Showing papers by "Irving F. Hoffman published in 2009"

Quantitating the Multiplicity of Infection with Human Immunodeficiency Virus Type 1 Subtype C Reveals a Non-Poisson Distribution of Transmitted Variants

Abstract: Identifying the specific genetic characteristics of successfully transmitted variants may prove central to the development of effective vaccine and microbicide interventions. Although human immunodeficiency virus transmission is associated with a population bottleneck, the extent to which different factors influence the diversity of transmitted viruses is unclear. We estimate here the number of transmitted variants in 69 heterosexual men and women with primary subtype C infections. From 1,505 env sequences obtained using a single genome amplification approach we show that 78% of infections involved single variant transmission and 22% involved multiple variant transmissions (median of 3). We found evidence for mutations selected for cytotoxic-T-lymphocyte or antibody escape and a high prevalence of recombination in individuals infected with multiple variants representing another potential escape pathway in these individuals. In a combined analysis of 171 subtype B and C transmission events, we found that infection with more than one variant does not follow a Poisson distribution, indicating that transmission of individual virions cannot be seen as independent events, each occurring with low probability. While most transmissions resulted from a single infectious unit, multiple variant transmissions represent a significant fraction of transmission events, suggesting that there may be important mechanistic differences between these groups that are not yet understood.

Epidemiology of Injuries at a Tertiary Care Center in Malawi

Abstract: Background Injury surveillance is an ongoing process required for primary, secondary, and tertiary injury prevention. In Malawi, hospital-based injury data are not available.

Drug choice, spatial distribution, HIV risk, and HIV prevalence among injection drug users in St. Petersburg, Russia.

Abstract: The HIV epidemic in Russia has been driven by the unsafe injection of drugs, predominantly heroin and the ephedrine derived psychostimulants. Understanding differences in HIV risk behaviors among injectors associated with different substances has important implications for prevention programs. We examined behaviors associated with HIV risk among 900 IDUs who inject heroin, psychostimulants, or multiple substances in 2002. Study participants completed screening questionnaires that provided data on sociodemographics, drug use, place of residence and injection- and sex-related HIV risk behaviors. HIV testing was performed and prevalence was modeled using general estimating equation (GEE) analysis. Individuals were clustered by neighborhood and disaggregated into three drug use categories: Heroin Only Users, Stimulant Only Users, and Mixed Drug Users. Among Heroin Only Users, younger age, front/backloading of syringes, sharing cotton and cookers were all significant predictors of HIV infection. In contrast, sharing needles and rinse water were significant among the Stimulant Only Users. The Mixed Drug Use group was similar to the Heroin Only Users with age, front/back loading, and sharing cotton significantly associated with HIV infection. These differences became apparent only when neighborhood of residence was included in models run using GEE. The type of drug injected was associated with distinct behavioral risks. Risks specific to Stimulant Only Users appeared related to direct syringe sharing. The risks specific to the other two groups are common to the process of sharing drugs in preparation to injecting. Across the board, IDUs could profit from prevention education that emphasizes both access to clean syringes and preparing and apportioning drug with these clean syringes. However, attention to neighborhood differences might improve the intervention impact for injectors who favor different drugs.

Predictors for mortality and loss to follow-up among children receiving anti-retroviral therapy in Lilongwe, Malawi.

Abstract: OBJECTIVES To determine predictors of mortality in children on anti-retroviral therapy (ART) who attended the Paediatric HIV Clinic at Kamuzu Central Hospital in Lilongwe, Malawi. METHODS Retrospective case cohort study by chart review of children who had started ART between October 2004 and May 2006. Bivariable and multivariable analysis were performed with and without defaulters to evaluate associations according to vital status and to identify independent predictors of mortality. RESULTS Forty-one of 258 children (15.9%) were deceased, 185 (71.7%) were alive, and 32 (12.4%) had defaulted: 51% were female, 7% were under 18 months, 26% were 18 months to 5 years, and 54% were >5 years of age. Most were WHO stage III or IV (56% and 37%, respectively). On multivariate analysis, factors most strongly associated with mortality and defaulting were age <18 months [hazards ratio (HR) 2.11 (95% CI 1.0-4.51)] and WHO stage IV [HR 2.00 (95% CI 1.07-3.76)]. CONCLUSIONS To improve outcomes of HIV-positive children, they must be identified and treated early, specifically children under 18 months of age. Access to infant diagnostic procedures must be improved to allow effective initiation of ART in infants at higher risk of death.

Correlates of Unsafe Equipment Sharing among Injecting Drug Users in St. Petersburg, Russia

Abstract: Aims: To assess among injecting drug users (IDUs) in St. Petersburg, Russia, the urban environment, social norms and individual correlates of unsafe injecting. Methods:<

Placental malaria and mother-to-child transmission of human immunodeficiency virus-1.

