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Biomedical subjects

D Vlahov

Publications and source records attributed to D Vlahov.

At least 199 records · Page 11Linked to original sources
PubMed1996

Viral infections in short-term injection drug users: the prevalence of the hepatitis C, hepatitis B, human immunodeficiency, and human T-lymphotropic viruses.

OBJECTIVES: The purpose of this study was to estimate the prevalence and correlates of four blood-borne viral infections among illicit drug injectors with up to 6 years of injecting experience. METHODS: We analyzed data from 716 volunteers recruited in 1988 and 1989. Test results for hepatitis C virus (HCV), hepatitis B virus (HBV), human immunodeficiency virus, type 1 (HIV), and human T-lymphotropic virus types I and II (HTLV) were examined across six sequential cohorts defined by duration of drug injection. RESULTS: Overall, seroprevalence of HCV, HBV, HIV, and HTLV was 76.9%, 65.7%, 20.5% and 1.8%, respectively, and 64.7%, 49.8%, 13.9%, and 0.5%, respectively, among those who had injected for 1 year or less. Among the newest initiates, HCV and HBV were associated with injecting variables, and HIV was associated with sexual variables. CONCLUSIONS: The high rates of HCV, HBV, and HIV infections among short-term injectors emphasizes the need to target both parenteral and sexual risk reduction interventions early. Renewed efforts at primary prevention of substance abuse are indicated.

Adolescent↗
PubMed1995

Medical eligibility, comprehension of the consent process, and retention of injection drug users recruited for an HIV vaccine trial.

Injection drug users (IDUs) at high risk for human immunodeficiency virus (HIV) infection are being identified as a population for HIV vaccine trials. We studied willingness of drug users to enroll and their comprehension of consent procedures in the context of a Phase II trial at one site. Of 175 people screened for enrollment and whose data sets were complete, 119 (68%) were IDUs. Of the 71 who were eligible, 39 (55%) were IDUs. Exclusion of IDUs was usually for medical reasons. Using a 17-item true/false test, comprehension of the informed consent procedure was high (median score, 16 of 17 for IDUs and non-IDUs); only three subjects (all of whom were IDUs) were excluded from enrollment due to lack of comprehension. Follow-up rates were similar for IDUs and non-IDUs. These data suggest that recruitment of IDUs into HIV vaccine trials is feasible, that IDUs can comprehend and complete the informed consent procedures, and that they return for follow-up visits.

AIDS Vaccines↗
PubMed1995

Instability of delayed-type hypersensitivity skin test anergy in human immunodeficiency virus infection.

OBJECTIVE: To evaluate stability of delayed-type hypersensitivity (DTH) skin test over time in human immunodeficiency virus (HIV)-seropositive and HIV-seronegative injecting drug users. METHOD: A community-based cohort of injecting drug users who had serial skin testing with purified protein derivative tuberculin, mumps, and Candida albicans antigen. Delayed-type hypersensitivity anergy was defined as a skin test result of less than 3 mm for all three antigens; DTH positivity was a skin test result of 3 mm or greater for at least one antigen (Centers for Disease Control and Prevention, Atlanta, Ga, 1993). RESULTS: At baseline, 36% of HIV-seropositive subjects (n = 401) were anergic as compared with 14% of HIV-seronegative subjects (n = 552; P < .001). During follow-up, fewer HIV-seropositive subjects remained DTH positive (42%) and more remained anergic (19%) than of HIV-seronegative subjects (67% and 7%, respectively). Twenty-four percent of HIV-seropositive subjects who were initially DTH positive became anergic as compared with 15.3% of the HIV-seronegative subjects. However, the proportion changing from anergy to DTH positivity was greater among HIV-seropositive subjects (15%) than HIV-seronegative subjects (12%). In comparison to those who remained DTH positive, HIV-seropositive subjects with CD4 cell counts of less than 0.50 x 10(9)/L (odds ratio = 6.4) and less than 0.35 x 10(9)/L (odds ratio = 11.2) were more likely to remain anergic than those who had CD4 cell counts above 0.50 x 10(9)/L or were HIV seronegative. CONCLUSIONS: Although the prevalence and incidence of DTH anergy were higher in HIV-seropositive subjects, high rates of change in DTH status occurred in both directions. This suggests that instability of DTH skin testing is substantial and only partially dependent on HIV status. Although a single test may be an unreliable indicator of HIV-induced immunosuppression, two consecutive anergic readings were strongly associated with a CD4 cell count below 0.50 x 10(9)/L and particularly below 0.35 x 10(9)/L. For determining false negativity of tuberculin tests, persistent DTH anergy is more reliable than a single test among HIV-seropositive injecting drug users. Anergy testing appears to be unnecessary with CD4 cell counts greater than 0.5 x 10(9)/L.

