Higher T-Cell Responses Induced by DNA/rAd5 HIV-1 Preventive Vaccine Are Associated With Lower HIV-1 Infection Risk in an Efficacy Trial.

Background: It is important to identify vaccine-induced immune responses that predict the preventative efficacy of a human immunodeficiency virus (HIV)-1 vaccine. We assessed T-cell response markers as correlates of risk in the HIV Vaccine Trials Network (HVTN) 505 HIV-1 vaccine efficacy trial. Methods: 2504 participants were randomized to DNA/rAd5 vaccine or placebo, administered at weeks 0, 4, 8, and 24. Peripheral blood mononuclear cells were obtained at week 26 from all 25 primary endpoint vaccine cases and 125 matched vaccine controls, and stimulated with vaccine-insert-matched peptides. Primary variables were total HIV-1-specific CD4+ T-cell magnitude and Env-specific CD4+ polyfunctionality. Four secondary variables were also assessed. Immune responses were evaluated as predictors of HIV-1 infection among vaccinees using Cox proportional hazards models. Machine learning analyses identified immune response combinations best predicting HIV-1 infection. Results: We observed an unexpectedly strong inverse correlation between Env-specific CD8+ immune response magnitude and HIV-1 infection risk (hazard ratio [HR] = 0.18 per SD increment; P = .04) and between Env-specific CD8+ polyfunctionality and infection risk (HR = 0.34 per SD increment; P < .01). Conclusions: Further research is needed to determine if these immune responses are predictors of vaccine efficacy or markers of natural resistance to HIV-1 infection.

Testing the waters: Ethical considerations for including PrEP in a phase IIb HIV vaccine efficacy trial.

BACKGROUND: The field of HIV prevention research has recently experienced some mixed results in efficacy trials of pre-exposure prophylaxis, vaginal microbicides, and HIV vaccines. While there have been positive trial results in some studies, in the near term, no single method will be sufficient to quell the epidemic. Improved HIV prevention methods, choices among methods, and coverage for all at-risk populations will be needed. The emergence of partially effective prevention methods that are not uniformly available raises complex ethical and scientific questions regarding the design of ongoing prevention trials. METHODS: We present here an ethical analysis regarding inclusion of pre-exposure prophylaxis in an ongoing phase IIb vaccine efficacy trial, HVTN 505. This is the first large vaccine efficacy trial to address the issue of pre-exposure prophylaxis, and the decisions made by the protocol team were informed by extensive stakeholder consultations. The key ethical concerns are analyzed here, and the process of stakeholder engagement and decision-making described. DISCUSSION: This discussion and analysis will be useful as current and future research teams grapple with ethical and scientific study design questions emerging with the rapidly expanding evidence base for HIV prevention.

Ethical considerations in HIV prevention and vaccine research in resource-limited settings.

HIV prevention research has been facing increasing ethical and operational challenges. Factors influencing the design and conduct of HIV prevention trials include a rapidly changing evidence base, new biomedical prevention methods and modalities being tested, a large diversity of countries, sites and populations affected by HIV and participating in trials, and challenges of developing and making available products that will be feasible and affordable for at-risk populations. To discuss these challenges, a meeting, Ethical considerations around novel combination prevention modalities in HIV prevention and vaccine trials in resource-limited settings, was convened by NIH/NIAID/Division of AIDS on April 22-23, 2013. Several themes emerged from the meeting: (1) because of both trial design and ethical complexities, choosing prevention packages and designing combination prevention research trials will need to be evaluated on a case by case basis in different clinical trials, countries, and health systems; (2) multilevel stakeholder engagement from the beginning is vital to a fair and transparent process and also to designing ethical and relevant trials; (3) research should generally be responsive to a host country's needs, and sponsors and stakeholders should work together to address potential barriers to future access; and finally, (4) another meeting including a broader group of stakeholders is needed to address many of the outstanding ethical issues raised by this meeting. We offer an overview of the meeting and the key discussion points and recommendations to help guide the design and conduct of future HIV prevention and vaccine research in resource-limited settings.

