Browsing by Author "Gray, Glenda"

Now showing 1 - 6 of 6
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    Enrolling adolescents in HIV vaccine trials: reflections on legal complexities from South Africa
    (BioMed Central Ltd, 2007) Slack, Catherine; Strode, Ann; Fleischer, Theodore; Gray, Glenda; Ranchod, Chitra
    BACKGROUND:South Africa is likely to be the first country in the world to host an adolescent HIV vaccine trial. Adolescents may be enrolled in late 2007. In the development and review of adolescent HIV vaccine trial protocols there are many complexities to consider, and much work to be done if these important trials are to become a reality.DISCUSSION:This article sets out essential requirements for the lawful conduct of adolescent research in South Africa including compliance with consent requirements, child protection laws, and processes for the ethical and regulatory approval of research.SUMMARY:This article outlines likely complexities for researchers and research ethics committees, including determining that trial interventions meet current risk standards for child research. Explicit recommendations are made for role-players in other jurisdictions who may also be planning such trials. This article concludes with concrete steps for implementing these important trials in South Africa and other jurisdictions, including planning for consent processes; delineating privacy rights; compiling information necessary for ethics committees to assess risks to child participants; training trial site staff to recognize when disclosures trig mandatory reporting response; networking among relevant ethics commitees; and lobbying the National Regulatory Authority for guidance.
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    Optimal uses of antiretrovirals for prevention in HIV-1 serodiscordant heterosexual couples in South Africa: a modelling study
    (Public Library of Science, 2011) Hallett, Timothy B; Baeten, Jared M; Heffron, Renee; Barnabas, Ruanne; De Bruyn, Guy; Cremin, Íde; Delany, Sinead; Garnett, Geoffrey P; Gray, Glenda; Johnson, Leigh
    Hallett et al use a mathematical model to examine the long-term impact and cost-effectiveness of different pre-exposure prophylaxis (PrEP) strategies for HIV prevention in serodiscordant couples.
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    A phase IIA randomized clinical trial of a multiclade HIV-1 DNA prime followed by a multiclade rAd5 HIV-1 vaccine boost in healthy adults (HVTN204)
    (Public Library of Science, 2011) Churchyard, Gavin J; Morgan, Cecilia; Adams, Elizabeth; Hural, John; Graham, Barney S; Moodie, Zoe; Grove, Doug; Gray, Glenda; Bekker, Linda-Gail; McElrath, M Juliana
    BACKGROUND: The safety and immunogenicity of a vaccine regimen consisting of a 6-plasmid HIV-1 DNA prime (envA, envB, envC, gagB, polB, nefB) boosted by a recombinant adenovirus serotype-5 (rAd5) HIV-1 with matching inserts was evaluated in HIV-seronegative participants from South Africa, United States, Latin America and the Caribbean. METHODS: 480 participants were evenly randomized to receive either: DNA (4 mg IM by Biojector) at 0, 1 and 2 months, followed by rAd5 (10 10 PU IM by needle/syringe) at 6 months; or placebo. Participants were monitored for reactogenicity and adverse events throughout the 12-month study. Peak and duration of HIV-specific humoral and cellular immune responses were evaluated after the prime and boost. RESULTS: The vaccine was well tolerated and safe. T-cell responses, detected by interferon-γ (IFN-γ) ELISpot to global potential T-cell epitopes (PTEs) were observed in 70.8% (136/192) of vaccine recipients overall, most frequently to Gag (54.7%) and to Env (54.2%). In U.S. vaccine recipients T-cell responses were less frequent in Ad5 sero-positive versus sero-negative vaccine recipients (62.5% versus 85.7% respectively, p = 0.035). The frequency of HIV-specific CD4+ and CD8+ T-cell responses detected by intracellular cytokine staining were similar (41.8% and 47.2% respectively) and most secreted ≥2 cytokines. The vaccine induced a high frequency (83.7%-94.6%) of binding antibody responses to consensus Group M, and Clades A, B and C gp140 Env oligomers. Antibody responses to Gag were elicited in 46% of vaccine recipients. CONCLUSION: The vaccine regimen was well-tolerated and induced polyfunctional CD4+ and CD8+ T-cells and multi-clade anti-Env binding antibodies. Trial Registration: ClinicalTrials.gov NCT00125970
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    Predictors of HVTN 503 MRK-AD5 HIV-1 gag/pol/nef vaccine Induced immune responses
    (Public Library of Science, 2014) Hopkins, Kathryn L; Laher, Fatima; Otwombe, Kennedy; Churchyard, Gavin; Bekker, Linda-Gail; DeRosa, Stephen; Nchabeleng, Maphoshane; Mlisana, Koleka; Kublin, James; Gray, Glenda
    BACKGROUND: Phambili, the Merck (MRK)-Adenovirus Type 5 (Ad5) HIV-1 gag/pol/nef subtype B vaccine study, conducted in South Africa, suspended enrollment and vaccination when companion study, Step, was found non-efficacious. Although the vaccine did not prevent HIV-1 infection or lower viral-load setpoint, immune responses recognized clades B and C HIV-1 subtypes. We investigated predictors of the vaccine-induced antigen-specific immune responses. METHODS: Vaccine-induced immunogenicity was ascertained by interferon-γ ELISpot assays on the first 186 enrolled participants receiving two vaccinations. Analyses, stratified by study arm/sex, were performed on baseline demographics [sex, age, Body Mass Index (BMI), site, Adenovirus Type-5 (Ad5) titer, Herpes Simplex Virus Type-2 (HSV2) status, heavy drinking]. Multivariate logistic regression determined predictors. RESULTS: Of the 186 participants, 53.7% (n = 100) were female, median BMI was 22.5 [IQR: 20.4-27.0], 85.5% (n = 159) were Ad5 seropositive, and 18.8% (n = 35) drank heavily. All vaccine recipients responded to both clade B (n = 87; 47%) and/or C (n = 74; 40%), p = 0.17. In multivariate analysis, female sex [Adjusted Odds Ratio (AOR): 6.478; p = 0.0159], overweight/obese BMI (AOR: 0.186; p = 0.0452), and heavy drinking (AOR: 0.270; p = 0.048) significantly predicted immune response to clade C for any antigens. A marginally significant predictor of clade C-pol antigen was female sex (AOR: 3.182; p = 0.0500). CONCLUSIONS: Sex, BMI, and heavy drinking affected vaccine-induced HIV-1 specific immune responses to clade C antigens. The role of female sex and overweight/obese BMI boosting and suppressing vaccine-induced HIV-1 specific immune responses, respectively, requires elucidation, including any effect on HIV vaccine efficacy, especially in the era of colliding epidemics (HIV and obesity).