Abstract: There are few studies of the association between placental malaria (PM) and mother-to-child transmission (MTCT) of human immunodeficiency virus-1 (HIV-1), and the results of published studies are inconsistent. To determine the association between PM and MTCT of HIV-1, we performed a secondary analysis of data from a clinical trial of antibiotics to reduce chorioamnionitis. Data regarding 1,662 HIV-1-infected women with live born singleton and first-born twin infants with information regarding PM and infant HIV-1 infection status at birth were analyzed. At the time of the study, women did not have access to antiretroviral drugs for treatment of acquired immunodeficiency syndrome but had received nevirapine prophylaxis to reduce the risk of MTCT of HIV-1. Placental malaria was not associated with the infant HIV-1 infection status at birth (P = 0.67). Adjustment for maternal plasma viral load and CD4+ cell count did not change these results (odds ratio = 1.06, 95% confidence interval = 0.51-2.20, P = 0.87). Placental malaria was more likely to be related to HIV-1 infection at birth among women with low viral load at baseline (P for interaction = 0.08). In conclusion, PM was not associated with infant HIV-1 infection status at birth. The interaction of maternal plasma viral load, PM, and MTCT of HIV-1 warrants further studies.

Intrapartum antibiotic exposure and early neonatal, morbidity, and mortality in Africa.

Abstract: BACKGROUND: Infants born to women who receive intrapartum antibiotics may have higher rates of infectious morbidity and mortality than unexposed infants. OBJECTIVE: Our goal was to determine the association of maternal intrapartum antibiotics and early neonatal morbidity and mortality. METHODS: We performed secondary analysis of data from a multisite randomized placebo-controlled clinical trial of antibiotics to prevent chorioamnionitis-associated mother-to-child transmission of HIV-1 and preterm birth in sub-Saharan Africa. Early neonatal morbidity and mortality were analyzed. In an intention-to-treat (ITT) analysis infants born to women randomly assigned to antibiotics or placebo were compared. In addition non-ITT analysis was performed because some women received nonstudy antibiotics for various clinical indications. RESULTS: Overall 2659 pregnant women were randomly assigned. Of these 2466 HIV-1-infected and HIV-1-uninfected women delivered 2413 live born and 84 stillborn infants. In the ITT analysis there were no significant associations between exposure to antibiotics and early neonatal outcomes. Non-ITT analyses showed more illness at birth (11.2% vs 8.6% P = .03) and more admissions to the special care infant unit (12.6% vs 9.8% P = .04) among infants exposed to maternal intrapartum antibiotics than among unexposed infants. Additional analyses revealed greater early neonatal morbidity and mortality among infants of mothers who received nonstudy antibiotics than of mothers who received study antibiotics. CONCLUSIONS: There is no association between intrapartum exposure to antibiotics and early neonatal morbidity or mortality. The associations observed in non-ITT analyses are most likely the result of women with peripartum illnesses being more likely to receive nonstudy antibiotics.

Hypertension in pregnancy among HIV-infected women in sub-Saharan Africa: prevalence and infant outcomes.

Abstract: This analysis was performed to determine the prevalence of hypertension and association of MAP (mean arterial pressure) with birth outcomes among HIV-infected pregnant women not taking antiretrovirals. HIV-infected pregnant women, enrolled into the HPTN024 trial in Tanzania, Malawi and Zambia were followed up at 26-30, 36 weeks, and delivery. The prevalence of hypertension was <1% at both 20-24 weeks and 26-30 weeks and 1.7% by 36 weeks. A 5 mm Hg elevation in MAP increased the risk of stillbirth at 20-24 weeks by 29% (p=0.001), 32% (p=0.001) at 26-30 weeks and of low birth weight (LBW) at 36 weeks by 26% (p=0.001). MAP was not associated with stillbirth at 36 weeks, LBW prior to 36 weeks, preterm birth, neonatal mortality or the risk of maternal to child transmission (MTCT) of HIV (Afr J Reprod Health 2009; 13[4]:25-36).

Primary HIV-1 infection among infants in sub-Saharan Africa: HPTN 024.

Abstract: Our objectives were to assess clinical signs and diagnoses associated with primary HIV-1 infection among infants. We analyzed data from a clinical trial (HIV Prevention Trials Network Protocol 024) in sub-Saharan Africa. Study visits were conducted at birth, at 4-6 weeks, and at 3, 6, 9, and 12 months. The study population comprised live born, singleton, first-born infants of HIV-1-infected women with negative HIV-1 RNA assays who were still breastfeeding at 4-6 weeks. Of 1317 HIV-1-exposed infants, 84 became HIV-1 infected after 4-6 weeks and 1233 remained uninfected. There were 102 primary and 5650 nonprimary infection visits. The most common signs were cough and diarrhea, and the most common diagnoses were malaria and pneumonia. Primary infection was associated with significantly increased odds of diarrhea [odds ratio (OR) = 2.4], pneumonia (OR = 3.5), otitis media (OR = 3.1), and oral thrush (OR = 2.9). For the clinical signs and diagnoses evaluated, sensitivity was low (1%-16.7%) and specificity was high (88.2%-99%). Positive predictive values ranged from 0.1%-1.4%. Negative predictive values ranged from 28.0%-51.1%. Certain clinical signs and diagnoses, although more common during primary HIV-1 infection, had low sensitivity and high specificity. Efforts to expand access to laboratory assays for the diagnosis of primary HIV-1 infection among infants of HIV-1-infected women should be emphasized.