Efficacy trial of a DNA/rAd5 HIV-1 preventive vaccine.

BACKGROUND: A safe and effective vaccine for the prevention of human immunodeficiency virus type 1 (HIV-1) infection is a global priority. We tested the efficacy of a DNA prime-recombinant adenovirus type 5 boost (DNA/rAd5) vaccine regimen in persons at increased risk for HIV-1 infection in the United States. METHODS: At 21 sites, we randomly assigned 2504 men or transgender women who have sex with men to receive the DNA/rAd5 vaccine (1253 participants) or placebo (1251 participants). We assessed HIV-1 acquisition from week 28 through month 24 (termed week 28+ infection), viral-load set point (mean plasma HIV-1 RNA level 10 to 20 weeks after diagnosis), and safety. The 6-plasmid DNA vaccine (expressing clade B Gag, Pol, and Nef and Env proteins from clades A, B, and C) was administered at weeks 0, 4, and 8. The rAd5 vector boost (expressing clade B Gag-Pol fusion protein and Env glycoproteins from clades A, B, and C) was administered at week 24. RESULTS: In April 2013, the data and safety monitoring board recommended halting vaccinations for lack of efficacy. The primary analysis showed that week 28+ infection had been diagnosed in 27 participants in the vaccine group and 21 in the placebo group (vaccine efficacy, -25.0%; 95% confidence interval, -121.2 to 29.3; P=0.44), with mean viral-load set points of 4.46 and 4.47 HIV-1 RNA log10 copies per milliliter, respectively. Analysis of all infections during the study period (41 in the vaccine group and 31 in the placebo group) also showed lack of vaccine efficacy (P=0.28). The vaccine regimen had an acceptable side-effect profile. CONCLUSIONS: The DNA/rAd5 vaccine regimen did not reduce either the rate of HIV-1 acquisition or the viral-load set point in the population studied. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT00865566.).

Immuno-virologic outcomes and immuno-virologic discordance among adults alive and on anti-retroviral therapy at 12 months in Nigeria.

BACKGROUND: Predictors of immuno-virologic outcomes and discordance and their associations with clinical, demographic, socio-economic and behavioral risk factors are not well described in Nigeria since HIV viral load testing is not routinely offered in public HIV treatment programs. METHODS: The HACART study was a multi-center observational clinic-based cohort study of 2585 adults who started HAART between April 2008 and February 2009. A total of 628 patients were randomly selected at 12 months for immuno-virologic analyses. RESULTS: Virologic suppression rate (<400 copies/ml) was 76.7%, immunologic recovery rate (CD4 change from baseline ≥50 cells/mm3) was 77.4% and immuno-virologic discordance rate was 33%. In multivariate logistic regression, virologic failure was associated with age <30 years (OR 1.79; 95% CI: 1.17-2.67, p=0.03), anemia (Hemoglobin < 10 g/dl) (OR 1.71; 95% CI: 1.22-2.61, p=0.03), poor adherence (OR 3.82; 95% CI: 2.17-5.97, p=0.001), and post-secondary education (OR 0.60; 95% CI: 0.30-0.86, p=0.02). Immunologic failure was associated with male gender (OR 1.46; 95% CI: 1.04-2.45, p=0.04), and age <30 years (OR 1.50; 95% CI: 1.11-2.39, p=0.03). Virologic failure with immunologic success (VL-/CD4+) was associated with anemia (OR 1.80; 95% CI: 1.13-2.88, p=0.03), poor adherence (OR 3.90; 95% CI: 1.92-8.24, p=0.001), and post-secondary education (OR 0.40; 95% CI: 0.22-0.68, p=0.005). CONCLUSIONS: Although favorable immuno-virologic outcomes could be achieved in this large ART program, immuno-virologic discordance was observed in a third of the patients. Focusing on intensified treatment preparation and adherence, young patients, males, persons with low educational status and most importantly baseline anemia assessment and management may help address predictors of poor immuno-virologic outcomes, and improve overall HIV program impact. Viral load testing in addition to the CD4 testing should be considered to identify, characterize and address negative immuno-virologic outcomes and discordance.

