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Does oral vancomycin prophylaxis during systemic antibiotic exposure prevent Clostridioides difficile infection relapses? Still in search of an answer

Infect Control Hosp Epidemiol

2019 Liu, Catherine, MD Catherine Liu


Effect of Recombinant Zoster Vaccine on Incidence of Herpes Zoster After Autologous Stem Cell Transplantation: A Randomized Clinical Trial

Journal of the American Medical Association

2019 Boeckh, Michael J, MD, PhD Michael Boeckh

Importance: Herpes zoster, a frequent complication following autologous hematopoietic stem cell transplantation (HSCT), is associated with significant morbidity. A nonlive adjuvanted recombinant zoster vaccine has been developed to prevent posttransplantation zoster. Objective: To assess the efficacy and adverse event profile of the recombinant zoster vaccine in immunocompromised autologous HSCT recipients. Design, Setting, and Participants: Phase 3, randomized, observer-blinded study conducted in 167 centers in 28 countries between July 13, 2012, and February 1, 2017, among 1846 patients aged 18 years or older who had undergone recent autologous HSCT. Interventions: Participants were randomized to receive 2 doses of either recombinant zoster vaccine (n = 922) or placebo (n = 924) administered into the deltoid muscle; the first dose was given 50 to 70 days after transplantation and the second dose 1 to 2 months thereafter. Main Outcomes and Measures: The primary end point was occurrence of confirmed herpes zoster cases. Results: Among 1846 autologous HSCT recipients (mean age, 55 years; 688 [37%] women) who received 1 vaccine or placebo dose, 1735 (94%) received a second dose and 1366 (74%) completed the study. During the 21-month median follow-up, at least 1 herpes zoster episode was confirmed in 49 vaccine and 135 placebo recipients (incidence, 30 and 94 per 1000 person-years, respectively), an incidence rate ratio (IRR) of 0.32 (95% CI, 0.22-0.44; P < .001), equivalent to 68.2% vaccine efficacy. Of 8 secondary end points, 3 showed significant reductions in incidence of postherpetic neuralgia (vaccine, n=1; placebo, n=9; IRR, 0.1; 95% CI, 0.00-0.78; P = .02) and of other prespecified herpes zoster-related complications (vaccine, n=3; placebo, n=13; IRR, 0.22; 95% CI, 0.04-0.81; P = .02) and in duration of severe worst herpes zoster-associated pain (vaccine, 892.0 days; placebo, 6275.0 days; hazard ratio, 0.62; 95% CI, 0.42-0.89; P = .01). Five secondary objectives were descriptive. Injection site reactions were recorded in 86% of vaccine and 10% of placebo recipients, of which pain was the most common, occurring in 84% of vaccine recipients (grade 3: 11%). Unsolicited and serious adverse events, potentially immune-mediated diseases, and underlying disease relapses were similar between groups at all time points. Conclusions and Relevance: Among adults who had undergone autologous HSCT, a 2-dose course of recombinant zoster vaccine compared with placebo significantly reduced the incidence of herpes zoster over a median follow-up of 21 months. Trial Registration: Identifier: NCT01610414.

Simultaneous Inference of Treatment Effect Modification by Intermediate Response Endpoint Principal Strata with Application to Vaccine Trials

Int J Biostat

2019 Huang, Ying, PhD Ying Huang

In randomized clinical trials, researchers are often interested in identifying an inexpensive intermediate study endpoint (typically a biomarker) that is a strong effect modifier of the treatment effect on a longer-term clinical endpoint of interest. Motivated by randomized placebo-controlled preventive vaccine efficacy trials, within the principal stratification framework a pseudo-score type estimator has been proposed to estimate disease risks conditional on the counter-factual biomarker of interest under each treatment assignment to vaccine or placebo, yielding an estimator of biomarker conditional vaccine efficacy. This method can be used for trial designs that use baseline predictors of the biomarker and/or designs that vaccinate disease-free placebo recipients at the end of the trial. In this article, we utilize the pseudo-score estimator to estimate the biomarker conditional vaccine efficacy adjusting for baseline covariates. We also propose a perturbation resampling method for making simultaneous inference on conditional vaccine efficacy over the values of the biomarker. We illustrate our method with datasets from two phase 3 dengue vaccine efficacy trials.

