodeficiency virus (HIV) infections in a cohort of injection drug users in Baltimore, Maryland.
In order to prepare for a possible trial of a preventive human immunodeficiency virus (HIV) vaccine in a population of injection drug users (IDUs) we followed a cohort to determine their HIV incidence, compliance with follow-up visits at 3-month intervals (i.e., quarterly) and their attitudes toward HIV vaccine trial participation. A population of 671 HIV-seronegative subjects were recruited from a cohort of IDUs already in follow-up in Baltimore, MD (the ALIVE study). We detected 19 seroconverters in 1677.80 person-quarters of follow-up, an annual incidence of 4.52/100 person-years. Compliance with quarterly follow-up was 93% at 6 months and 89% at 9 months. Although many subjects (n = 104) are not yet due for their 12-month visit, compliance to date has been 76%. The most sensitive risk behaviors associated with HIV seroconversion have been continued injection of illicit drugs and the frequency of drug use. Other reported drug associated risk behaviors, e.g., needle sharing and shooting gallery use, have decreased despite a high HIV incidence; we believe some of the reported reductions in high-risk behavior represent socially desirable responses by the study subjects. Although the difficulties in successfully doing a trial of an HIV vaccine in the population should not be underestimated, our data suggest that such a trial would be feasible.
AIDS Vaccines↗
Preparatory studies for possible HIV vaccine trials in northern Thailand.
We studied several populations of human immunodeficiency virus (HIV)-seronegative individuals from northern Thailand who were believed to be at relatively high risk of HIV infection in order to assess their potential suitability for inclusion in a preventive HIV vaccine trial. Included were female commercial sex workers (CSWs), male sexually transmitted disease (STD) clinic patients, male conscripts into the Royal Thai Army (RTA), and men who were recently discharged from the army. We evaluated their HIV prevalence, their interest in study participation, their compliance with prospective follow-up, and their HIV incidence. Among 1068 female CSWs the baseline HIV prevalence was 38.3%; of 659 HIV seronegatives 395 (59.9%) agreed to enrollment in the study. Follow-up at 6-9 months was 73.2%; it was 58% in brothel-based CSWs and 85% in non-brothel-based CSWs. Overall HIV incidence in CSWs was 8.2 per 100 person-years; incidence was 29 per 100 person-years in brothel-based CSWs and 4 per 100 person-years in non-brothel-based CSWs. Among 1031 male STD clinic patients, baseline HIV prevalence was 15.9%, follow-up was successful in 98.1%, and HIV incidence was 4.0 per 100 person-years. Among four cohorts of RTA conscripts who entered the military in 1991 and 1993, baseline HIV prevalence has been about 12%, follow-up about 90%, and HIV incidence has varied from 1.2-3.2 per 100 person-years. Discharged RTA conscripts have had baseline HIV prevalence of about 13%, successful follow-up of 94%, and an HIV incidence of about 5 per 100 person-years.(ABSTRACT TRUNCATED AT 250 WORDS)
AIDS Vaccines↗
Interest in HIV vaccines among injection drug users in Baltimore, Maryland.
To gauge interest about participation in human immunodeficiency virus type 1 (HIV vaccines, we interviewed 375 HIV-seronegative injecting drug users who are participants in an ongoing longitudinal study of HIV infection. Nearly all (93%) responded that they thought it likely that an HIV vaccine would become available, and 85% expressed interest in participating in a study of vaccine effectiveness. However, levels of interest decreased to 47% when respondents were informed that the vaccine might result in a positive HIV test and to 27% when offered to be in a study where the vaccine might contain a piece of the virus. Factors that increased interest in trial participation included assurances of confidentiality, being fully informed about the protocol and remuneration. Most respondents (78%) felt that injecting drug users would maintain other risk reduction activities (e.g., condom use) if they participated in a vaccine study. These data suggest a high level of interest for participation in HIV vaccine trials, but that more education about vaccines and the risks involved is needed. Ongoing communication with the community and responsiveness to community concerns is crucial to achieve a successful vaccine study.
AIDS Vaccines↗
Seroprevalence of HIV antibodies and risk factors in healthy young males from upper north Thailand.
In the Spring of 1991 a random sample of young men from Upper Northern Thailand (mean age = 21 years) was interviewed by trained medical students from Chiang Mai University, serum samples were obtained and analyzed for prevalence of HIV-1 antibodies and for syphilis, and risk factors for HIV infection were assessed. It was found that Commercial Sex Workers (CSW) were the principal risk factor, that consistent condom use is rare, and the rates of HIV infection are rising rapidly. Sociodemographic background, homosexual behavior, drug use, and history of STD's were found to be not significant risk factors. The conclusions are that the education campaigns should be intensified to reduce the frequency of contact with CSW and to encourage consistent use of condoms.
Adult↗
Field effectiveness of needle disinfection among injecting drug users.
To examine the putative protective effect of disinfectant use on HIV seroconversion among injecting drug users, we conducted a nested case-control study of black heterosexuals comparing 34 HIV seroconverters with 154 persistent seronegatives matched on gender, cocaine injection (yes/no), date of study entry, and duration of follow-up. Injecting drug users who reported using disinfectant all the time had an odds ratio of seroconversion of 0.87, as compared with those who reported no use of disinfectants; the corresponding odds ratio was 1.00 for those who used disinfectants less than all the time. We examined the effect of drug use and sex practice variables, and responses to a socially desirable responding scale as possible confounders for the effect of needle disinfection on HIV seroconversion; the adjusted odds ratios for disinfectant use and HIV seroconversion were unchanged in this analysis. Despite limited statistical power and the potential for residual confounding, these data suggest that disinfection of injection equipment is not a substitute for abstinence from drugs or use of sterile injection equipment.
