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1.
AIDS Behav ; 21(5): 1361-1375, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-27317411

RESUMEN

Placebo-controlled trials of pre-exposure prophylaxis (PrEP) have reported challenges with study-product uptake and use, with the greatest challenges reported in studies with young women in sub-Saharan Africa. We conducted a qualitative sub-study to explore experiences with open-label PrEP among young women in Cape Town, South Africa participating in HTPN 067/Alternative Dosing to Augment Pre-Exposure Prophylaxis Pill Taking (ADAPT). HPTN 067/ADAPT provided open label oral FTC/TDF PrEP to young women in Cape Town, South Africa who were randomized to daily and non-daily PrEP regimens. Following completion of study participation, women were invited into a qualitative sub-study including focus groups and in-depth interviews. Interviews and groups followed a semi-structured guide, were recorded, transcribed, and translated to English from isiXhosa, and coded using framework analysis. Sixty of the 179 women enrolled in HPTN 067/ADAPT participated in either a focus group (six groups for a total of 42 participants) or an in-depth interview (n = 18). This sample of mostly young, unmarried women identified facilitators of and barriers to PrEP use, as well as factors influencing study participation. Cross-cutting themes characterizing discourse suggested that women placed high value on contributing to the well-being of one's community (Ubuntu), experienced a degree of skepticism towards PrEP and the study more generally, and reported a wide range of approaches towards PrEP (ranging from active avoidance to high levels of persistence and adherence). A Mutuality Framework is proposed that identifies four dynamics (distrust, uncertainty, alignment, and mutuality) that represent distinct interactions between self, community and study and serve to contextualize women's experiences. Implications for better understanding PrEP use, and non-use, and intervention opportunities are discussed. In this sample of women, PrEP use in the context of an open-label research trial was heavily influenced by underlying beliefs about safety, reciprocity of contributions to community, and trust in transparency and integrity of the research. Greater attention to factors positioning women in the different dynamics of the proposed Mutuality Framework could direct intervention approaches in clinical trials, as well as open-label PrEP scale-up.


Asunto(s)
Fármacos Anti-VIH/administración & dosificación , Infecciones por VIH/prevención & control , Cumplimiento de la Medicación , Aceptación de la Atención de Salud/psicología , Profilaxis Pre-Exposición/métodos , Estigma Social , Adulto , Femenino , Grupos Focales , Humanos , Entrevistas como Asunto , Evaluación de Programas y Proyectos de Salud , Investigación Cualitativa , Sudáfrica , Adulto Joven
2.
Ann Intern Med ; 164(5): 313-22, 2016 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-26833336

RESUMEN

BACKGROUND: A prophylactic HIV-1 vaccine is a global health priority. OBJECTIVE: To assess a novel vaccine platform as a prophylactic HIV-1 regimen. DESIGN: Randomized, double-blind, placebo-controlled trial. Both participants and study personnel were blinded to treatment allocation. (ClinicalTrials.gov: NCT01215149). SETTING: United States, East Africa, and South Africa. PATIENTS: Healthy adults without HIV infection. INTERVENTION: 2 HIV-1 vaccines (adenovirus serotype 26 with an HIV-1 envelope A insert [Ad26.EnvA] and adenovirus serotype 35 with an HIV-1 envelope A insert [Ad35.Env], both administered at a dose of 5 × 1010 viral particles) in homologous and heterologous combinations. MEASUREMENTS: Safety and immunogenicity and the effect of baseline vector immunity. RESULTS: 217 participants received at least 1 vaccination, and 210 (>96%) completed follow-up. No vaccine-associated serious adverse events occurred. All regimens were generally well-tolerated. All regimens elicited humoral and cellular immune responses in nearly all participants. Preexisting Ad26- or Ad35-neutralizing antibody titers had no effect on vaccine safety and little effect on immunogenicity. In both homologous and heterologous regimens, the second vaccination significantly increased EnvA antibody titers (approximately 20-fold from the median enzyme-linked immunosorbent assay titers of 30-300 to 3000). The heterologous regimen of Ad26-Ad35 elicited significantly higher EnvA antibody titers than Ad35-Ad26. T-cell responses were modest and lower in East Africa than in South Africa and the United States. LIMITATIONS: Because the 2 envelope inserts were not identical, the boosting responses were complex to interpret. Durability of the immune responses elicited beyond 1 year is unknown. CONCLUSION: Both vaccines elicited significant immune responses in all populations. Baseline vector immunity did not significantly affect responses. Second vaccinations in all regimens significantly boosted EnvA antibody titers, although vaccine order in the heterologous regimen had a modest effect on the immune response. PRIMARY FUNDING SOURCE: International AIDS Vaccine Initiative, National Institutes of Health, Ragon Institute, Crucell Holland.