Current status and future prospects of epidemiology and public health training and research in the WHO African region.

BACKGROUND: To date little has been published about epidemiology and public health capacity (training, research, funding, human resources) in WHO/AFRO to help guide future planning by various stakeholders. METHODS: A bibliometric analysis was performed to identify published epidemiological research. Information about epidemiology and public health training, current research and challenges was collected from key informants using a standardized questionnaire. RESULTS: From 1991 to 2010, epidemiology and public health research output in the WHO/AFRO region increased from 172 to 1086 peer-reviewed articles per annum [annual percentage change (APC) = 10.1%, P for trend < 0.001]. The most common topics were HIV/AIDS (11.3%), malaria (8.6%) and tuberculosis (7.1%). Similarly, numbers of first authors (APC = 7.3%, P for trend < 0.001), corresponding authors (APC = 8.4%, P for trend < 0.001) and last authors (APC = 8.5%, P for trend < 0.001) from Africa increased during the same period. However, an overwhelming majority of respondents (>90%) reported that this increase is only rarely linked to regional post-graduate training programmes in epidemiology. South Africa leads in publications (1978/8835, 22.4%), followed by Kenya (851/8835, 9.6%), Nigeria (758/8835, 8.6%), Tanzania (549/8835, 6.2%) and Uganda (428/8835, 4.8%) (P < 0.001, each vs South Africa). Independent predictors of relevant research productivity were 'in-country numbers of epidemiology or public health programmes' [incidence rate ratio (IRR) = 3.41; 95% confidence interval (CI) 1.90-6.11; P = 0.03] and 'number of HIV/AIDS patients' (IRR = 1.30; 95% CI 1.02-1.66; P < 0.001). CONCLUSIONS: Since 1991, there has been increasing epidemiological research productivity in WHO/AFRO that is associated with the number of epidemiology programmes and burden of HIV/AIDS cases. More capacity building and training initiatives in epidemiology are required to promote research and address the public health challenges facing the continent.

Standardizing surveillance of pneumococcal disease.

BACKGROUND: Surveillance for invasive pneumococcal disease has been conducted using a variety of case ascertainment methods and diagnostic tools. Interstudy differences in observed rates of invasive pneumococcal disease could reflect variations in surveillance methods or true epidemiological differences in disease incidence. To facilitate comparisons of surveillance data among countries, investigators of Pneumococcal Vaccines Accelerated Development and Introduction Plan-sponsored projects have developed standard case definitions and data reporting methods. METHODS: Investigators developed case definitions for meningitis, pneumonia, and very severe disease using existing World Health Organization guidelines and clinical definitions from Africa and Asia. Standardized case definitions were used to standardize reporting of aggregated results. Univariate analyses were conducted to compare results among countries and to identify factors contributing to detection of Streptococcus pneumoniae. RESULTS: Surveillance sites varied with regard to the age groups targeted, disease syndromes monitored, specimens collected, and laboratory methods employed. The proportion of specimens positive for pneumococcus was greater for cerebrospinal fluid specimens (1.2%-19.4%) than for blood specimens (0.1%-1.4%) in all countries (range, 1.3-38-fold greater). The distribution of disease syndromes and pneumonia severity captured by surveillance differed among countries. The proportion of disease cases with pneumococcus detected varied by syndrome (meningitis, 1.4%-10.8%; pneumonia, 0.2%-1.3%; other, 0.2%-1.2%) and illness severity (nonsevere pneumonia, 0%-2.7%; severe pneumonia, 0.2%-1.2%), although these variations were not consistent for all sites. Antigen testing and polymerase chain reaction increased the proportion of cerebrospinal fluid specimens with pneumococcus identified by 1.3-5.5-fold, compared with culture alone. CONCLUSIONS: Standardized case definitions and data reporting enhanced our understanding of pneumococcal epidemiology and enabled us to assess the contributions of specimen type, disease syndrome, pneumonia severity, and diagnostic tools to rate of pneumococcal detection. Broader standardization and more-detailed data reporting would further improve interpretation of surveillance results.