Adult↗
PubMed1995

Acquisition and use of needles and syringes by injecting drug users in Baltimore, Maryland.

Our objective was to determine how injection drug users (IDUs) in Baltimore, Maryland obtain and use needles and syringes (NS) for drug injection, before the opening of a needle exchange program (NEP). The method of this study was a cross-sectional structured interview survey in 1992 of active IDUs in a longitudinal study of human immunodeficiency virus (HIV) infection. For 466 IDUs (94.6% black, 83% male), usual sources of NS were "street" dealers (49.6%), pharmacies (29.8%), diabetics (16.3%), friends/neighbors (2.2%), and "shooting galleries" (1.9%). Half (53.5%) reported pharmacy purchase of NS, and 55.6% had diabetic friends/relatives. Twenty-three percent traded drugs, and 5% traded sex for NS. Eighty-eight and two-tenths percent would use a needle exchange program; 24.6% currently own no NS (median owned = 2.2). NS reuse was common (median = three times). Concern about (55.2%) or history of (33.9%) hassle/arrest for NS possession was typical; 81% kept NS at home, and 67% do not carry NS when purchasing drugs. Pharmacy purchasers (versus "street") were less likely to have been jailed, shared NS, or used shooting galleries during the preceding 6 months. In Maryland, although IDUs can legally purchase NS at pharmacist discretion, possession remains illegal; fewer than one-third of IDUs use pharmacies, and most obtain NS from illegal sources. Most IDUs reuse NS, but discard them after several uses. Current patterns of NS acquisition and use in Baltimore are likely to increase HIV transmission. Increased availability and decriminalization of NS possession could decrease the risk of injection-related HIV transmission.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Seroepidemiology of hepatitis B virus in a population of injecting drug users. Association with drug injection patterns.

To investigate the epidemiology of hepatitis B virus (HBV) infection among injecting drug users, the authors assessed the prevalence of HBV seromarkers among 2,558 injecting drug users recruited through street outreach in Baltimore, Maryland, in 1988-1989. Eighty percent of the drug users had at least one HBV seromarker. HBV seropositivity was associated with increasing age, duration of injecting drug use, African-American ethnicity, injecting drugs at least once daily, and sharing needles or visiting "shooting galleries" during the previous 11 years, but not with high-risk sexual behaviors or a history of sexually transmitted disease. This finding is possibly due to the relative inefficiency of sexual transmission as compared with parenteral transmission in injecting drug users. In addition, HBV seropositivity was strongly associated with seropositivity for hepatitis C virus and human immunodeficiency virus. The authors conclude that HBV transmission among injecting drug users occurs primarily through the sharing of contaminated drug injecting equipment rather than through sexual relations, and that efforts to prevent HBV infection must target injecting drug users early in their injecting careers.

Adult↗
PubMed1995

Recent infection with human immunodeficiency virus and possible rapid loss of CD4 T lymphocytes.

To assess a hypothesized trend that persons recently infected with the human immunodeficiency virus (HIV) may have more rapid declines in absolute CD4 T-lymphocyte (CD4+ cell) counts than those who were HIV-infected in earlier years, sequential CD4+ cell counts in three groups who had definable dates of HIV seroconversion between 1978 and 1992 were reviewed. The CD4+ cell counts examined were from some of the longest extant studies in the United States: 100 homosexual and bisexual men engaged in ongoing observational cohort studies in San Francisco, Denver, and Chicago since 1978 (Group 1); 89 persons in South Carolina infected after 1986 (Group 2); and 155 injecting drug users participating in an observational cohort study in Baltimore since 1988 (Group 3). For all groups, individually and in the aggregate, mean CD4+ cell counts declined rapidly in the first year after HIV infection and then stabilized. However, there was no clear trend for lower (or higher) CD4+ cell counts by fixed time after HIV seroconversion among those seroconverting in recent compared with earlier calendar years. These data do not support a hypothesized trend for more rapid loss of CD4 T lymphocytes--and, by implication, more pathogenic strains of HIV-1--among persons acquiring HIV infection in recent years.