Asunto(s)
Vacunas contra el SIDA/efectos adversos , Vacunas contra el SIDA/inmunología , Infecciones por VIH/prevención & control , VIH-1 , Adenoviridae , Adolescente , Adulto , África Oriental , Formación de Anticuerpos , Método Doble Ciego , Ensayo de Inmunoadsorción Enzimática , Femenino , Vectores Genéticos , VIH-1/inmunología , Humanos , Inmunidad Celular , Inmunidad Humoral , Masculino , Persona de Mediana Edad , Sudáfrica , Estados Unidos , Adulto Joven
3.
AIDS Care ; 24(10): 1277-89, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22452384

RESUMEN

Standards of care provided to volunteers in HIV prevention research in developing countries are evolving. Inconsistency in standards, particularly within a research network highlights the need to balance volunteers' health and wellness with the efficient conduct of research. Ten research centers (RC's) in East and Southern Africa affiliated with the International AIDS Vaccine Initiative (IAVI) were studied using a mixed methods approach to understand variations, similarities and gaps in services provided, recipients of services, referral systems, and barriers to referral uptake. These data were then used to develop expected standards across the 10 RCs. Findings indicated that RCs consistently provided HIV risk reduction and family planning (FP) counseling, male condoms, management of sexually transmitted infections, CD-4 counts, and general medical care to volunteers and non-research volunteers. Services that were less consistently provided on-site included: female condoms, adult male circumcision (AMC), antiretroviral therapy (ART) and post-exposure prophylaxis (PEP) in case of rape. The FP options provided on-site varied, with few providing implants, intrauterine devices, tubal ligation, and vasectomy. Most RCs had established referral systems for ART, AMC, PEP, and FP, but few had referral points for psychosocial services. Few RCs had comprehensive guidelines on referrals other than those related to adverse events. Findings indicate that the greatest challenges for referral uptake were transportation and health care costs, poor quality and inconsistency of services at some referral points. Few RCs covered the cost of referrals for non-study related adverse events. A collaborative process between IAVI and the RCs was undertaken to reach consensus on expected standards of care. A set of required and recommended services to be provided on-site or by referral was developed. In developing such standards, we tried to balance scientific priorities, equity, contextual realities, community expectations, and cost-effectiveness.


Asunto(s)
Consejo/normas , Servicios de Planificación Familiar/normas , Infecciones por VIH/epidemiología , Investigación sobre Servicios de Salud/organización & administración , Aceptación de la Atención de Salud/estadística & datos numéricos , Nivel de Atención/estadística & datos numéricos , África Oriental/epidemiología , África Austral/epidemiología , Recuento de Linfocito CD4 , Estudios de Casos y Controles , Atención a la Salud , Femenino , Infecciones por VIH/tratamiento farmacológico , Humanos , Masculino , Conducta de Reducción del Riesgo
4.
Thorax ; 66(2): 134-9, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21098802

RESUMEN

BACKGROUND: The incidence of tuberculosis has increased among South African gold miners despite comprehensive control programmes, including a radiological screening programme. No data are available as to the optimal frequency of screening. The aim of this study was to compare 6-monthly and 12-monthly radiological screening for active tuberculosis case-finding. METHODS: Employees of a gold mining company were randomly assigned to the control arm (screening at baseline, 12 and 24 months) or the intervention arm (additional 'intervention' radiographs at 6 and 18 months after baseline). Study outcomes included proportion of tuberculosis cases detected by screening, proportion smear-positive, extent of disease and mortality. RESULTS: 22,634 miners were randomised. Compared with 12-monthly screening, 6-monthly screening detected more tuberculosis suspects but not more cases, partly due to greater attrition between screening and further investigation after 'intervention' compared with routine radiographs. Tuberculosis cases detected in the 6-monthly versus the 12-monthly screening arm had less extensive disease (p=0.05) and a lower tuberculosis-specific mortality (death on tuberculosis treatment) (2.1 and 2.8 per 1000 person-years respectively, HR 0.73, 95% CI 0.50 to 1.08, p=0.1), which was most marked in the first 2 months of treatment (HR 0.48, 95% CI 0.23 to 0.98, p=0.04) when death from tuberculosis is most likely. DISCUSSION: In settings with a high prevalence of HIV and tuberculosis despite standard tuberculosis control measures, more frequent case-finding may reduce the extent of disease, tuberculosis mortality and tuberculosis transmission through earlier detection of active tuberculosis cases. To be effective, however, all tuberculosis suspects identified through screening must be investigated for tuberculosis.