Performance of cepheid GeneXpert HIV-1 viral load plasma assay to accurately detect treatment failure: a clinical meta-analysis


2019 Fong, Youyi, PhD Youyi Fong

BACKGROUND: Coverage of viral load testing remains low with only half of the patients in need having adequate access. Alternative technologies to high throughput centralized machines can be used to support viral load scale-up; however, clinical performance data are lacking. We conducted a meta-analysis comparing the Cepheid Xpert HIV-1 viral load plasma assay to traditional laboratory-based technologies. METHODS: Cepheid Xpert HIV-1 and comparator laboratory technology plasma viral load results were provided from 13 of the 19 eligible studies, which accounted for a total of 3790 paired data points. We used random effects models to determine the accuracy and misclassification at various treatment failure thresholds (detectable, 200, 400, 500, 600, 800 and 1000 copies/ml). RESULTS: Thirty percent of viral load test results were undetectable, while 45% were between detectable and 10 000 copies/ml and the remaining 25% were above 10 000 copies/ml. The median Xpert viral load was 119 copies/ml and the median comparator viral load was 157 copies/ml, while the log10 bias was 0.04 (0.02-0.07). The sensitivity and specificity to detect treatment failure were above 95% at all treatment failure thresholds, except for detectable, at which the sensitivity was 93.33% (95% confidence interval: 88.2-96.3) and specificity was 80.56% (95% CI: 64.6-90.4). CONCLUSION: The Cepheid Xpert HIV-1 viral load plasma assay results were highly comparable to laboratory-based technologies with limited bias and high sensitivity and specificity to detect treatment failure. Alternative specimen types and technologies that enable decentralized testing services can be considered to expand access to viral load.

Increasing PrEP uptake and adherence among MSM and TW sex workers in Lima, Peru: what and whom do different patients trust?


2019 Duerr, Ann C, MD, PhD Ann Duerr

In Peru, men who have sex with men (MSM) and transgender women (TW) suffer rates of HIV 50 times greater than the general population. MSM or TW sex workers (SWs) are at especially high risk. Daily oral pre-exposure prophylaxis (PrEP) effectively prevents HIV infection if patients adhere to a daily or on-demand regimen. Necessary levels of adoption and adherence require data-driven intervention strategies for these marginalized groups. We conducted qualitative content analysis of data obtained from focus groups (FGs) with MSM and TW SWs. Both groups expressed strong skepticism about the motives behind international drug trials, and the safety of participating in them. Important differences between MSM and TW groups' beliefs about trustworthy information as well as community and public institutions also emerged. MSM SWs were less trusting of information from other MSM SWs, and preferred to receive information from institutional medical sources, while TGW SWs preferred to receive information from other TGW SWs. Successful strategies to encourage PrEP uptake and adherence must address the distrust patients feel towards international and institutional actors by providing patients with tailored, reliable information from local and community sources that they trust.

Ethical considerations for new HIV prevention trials

Lancet HIV

2019 Donnell, Deborah J, PhD Deborah Donnell



J Virol

2019 Gilbert, Peter B, PhD Peter Gilbert

The RV144 vaccine trial is the only clinical study to have shown a modest but statistically significant decrease in HIV infection risk. RV144 and the subsequent studies identifying the level of V1V2-specific antibodies as a correlate of reduced infection risk are still controversial despite many papers supporting and expanding the initial study. We address these controversies and summarize active and passive immunization experiments in non-human primates that support the initial finding.