CD4 Lymphocyte Count↗
PubMed1995

Temporal trends of incident human immunodeficiency virus infection in a cohort of injecting drug users in Baltimore, Md.

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.

Adult↗
PubMed1995

Incidence and risk factors for human T-lymphotropic virus type II seroconversion among injecting drug users in Baltimore, Maryland, U.S.A.

To determine the incidence of and risk factors for human T-lymphotropic virus, type II (HTLV-II) seroconversion among injecting drug users (IDUs), specimens from IDUs recruited into the ALIVE Study in 1988/1989 were assayed at baseline for antibody to HTLV with use of enzyme immunoassay and Western blot. Participants were monitored semiannually with venipuncture and interviews. In 1992, the most recent sera of HTLV-negative participants were tested for HTLV with use of enzyme immunoassay and confirmed and typed by Western blot. For positive cases, assays were then performed for all intervening visits to determine the calendar time of seroconversion. Incidence rates were estimated using person-time. Risk factor analysis used a nested case-control design, with up to seven controls per case matched by time of study entry and duration of follow-up. At baseline, 251 HTLV-positive, 22 indeterminate, and 2,574 HTLV-seronegative IDUs were identified. Follow-up of the seronegative IDUs identified 38 seroconverters (all HTLV-II) over 5,813.6 person-years, for a rate of 0.7/100 person-years. Median lag time for seroconversion was 6.8 months. Factors associated with HTLV-II seroconversion included a specific needle-sharing practice called "backloading" within the previous 6 months [odds ratio (OR) = 6.52; 95% confidence interval (CI) = 1.94-21.95] and a baseline history of receiving money for sex (OR = 3.36; 95% CI = 1.32-8.57). Of those with more than one sex partner in the past 6 months, women were more likely than men to seroconvert (OR = 5.77; 95% CI = 1.33-25.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Changes in markers of disease progression in HIV-1 seroconverters: a comparison between cohorts of injecting drug users and homosexual men.

Comparisons of human immunodeficiency virus (HIV) disease progression between risk groups are difficult primarily because of the long incubation period of acquired immune deficiency syndrome (AIDS) and unknown times of infection. This is believed to be the first study that directly compared changes in T-lymphocyte subsets following HIV-1 seroconversion between cohorts of predominantly black injecting drug users and predominantly white homosexual men. Longitudinal trends of CD4 and CD8 percentages of total lymphocytes during 4 years were modeled as piecewise linear functions with a two-parameter correlation structure to accommodate within-person repeated observations. Prior to seroconversion the 151 injecting drug users started with similar CD4% and CD8% levels compared with the 99 homosexual men. Following seroconversion, larger changes were observed overall in the homosexual men compared with the injecting drug users for both markers (p < or = 0.001). The major discrepancies, however, were limited to the first 2 years. Subsequently, the CD4% levels of the two cohorts converged and then declined at similar rates. These comparative analyses of HIV seroconverters in homosexual men and injecting drug users suggest that risk group has only a minor effect on the initial course of HIV infection.

Adult↗
PubMed1995

Compliance with universal precautions among health care workers at three regional hospitals.