Asunto(s)
Radiografías Pulmonares Masivas/métodos , Tuberculosis Pulmonar/diagnóstico por imagen , Adulto , Diagnóstico Precoz , Oro , Humanos , Masculino , Minería , Mycobacterium tuberculosis/aislamiento & purificación , Sudáfrica/epidemiología , Esputo/microbiología , Factores de Tiempo , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/epidemiología
5.
Pediatrics ; 147(1)2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33386332

RESUMEN

BACKGROUND AND OBJECTIVES: Human papillomavirus (HPV) antibody responses to the 9-valent human papillomavirus (9vHPV) vaccine among girls and boys (aged 9-14 years) receiving 2-dose regimens (months 0, 6 or 0, 12) were noninferior to a 3-dose regimen (months 0, 2, 6) in young women (aged 16-26 years) 4 weeks after last vaccination in an international, randomized, open-label trial (NCT01984697). We assessed response durability through month 36. METHODS: Girls received 2 (months 0 and 6 [0, 6]: n = 301; months 0 and 12 [0, 12]: n = 151) or 3 doses (months 0,2, and 6 [0, 2, 6]: n = 301); boys received 2 doses ([0, 6]: n = 301; [0, 12]: n = 150); and young women received 3 doses ([0, 2, 6]: n = 314) of 9vHPV vaccine. Anti-HPV geometric mean titers (GMTs) were assessed by competitive Luminex immunoassay (cLIA) and immunoglobulin G-Luminex immunoassay (IgG-LIA) through month 36. RESULTS: Anti-HPV GMTs were highest 1 month after the last 9vHPV vaccine regimen dose, decreased sharply during the subsequent 12 months, and then decreased more slowly. GMTs 2 to 2.5 years after the last regimen dose in girls and boys given 2 doses were generally similar to or greater than GMTs in young women given 3 doses. Across HPV types, most boys and girls who received 2 doses (cLIA: 81%-100%; IgG-LIA: 91%-100%) and young women who received 3 doses (cLIA: 78%-98%; IgG-LIA: 91%-100%) remained seropositive 2 to 2.5 years after the last regimen dose. CONCLUSIONS: Antibody responses persisted through 2 to 2.5 years after the last dose of a 2-dose 9vHPV vaccine regimen in girls and boys. In girls and boys, antibody responses generated by 2 doses administered 6 to 12 months apart may be sufficient to induce high-level protective efficacy through at least 2 years after the second dose.


Asunto(s)
Alphapapillomavirus/inmunología , Anticuerpos Antivirales/sangre , Vacunas contra Papillomavirus/administración & dosificación , Adolescente , Adulto , Biomarcadores/sangre , Niño , Relación Dosis-Respuesta Inmunológica , Femenino , Estudios de Seguimiento , Humanos , Masculino , Vacunas contra Papillomavirus/inmunología , Adulto Joven
6.
Sci Transl Med ; 11(510)2019 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-31534016

RESUMEN

One of the most successful HIV vaccines to date, the RV144 vaccine tested in Thailand, demonstrated correlates of protection including cross-clade V1V2 immunoglobulin G (IgG) breadth, Env-specific CD4+ T cell polyfunctionality, and antibody-dependent cellular cytotoxicity (ADCC) in vaccinees with low IgA binding. The HIV Vaccine Trials Network (HVTN) 097 trial evaluated this vaccine regimen in South Africa, where clade C HIV-1 predominates. We compared cellular and humoral responses at peak and durability immunogenicity time points in HVTN 097 and RV144 vaccinee samples, and evaluated vaccine-matched and cross-clade immune responses. At peak immunogenicity, HVTN 097 vaccinees exhibited significantly higher cellular and humoral immune responses than RV144 vaccinees. CD4+ T cell responses were more frequent in HVTN 097 irrespective of age and sex, and CD4+ T cell Env-specific functionality scores were higher in HVTN 097. Env-specific CD40L+ CD4+ T cells were more common in HVTN 097, with individuals having this pattern of expression demonstrating higher median antibody responses to HIV-1 Env. IgG and IgG3 binding antibody rates and response magnitude to gp120 vaccine- and V1V2 vaccine-matched antigens were higher or comparable in HVTN 097 than in RV144 ADCC, and ADCP functional antibody responses were elicited in HVTN 097. Env-specific IgG and CD4+ Env responses declined significantly over time in both trials. Overall, cross-clade immune responses associated with protection were better than expected in South Africa, suggesting wider applicability of this regimen.