TRAILshort Protects against CD4 T Cell Death during Acute HIV Infection

J Immunol

2019 Kiem, Hans-Peter, MD, PhD Hans-Peter Kiem

CD4 T cells from HIV-1 infected patients die at excessive rates compared to those from uninfected patients, causing immunodeficiency. We previously identified a dominant negative ligand that antagonizes the TRAIL-dependent pathway of cell death, which we called TRAILshort. Because the TRAIL pathway has been implicated in CD4 T cell death occurring during HIV-1 infection, we used short hairpin RNA knockdown, CRISPR deletion, or Abs specific for TRAILshort to determine the effect of inhibiting TRAILshort on the outcome of experimental acute HIV infection in vitro. Strikingly, all three approaches to TRAILshort deletion/inhibition enhanced HIV-induced death of both infected and uninfected human CD4 T cells. Thus, TRAILshort impacts T cell dynamics during HIV infection, and inhibiting TRAILshort causes more HIV-infected and uninfected bystander cells to die. TRAILshort is, therefore, a host-derived, host-adaptive mechanism to limit the effects of TRAIL-induced cell death. Further studies on the effects of TRAILshort in other disease states are warranted.

Fc Characteristics Mediate Selective Placental Transfer of IgG in HIV-Infected Women


2019 Fong, Youyi, PhD Youyi Fong

The placental transfer of maternal IgG is critical for infant protection against infectious pathogens. However, factors that modulate the placental transfer of IgG remain largely undefined. HIV-infected women have impaired placental IgG transfer, presenting a unique "disruption model" to define factors that modulate placental IgG transfer. We measured the placental transfer efficiency of maternal HIV and pathogen-specific IgG in US and Malawian HIV-infected mothers and their HIV-exposed uninfected and infected infants. We examined the role of maternal HIV disease progression, infant factors, placental Fc receptor expression, IgG subclass, and glycan signatures and their association with placental IgG transfer efficiency. Maternal IgG characteristics, such as binding to placentally expressed Fc receptors FcgammaRIIa and FcgammaRIIIa, and Fc region glycan profiles were associated with placental IgG transfer efficiency. Our findings suggest that Fc region characteristics modulate the selective placental transfer of IgG, with implications for maternal vaccine design and infant health.

Therapeutic HSV-2 vaccine decreases recurrent virus shedding and recurrent genital herpes disease


2019 Wald, Anna, MD, MPH Anna Wald

BACKGROUND: Genital herpes simplex virus (HSV) type 2 is a common persistent infection that frequently reactivates to cause recurrent lesions and recurrent viral shedding which is incompletely controlled by antiviral therapy. GEN-003 is a candidate therapeutic vaccine containing 2 HSV-2 proteins, gD2 and ICP4, and Matrix-M2 adjuvant (M2). METHODS: HSV-2 seropositive persons with genital herpes were randomized into three dose cohorts of Gen-003 (60microg antigen/50microgM2, 60microg/75microgM2 or Placebo). Three intramuscular doses 21days apart of GEN-003 or placebo were administered. Participants obtained genital area swabs twice-daily for HSV-2 detection and monitored genital lesions for 12months. The rates of virus shedding and lesion rates before vaccination were compared to 3 defined periods after vaccination; Days 43-71, Month 6 and Month 12. RESULTS: GEN-003 at a dose of 60microg each antigen/50microgM2 reduced HSV shedding immediately after dosing with a rate ratio of 0.58, compared to 0.75 for the GEN-003 60microg/75microgM2 and 1.06 for placebo. Lesion rates, recurrence rates, and duration of recurrences were also reduced. Reactogenicity was higher with the 75microgM2 dose than the 50microgM2 dose, specifically for pain, tenderness, malaise and fatigue. Antibody and cellular immune responses were stimulated by both doses and persisted to 12months. CONCLUSIONS: GEN-003 vaccine manufactured with a scalable process gave results similar to those observed in prior clinical trials. GEN-003 had an acceptable safety profile and stimulated both humoral and cellular immune responses. The 60microg antigen/50microgM2 provided the maximal effect on virologic and clinical measures and warrants further development. (Funded by Genocea; number NCT02515175).