OBJECTIVE: To assess and characterize self-reported levels of compliance with universal precautions among hospital-based health care workers and to determine correlates of compliance. DESIGN: Confidential questionnaire survey of 1716 hospital-based health care workers. PARTICIPANTS: Participants were recruited from three geographically distinct hospitals. A stratified convenience sample of physicians, nurses, technicians, and phlebotomists working in emergency, surgery, critical care, and laboratory departments was selected from employment lists to receive the survey instrument. All participants had direct contact with either patients or patient specimens. RESULTS: For this study, overall compliance was defined as "always" or "often" adhering to the desired protective behavior. Eleven different items composed the overall compliance scale. Compliance rates varied among the 11 items, from extremely high for certain activities (e.g., glove use, 97%; disposal of sharps, 95%) to low for others (e.g., wearing protective outer clothing, 62%; wearing eye protection, 63%). Compliance was strongly correlated with several key factors: (1) perceived organizational commitment to safety, (2) perceived conflict of interest between workers' need to protect themselves and their need to provide medical care to patients; (3) risk-taking personality; (4) perception of risk; (5) knowledge regarding routes of HIV transmission; and (6) training in universal precautions. Compliance rates were associated with some demographic characteristics: female workers had higher overall compliance scores than did male workers (25% of female and 19% of male respondents circled "always" or "often" on each of the 11 items, p < 0.05); and overall compliance scores were highest for nurses, intermediate for technicians, and lowest for physicians. Overall compliance scores were higher for the mid-Atlantic respondents (28%) than for those from the Southwest (20%) or Midwest (20%, p = 0.001). CONCLUSIONS: This study supports earlier findings regarding several compliance correlates (perception of risk, knowledge of universal precautions), but it also identifies important new variables, such as the organizational safety climate and perceived conflict of interest. Several modifiable variables were identified, and intervention programs that address as many of these factors as possible will probably succeed in facilitating employee compliance.

Blood-Borne Pathogens↗
PubMed1995

Using social network analysis to study patterns of drug use among urban drug users at high risk for HIV/AIDS.

Few studies have examined the current social relationships of injecting drug users. This paper examines the structural and relationship characteristics of the social networks of injecting drug users, and the relation of social network characteristics to the HIV infection risk behavior of frequency of injecting heroin and cocaine. The study sample was comprised of 293 inner city injecting drug users in Baltimore, Maryland. Most participants (89%) reported at least one family member in their social network, and 44% listed their mother or step-mother in their network. Presence of family members in personal social networks was not related to patterns of drug use examined here; however, those who reported a partner in their personal social network injected significantly less often than those who did not report a partner. Network density and size of drug subnetworks were positively associated with frequency of drug injection. The results of this study suggest that social network analysis may be a useful tool for understanding the social context of HIV/AIDS risk behaviors.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Occupational risk of human immunodeficiency virus, hepatitis B virus, and hepatitis C virus infections among funeral service practitioners in Maryland.

OBJECTIVE: To estimate the risk of exposure and infection with bloodborne pathogens, a seroepidemiologic survey was conducted among funeral service practitioners (FSPs) in Maryland. METHOD: Of 262 members of the Maryland State Funeral Directors Association, 130 (49%) volunteered to participate in the study. In addition to a brief questionnaire, designed to assess both occupational and non-occupational risk factors for bloodborne pathogen infection, participants were screened for markers of human immunodeficiency virus (HIV), hepatitis C virus (HCV), and past hepatitis B virus (HBV). Titers for antibodies to hepatitis B surface antigen (anti-HBs) also were examined and compared with history of hepatitis B vaccination. RESULTS: Seroprevalence for HIV, HBV, and HCV infection was 0.8%, 4.6%, and 0%, respectively. Nearly 19% of participants reported at least one bloodborne exposure in the past 6 months. The one HIV infection and all but two of the HBV infections were correlated with well-established non-occupational risk behaviors. Disposable gloves were worn by 96%, and eating, drinking, or smoking during embalming were infrequent. Sixty-one percent of FSPs reported having received one or more doses of hepatitis B vaccine at some time in the past. Of those who reported having received all three doses of vaccine, 67% had adequate titers to hepatitis B surface antibody, the marker of protection related to vaccination. CONCLUSION: Compared with prior studies of FSPs, this study found a low rate of occupational exposures and a high rate of hepatitis B vaccination, suggesting improved compliance with recommendations for preventing transmission of bloodborne pathogens in the workplace.

Funeral Rites↗
PubMed1995

Dilated heart muscle disease associated with HIV infection.