Asunto(s)
Vacunas contra el SIDA/inmunología , Adulto , Formación de Anticuerpos/inmunología , Citotoxicidad Celular Dependiente de Anticuerpos/inmunología , Ligando de CD40/metabolismo , Femenino , Anticuerpos Anti-VIH/inmunología , Antígenos VIH/inmunología , Humanos , Inmunidad Humoral , Inmunoglobulina G/inmunología , Interferón gamma/metabolismo , Interleucina-2/metabolismo , Masculino , Pruebas de Neutralización , Fagocitosis , Placebos , Análisis de Componente Principal , Sudáfrica , Linfocitos T/inmunología , Tailandia , Vacunación , Adulto Joven
7.
Lancet HIV ; 5(2): e68-e78, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-28986029

RESUMEN

BACKGROUND: The relative feasibility and acceptability of daily versus non-daily dosing of oral HIV pre-exposure prophylaxis (PrEP) among women are unknown. We aimed to investigate the feasibility of non-daily PrEP regimens in adult women. METHODS: We did a randomised, open-label, phase 2 clinical trial (HPTN 067/ADAPT) of oral PrEP with emtricitabine plus tenofovir disoproxil fumarate at a research centre in Cape Town, South Africa. Participants were adult women (age ≥18 years) who received directly observed dosing once a week for 5 weeks followed by random assignment (1:1:1) at week 6 to one of three unblinded PrEP regimens for self-administered dosing over 24 weeks: daily; time-driven (twice a week plus a post-sex dose); or event-driven (one tablet both before and after sex). Primary outcomes were PrEP coverage (at least one dose within the 4 days before sex and one dose within 24 h after sex), pills needed or used to achieve regimen-specific adherence and coverage, and symptoms and side-effects. All analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01327651; the trial is completed and this report presents the final analysis. FINDINGS: Between Sept 12, 2011, and Oct 3, 2012, 191 women were enrolled to the trial. 178 (93%) completed directly observed dosing and were randomly assigned one of the three PrEP regimens for the self-administered phase: 59 were allocated the daily regimen, 59 the time-driven regimen, and 60 the event-driven regimen. Median age of women was 26 years (IQR 21-37; range 18-52). In women allocated the daily regimen, 1459 (75%) of 1952 sex events were covered by PrEP, compared with 599 (56%) of 1074 sex events among those assigned the time-driven regimen (odds ratio [OR] 2·35, 95% CI 1·43-3·83; p=0·0007) and 798 (52%) of 1542 sex events among those allotted the event-driven regimen (2·76, 1·68-4·53; p<0·0001). Fewer pills were needed for complete adherence in women allocated non-daily regimens (vs daily regimen, relative mean 2·53 [95% CI 2·39-2·69] for the time-driven regimen and 4·16 [3·59-4·82] for the event-driven regimen; p<0·0001). Side-effects were uncommon. Eight HIV seroconversions occurred overall, with four documented during the self-administered phase (two with the time-driven regimen and two with the event-driven regimen). Adherence to the assigned regimen was 75% (7283 of 9652 doses taken) for women allocated the daily regimen compared with 65% for those assigned the time-driven regimen (2367 of 3616 doses taken; p=0·0028) and 53% for those allotted the event-driven regimen (1161 of 2203 doses taken; p<0·0001). When sex was reported in the previous week, PrEP drugs were detected (above the lower limits of quantification) more frequently in women assigned the daily regimen (73 [68%] of 107 samples) than in those allocated the time-driven regimen (42 [58%] of 72 samples) and the event-driven regimen (41 [41%] of 99 samples). INTERPRETATION: Daily PrEP dosing resulted in higher coverage of sex events, increased adherence to the regimen, and augmented drug concentrations than did either time-driven or event-driven dosing. These findings support recommendations for daily use of PrEP with oral emtricitabine plus tenofovir disoproxil fumarate in women. FUNDING: HIV Prevention Trials Network.