1-Propanol↗
Risk factors for HIV infection among young adult men in northern Thailand.
OBJECTIVE: To determine the sociodemographic and behavioral risk factors associated with human immunodeficiency virus (HIV) infection in two cohorts of young men selected for military service in northern Thailand. DESIGN: Military conscripts were studied cross-sectionally after conscription in May 1991 and November 1991. Risk factors were assessed by interview with trained nonmilitary interviewers. SETTING: Two military training bases in Chiang Mai, Thailand. PARTICIPANTS: A total of 2417 young men aged 19 to 23 years (mean age, 21 years) conscripted by lottery into military service in the Royal Thai Army or Royal Thai Air Force from six provinces in northern Thailand. MAIN OUTCOME MEASURES: Human immunodeficiency virus seroprevalence by enzyme-linked immunosorbent assay confirmed by Western blot and univariate and multivariate analyses of sociodemographic and behavioral risk factors associated with HIV seroprevalence. RESULTS: Overall, 289 (12.0%) of 2417 men were HIV-seropositive at baseline. The strongest associations with being HIV positive were heterosexual activities. History of sex with a female commercial sex worker (CSW) was frequent (96.5% of men who were HIV-positive and 79.0% of men who were HIV-negative) and strongly associated with HIV infection on univariate and multivariate analyses (adjusted odds ratio, 1.60 to 2.07, depending on the frequency of CSW contact). Also, sexually transmitted diseases were common and associated with HIV infection in both univariate and multivariate analyses (adjusted odds ratio, 3.36). Sex with other males and injection drug use were uncommon and not associated with HIV infection. Condom use was reported in 61.5% of men at last sex with a CSW but was not shown to be protective of prevalent HIV infection. CONCLUSION: The epidemic of HIV infection has spread widely among young men in northern Thailand, despite reported frequent and recent use of condoms during sex with female CSWs. Control of HIV infection in this population will probably require more regular and effective use of condoms, prevention and treatment of sexually transmitted diseases, and reduction in the frequency of CSW contact.
Adult↗
Comparison of clinical symptoms of human immunodeficiency virus disease between intravenous drug users and homosexual men.
BACKGROUND: To compare the prevalence of human immunodeficiency virus (HIV)-related clinical symptoms among male intravenous drug users and homosexual men stratified by HIV serostatus and CD4 cell levels. METHODS: A cross-sectional sample using concurrent longitudinal studies of the natural history of HIV-1 infection among intravenous drug users (N = 539) and homosexual men (N = 932) was recruited in Baltimore, Md. Participants were administered a risk behavior interview and physical examination, and had hematologic tests evaluated in a similar calendar period. RESULTS: Both risk groups demonstrated an inverse relationship between frequency of symptoms and CD4 cell count. Fever, night sweats, and lymphadenopathy were not evaluated because pilot data suggested a confounding association with drug injection. Among those with mild to moderate immune suppression, intravenous drug users were significantly more likely than homosexual men to experience fatigue, weight loss, diarrhea, and shortness of breath; to have oral candidiasis, palpable spleen, and lower mean weight on physical examination; and abnormal hematocrit, platelets, and total lymphocyte counts. However, participants in either risk group with CD4 cell levels below 0.2 x 10(9)/L experienced similar frequency of all clinical symptoms. Self-reported oral candidiasis increased fourfold with HIV infection and was as likely in both groups at all CD4 cell levels. Duration and recency of intravenous drug use was not significantly associated with the higher frequency of most clinical symptoms. CONCLUSION: Social factors are an important consideration in evaluating the association between clinical symptoms and HIV immunosuppression. Except for oral candidiasis, there are limitations for the use of clinical symptoms as intermediate outcome measures for HIV infection among intravenous drug users.
Adult↗
Differences in risk factors for human immunodeficiency virus type 1 seroconversion among male and female intravenous drug users.
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.
Adult↗
Prevalence and incidence of hepatitis C virus infection among male prison inmates in Maryland.
To identify incidence of antibody to hepatitis C virus among 265 male prison inmates, we assayed paired serum specimens obtained at intake in 1985-1986 with follow-up specimens in 1987. Intake prevalence was 38 percent. Seroincidence was 1.1/100 person years in prison. This finding might reflect saturation of high-risk subgroups or possibly reduced frequency of exposures following incarceration.
Adult↗
Detection of human immunodeficiency virus type 1 infection by polymerase chain reaction in a cohort of seronegative intravenous drug users.
The frequency of serologically undetected human immunodeficiency virus type 1 (HIV-1) infection among a large cohort of seronegative intravenous drug users (IVDUs) was determined by polymerase chain reaction (PCR). In total, 2159 blood specimens were obtained from 945 seronegative IVDUs; of these, 182 had 1 specimen, 339 had 2, 397 had 3, and 27 had 4 semiannual specimens. No proviral DNA was detected in 2134 (98.8%) of the samples. Specimens from 7 persons (0.3%) were reactive by PCR. Within 6 months, all 5 of these 7 who returned for follow-up visits had seroconverted. Serum from 19 persons (0.9%) were equivocal by PCR analysis, that is, single primer pair amplification; 1 person seroconverted while others subsequently remained seronegative and nonreactive by PCR. The concordance between PCR and serology was 98.6%. It is concluded that immunosilent HIV-1 infection is uncommon and that serologic screening for HIV-1 antibodies is highly sensitive in this population.
Adolescent↗