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    Sequential Immunization with gp140 boosts immune responses primed by modified vaccinia Ankara or DNA in HIV-uninfected South African participants
    (Public Library of Science, 2016) Churchyard, Gavin; Mlisana, Koleka; Karuna, Shelly; Williamson, Anna-Lise; Williamson, Carolyn; Morris, Lynn; Tomaras, Georgia D; De Rosa, Stephen C; Gilbert, Peter B; Gu, Niya; Yu, Chenchen; Mkhize, Nonhlanhla N; Hermanus, Tandile; Allen, Mary; Pensiero, Michael; Barnett, Susan W; Gray, Glenda; Bekker, Linda-Gail; Montefiori, David C; Kublin, James; Corey, Lawrence
    BACKGROUND: The safety and immunogenicity of SAAVI DNA-C2 (4 mg IM), SAAVI MVA-C (2.9 x 10 9 pfu IM) and Novartis V2-deleted subtype C gp140 (100 mcg) with MF59 adjuvant in various vaccination regimens was evaluated in HIV-uninfected adults in South Africa. METHODS: Participants at three South African sites were randomized (1:1:1:1) to one of four vaccine regimens: MVA prime, sequential gp140 protein boost (M/M/P/P); concurrent MVA/gp140 (MP/MP); DNA prime, sequential MVA boost (D/D/M/M); DNA prime, concurrent MVA/gp140 boost (D/D/MP/MP) or placebo. Peak HIV specific humoral and cellular responses were measured. RESULTS: 184 participants were enrolled: 52% were female, all were Black/African, median age was 23 years (range, 18-42 years) and 79% completed all vaccinations. 159 participants reported at least one adverse event, 92.5% were mild or moderate. Five, unrelated, serious adverse events were reported. The M/M/P/P and D/D/MP/MP regimens induced the strongest peak neutralizing and binding antibody responses and the greatest CD4+ T-cell responses to Env. All peak neutralizing and binding antibody responses decayed with time. The MVA, but not DNA, prime contributed to the humoral and cellular immune responses. The D/D/M/M regimen was poorly immunogenic overall but did induce modest CD4+ T-cell responses to Gag and Pol. CD8+ T-cell responses to any antigen were low for all regimens. CONCLUSIONS: The SAAVI DNA-C2, SAAVI MVA-C and Novartis gp140 with MF59 adjuvant in various combinations were safe and induced neutralizing and binding antibodies and cellular immune responses. Sequential immunization with gp140 boosted immune responses primed by MVA or DNA. The best overall immune responses were seen with the M/M/P/P regimen. Trial Registration ClinicalTrials.gov NCT01418235
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    Uptake of genital mucosal sampling in HVTN 097, a phase 1b HIV vaccine trial in South Africa
    (Public Library of Science, 2014) Lazarus, Erica Maxine; Otwombe, Kennedy; Adonis, Tania; Sebastian, Elaine; Gray, Glenda; Grunenberg, Nicole; Roux, Surita; Churchyard, Gavin; Innes, Craig; Laher, Fatima
    Because sexual transmission of HIV occurs across mucosal membranes, understanding the immune responses of the genital mucosa to vaccines may contribute knowledge to finding an effective candidate HIV vaccine. We describe the uptake of rectal secretion, cervical secretion and seminal mucosal secretion sampling amongst volunteers in a Phase 1b HIV vaccine trial. Age at screening, gender, study site and the designation of the person conducting the informed consent procedure were collected for volunteers who screened for the HVTN 097 study. A total of 211 volunteers (54% female) were screened at three sites in South Africa: Soweto (n = 70, 33%), Cape Town (n = 68, 32%) and Klerksdorp (n = 73, 35%). Overall uptake of optional mucosal sampling amongst trial volunteers was 71% (n = 149). Compared to Cape Town, volunteers from Soweto and Klerksdorp were less likely to consent to sampling (Soweto OR 0.08 CI: 0.03-0.25 p<0.001 and Klerksdorp OR 0.13 CI: 0.04-0.41 p = 0.001). In contrast, volunteers over 25 years of age were 2.39 times more likely to consent than younger volunteers (CI: 1.13-5.08, p = 0.02). Further studies are required to better understand the cultural, demographic and sociobehavioral factors which influence willingness to participate in mucosal sampling in HIV prevention studies. Trial Registration ClinicalTrials.gov: NCT02109354