Asunto(s)
Fármacos Anti-VIH/administración & dosificación , Emtricitabina/administración & dosificación , Infecciones por VIH/prevención & control , Profilaxis Pre-Exposición/métodos , Tenofovir/administración & dosificación , Administración Oral , Adulto , Fármacos Anti-VIH/efectos adversos , Esquema de Medicación , Emtricitabina/efectos adversos , Estudios de Factibilidad , Femenino , Humanos , Cumplimiento de la Medicación , Sudáfrica , Tenofovir/efectos adversos , Resultado del Tratamiento , Adulto Joven
8.
J Empir Res Hum Res Ethics ; 11(4): 322-333, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27830644

RESUMEN

There has not been enough study of the processes by which site staff help participating community members and potential participants to understand complicated concepts for HIV vaccine trials. This article describes strategies reported in six focus group discussions with Community Advisory Board members, educators, and consent counselors at an active HIV vaccine trial site in South Africa. Thematic analysis identified a considerable range of strategies, and findings suggest that such staff do not only try to promote understanding of critical information but also try to build trust in communicated information, to respect cultural differences, and to promote voluntariness. Findings also suggest occasional tensions between these implicit goals. Actual engagement and consent encounters at HIV vaccine trial sites should be observed, recorded, and analyzed; and the relationship between practices and valued outcomes should be assessed. These efforts may help to make consent-related encounters as "potent" as possible given finite resources.


Asunto(s)
Vacunas contra el SIDA , Investigación Biomédica/ética , Investigación Participativa Basada en la Comunidad , Relaciones Comunidad-Institución , Infecciones por VIH , Consentimiento Informado , Características de la Residencia , Comités Consultivos , Comunicación , Comprensión , Cultura , Ética en Investigación , Grupos Focales , Humanos , Investigadores , Sujetos de Investigación , Sudáfrica , Confianza , Voluntarios
9.
PLoS One ; 10(9): e0137666, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26368824

RESUMEN

BACKGROUND: The Phase 2b double-blinded, randomized Phambili/HVTN 503 trial evaluated safety and efficacy of the MRK Ad5 gag/pol/nef subtype B HIV-1 preventive vaccine vs placebo in sexually active HIV-1 seronegative participants in South Africa. Enrollment and vaccinations stopped and participants were unblinded but continued follow-up when the Step study evaluating the same vaccine in the Americas, Caribbean, and Australia was unblinded for non-efficacy. Final Phambili analyses found more HIV-1 infections amongst vaccine than placebo recipients, impelling the HVTN 503-S recall study. METHODS: HVTN 503-S sought to enroll all 695 HIV-1 uninfected Phambili participants, provide HIV testing, risk reduction counseling, physical examination, risk behavior assessment and treatment assignment recall. After adding HVTN 503-S data, HIV-1 infection hazard ratios (HR vaccine vs. placebo) were estimated by Cox models. RESULTS: Of the 695 eligible, 465 (67%) enrolled with 230 from the vaccine group and 235 from the placebo group. 38% of the 184 Phambili dropouts were enrolled. Enrollment did not differ by treatment group, gender, or baseline HSV-2. With the additional 1286 person years of 503-S follow-up, the estimated HR over Phambili and HVTN 503-S follow-up was 1.52 (95% CI 1.08-2.15, p = 0.02, 82 vaccine/54 placebo infections). The HR was significant for men (HR = 2.75, 95% CI 1.49, 5.06, p = 0.001) but not for women (HR = 1.12, 95% CI 0.73, 1.72, p = 0.62). CONCLUSION: The additional follow-up from HVTN 503-S supported the Phambili finding of increased HIV-1 acquisition among vaccinated men and strengthened the evidence of lack of vaccine effect among women. TRIAL REGISTRATION: clinicaltrials.gov NCT00413725 SA National Health Research Database DOH-27-0207-1539.


Asunto(s)
Vacunas contra el SIDA/administración & dosificación , Infecciones por VIH/epidemiología , Vacunas contra el SIDA/efectos adversos , Vacunas contra el SIDA/inmunología , Método Doble Ciego , Femenino , Estudios de Seguimiento , Infecciones por VIH/inmunología , Infecciones por VIH/prevención & control , Humanos , Masculino , Modelos de Riesgos Proporcionales , Factores de Riesgo , Sudáfrica , Resultado del Tratamiento
10.
PLoS One ; 9(11): e112303, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25401780

RESUMEN

UNLABELLED: 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.