As more effective therapies have produced longer survival times for HIV-infected patients, non-infectious complications of late stage HIV infection such as the development of severe global left ventricular dysfunction (dilated heart muscle disease) have emerged. The demographic and clinical characteristics of HIV-infected patients who develop dilated heart muscle disease as well as potential risk factors are, as yet, poorly characterized. Of 174 patients enrolled in a prospective longitudinal study, a total of nine patients, all with CD4 T cell counts < 200 mm-3, developed symptomatic heart disease (congestive heart failure n = 7, sudden cardiac death n = 1 and cardiac tamponade n = 1); three of these patients developed progressive cardiac dysfunction leading to primary cardiac failure and death. An additional 55 HIV-infected patients referred to our Cardiomyopathy Service were found to have global left ventricular dysfunction, with 84% having New York Heart Association Class III or IV congestive heart failure on presentation. Clinical characteristics associated with severe symptomatic cardiac dysfunction included low CD4 T cell counts, myocarditis associated with non-permissive cardiotropic virus infection on endomyocardial biopsy and persistent elevation of anti-heart antibodies. No relationships to any specific HIV risk factor or opportunistic infection were found. These findings suggest that a severe form of HIV-related dilated heart muscle disease is largely a disease of late stage HIV infection. Virus-related myocarditis and cardiac autoimmunity may play a role in the pathogenesis of progressive cardiac injury. Long-term longitudinal studies of larger HIV-infected cohorts are warranted to identify clinical, behavioral and immunologic risk factors.

Adult↗
PubMed1995

Human immunodeficiency virus type 1 env and p17gag sequence variation in polymerase chain reaction-positive, seronegative injection drug users.

Variation in gene sequences from human immunodeficiency virus type 1 (HIV-1) p17gag and the third hypervariable region (V3 loop) of env was examined in a cross-sectional study of single specimens from 4 HIV-1 polymerase chain reaction-positive, seronegative injection drug users. As observed in sexually transmitted disease, clones of HIV-1 genes isolated from an individual were remarkably homogeneous, with amino acid variation in the envelope region of 0.3%-0.9% and in p17gag of 0.0%-0.7%. Intersubject variation was much greater (at the amino acid level, 15% for the envelope and 4.3% for p17gag), with conservation in the envelope only of regions at the base of the V3 loop. Since at least some subjects likely acquired infection intravenously, the ability of virus to survive in seminal fluid or on mucosal surfaces cannot explain the observed homogeneity, which may depend on direct interactions between the virus and the infected cell.

Amino Acid Sequence↗
PubMed1995

Identification of human immunodeficiency virus primary isolates resistant to interferon-alpha and correlation of prevalence to disease progression.

Human immunodeficiency virus (HIV) primary isolates, derived from donors at various stages of HIV infection, were assayed for their sensitivity to interferon (IFN)-alpha 2 in vitro. These isolates displayed a broad range of sensitivity to IFN-alpha 2. The prevalence of IFN-alpha 2 resistance was low in the absence of AIDS but dramatically increased once HIV infection progressed to AIDS. Although there was no linear correlation between the percentage of IFN-alpha 2 inhibition in vitro and the CD4 cell number in vivo or the level of endogenous IFN-alpha, serum IFN-alpha levels were higher in donors with AIDS and were associated with low CD4 cell numbers. Thus, circulating IFN-alpha appeared to either promote resistance or favor survival of IFN-alpha resistant variants. IFN-alpha 2 resistance was neither limited to a particular cell tropism nor enhanced by therapy with zidovudine. Sequential analysis indicated that reversion to IFN-alpha 2 sensitivity could occur during the course of infection.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Vitamin A deficiency and wasting as predictors of mortality in human immunodeficiency virus-infected injection drug users.

A nested case-control study of vitamin A deficiency and wasting as risk factors for mortality from AIDS and infections was done within a large prospective cohort of human immunodeficiency virus (HIV)-infected injection drug users (IDUs). Fifty adult subjects who died from AIDS and infections were matched with 235 controls who survived. Plasma vitamin A, weight, and body mass index were measured. Mean length of follow-up was 2.4 +/- 1.1 years. Vitamin A deficiency occurred in 50% and wasting occurred in 38% of patients in the last visit before death. CD4 cells count < 200/microL, wasting, and vitamin A deficiency were associated with mortality. There was a higher risk of death in HIV-infected subjects with vitamin A deficiency (odds ratio [OR], 4.6; 95% confidence interval [CI], 1.8-11.3) and wasting (OR, 8.8; 95% CI, 2.7-28.2). Vitamin A deficiency and wasting are common during HIV infection and are independent predictors of mortality in HIV-infected IDUs.

Acquired Immunodeficiency Syndrome↗