Asunto(s)
Vacunas contra el SIDA/inmunología , Genitales/inmunología , Infecciones por VIH/prevención & control , VIH-1/inmunología , Membrana Mucosa/inmunología , Manejo de Especímenes , Vacunas contra el SIDA/administración & dosificación , Adolescente , Adulto , Femenino , Genitales/virología , Infecciones por VIH/inmunología , Humanos , Masculino , Persona de Mediana Edad , Membrana Mucosa/virología , Factores de Riesgo , Sudáfrica/epidemiología , Adulto Joven
11.
Vaccine ; 32(20): 2328-36, 2014 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-24598726

RESUMEN

Understanding the impact of HIV diversity on immunological responses to candidate immunogens is critical for HIV vaccine development. We investigated the reactivity and immunodominance patterns of HIV-1 consensus group M Gag and Nef in (i) Cameroon, where individuals infected with the predominant CRF02_AG clade were compared with those infected with diverse non-CRF02_AG clades; and (ii) in a multiclade epidemic, namely Cameroon, compared with a monoclade C epidemic, South Africa. We analyzed 57 HIV-infected individuals from Cameroon and 44 HIV-infected individuals from South Africa for differences in detecting HIV-1 consensus M Gag and Nef T cell responses using the IFN-γ ELISpot assay. We found no difference in the predicted epitope coverage between CRF02_AG and non-CRF02_AG viruses for either Gag or Nef. There were no differences in the magnitude and breadth of responses for CRF02_AG and non-CRF02_AG-infected individuals. In contrast, the specificity of epitope targeting was markedly different between the two groups, with fewer than one third (11/38) of peptides commonly recognized in Gag. Furthermore, only one peptide was commonly recognized by at least three individuals from both AG and non-AG groups, indicating poor immunodominance. For Nef, more than half of all targeted peptides (14/27) were recognized by both groups, and four peptides were commonly targeted by at least three individuals. Three times more peptides were exclusively targeted in the diverse non-CRF02_AG group compared to the CRF02_AG group (10 vs. 3). Of note, similar results were obtained when South Africa, a monoclade C epidemic, and Cameroon, a multiclade epidemic, were compared. The central nature of HIV-1 consensus M sequences resulted in their broad recognition, but failed to identify highly immunodominant peptides between homogeneous and diverse HIV epidemics.


Asunto(s)
Infecciones por VIH/inmunología , VIH-1/clasificación , Epítopos Inmunodominantes/inmunología , Linfocitos T/inmunología , Vacunas contra el SIDA/inmunología , Adulto , Secuencia de Aminoácidos , Camerún , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sudáfrica , Adulto Joven , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/inmunología , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/inmunología
12.
Lancet Infect Dis ; 14(5): 388-96, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24560541

RESUMEN

BACKGROUND: The HVTN 503/Phambili study, which assessed the efficacy of the Merck Ad5 gag/pol/nef subtype B HIV-1 preventive vaccine in South Africa, was stopped when futility criteria in the Step study (assessing the same vaccine in the Americas, Caribbean, and Australia) were met. Here we report long-term follow-up data. METHODS: HVTN 503/Phambili was a double-blind, placebo-controlled, randomised trial that recruited HIV-1 uninfected, sexually active adults aged 18-35 years from five sites in South Africa. Eligible participants were randomly assigned (1:1) by computer-generated random numbers to either vaccine or placebo, stratified by site and sex. Cox proportional hazards models were used to estimate HIV-1 infection in the modified intention-to-treat cohort, all of whom were unmasked early in follow-up. The trial is registered with ClinicalTrials.gov, number NCT00413725 and the South African National Health Research Database, number DOH-27-0207-1539. FINDINGS: Between Jan 24, 2007, and Sept 19, 2007, 801 participants (26·7%) of a planned 3000 were randomly assigned (400 to vaccine, 401 to placebo); 216 (27%) received only one injection, 529 (66%) received only two injections, and 56 (7%) received three injections. At a median follow-up of 42 months (IQR 31-42), 63 vaccine recipients (16%) had HIV-1 infection compared with 37 placebo recipients (9%; adjusted HR 1·70, 95% CI 1·13-2·55; p=0·01). Risk for HIV-1 infection did not differ according to the number of vaccinations received, sex, circumcision, or adenovirus type 5 (Ad5) serostatus. Differences in risk behaviour at baseline or during the study, or annualised dropout rate (7·7% [95% CI 6·2-9·5] for vaccine recipients vs 8·8% [7·1-10·7] for placebo recipients; p=0·40) are unlikely explanations for the increased rate of HIV-1 infections seen in vaccine recipients. INTERPRETATION: The increased risk of HIV-1 acquisition in vaccine recipients, irrespective of number of doses received, warrants further investigation to understand the biological mechanism. We caution against further use of the Ad5 vector for HIV vaccines. FUNDING: National Institute of Allergy and Infectious Diseases, Merck, and South African Medical Research Council.


Asunto(s)
Vacunas contra el SIDA/administración & dosificación , Adenoviridae/genética , Vectores Genéticos , Infecciones por VIH/prevención & control , Precursores de Proteínas/inmunología , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/inmunología , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/inmunología , Productos del Gen pol del Virus de la Inmunodeficiencia Humana/inmunología , Adolescente , Adulto , Método Doble Ciego , Femenino , Estudios de Seguimiento , Infecciones por VIH/epidemiología , Humanos , Incidencia , Masculino , Modelos de Riesgos Proporcionales , Medición de Riesgo , Sudáfrica , Vacunas Sintéticas/inmunología , Adulto Joven
13.
S Afr Med J ; 102(6): 571-3, 2012 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-22668967

RESUMEN

BACKGROUND: Traditional circumcision is practised among some indigenous tribes in South Africa (SA) such as the Xhosa. Recent experimental evidence has demonstrated the benefits of male circumcision for the prevention of HIV infection in heterosexual men. The acceptability of circumcision as a biomedical intervention mirroring an ingrained cultural practice, as well as the age and extent of the procedure, are poorly understood. METHODS: Men aged 15 - 42 years were recruited in a peri-urban settlement near Cape Town. Participants completed an interviewer-administered questionnaire assessing self-reported circumcision status, context and reasons for previous or planned circumcision, and willingness to undergo medical circumcision for themselves or their sons. Results were confirmed by clinical examination. The most recent HIV test result was compared with circumcision status. RESULTS: Of the 199 men enrolled, 148 (74%) reported being traditionally circumcised; of the 51 not circumcised, 50 were planning the traditional procedure. Among men self-reporting circumcision, 40 (27%) had some or all of the foreskin remaining. The median age at traditional circumcision was 21 years (interquartile range 19 - 22 years). While knowledge of the preventive benefit of circumcision was reported by 128 men (66%), most were unwilling to undergo medical circumcision or allow their sons to do so, because of religion/culture, notions of manhood, and social disapproval. CONCLUSION: Almost all men in this study had undergone or were planning to undergo traditional circumcision and were largely opposed to the medically performed procedure. In the majority, traditional circumcision had occurred after the mean age of sexual debut and almost a quarter were found to have only partial foreskin removal. To ensure optimal HIV prevention benefits, strategies to facilitate complete foreskin removal prior to sexual debut within traditional circumcision practices require further attention.


Asunto(s)
Población Negra , Circuncisión Masculina/etnología , Cultura , Infecciones por VIH/prevención & control , Aceptación de la Atención de Salud/etnología , Adolescente , Adulto , Humanos , Masculino , Examen Físico , Sudáfrica , Encuestas y Cuestionarios , Adulto Joven
14.
J Acquir Immune Defic Syndr ; 59(2): 185-93, 2012 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-22227488

RESUMEN

OBJECTIVE: To identify and describe populations at risk for HIV in 3 clinical research centers in Kenya and South Africa. DESIGN: Prospective cohort study. METHODS: Volunteers reporting recent sexual activity, multiple partners, transactional sex, sex with an HIV-positive partner, or, if male, sex with men (MSM; in Kenya only) were enrolled. Sexually active minors were enrolled in South Africa only. Risk behavior, HIV testing, and clinical data were obtained at follow-up visits. RESULTS: From 2005 to 2008, 3023 volunteers were screened, 2113 enrolled, and 1834 contributed data on HIV incidence. MSM had the highest HIV incidence rate of 6.8 cases per 100 person-years [95% confidence interval (CI): 4.9 to 9.2] followed by women in Kilifi and Cape Town (2.7 cases per 100 person-years, 95% CI: 1.7 to 4.2). No seroconversions were observed in Nairobi women or men in Nairobi or Cape Town who were not MSM. In 327 MSM, predictors of HIV acquisition included report of genital ulcer (Hazard Ratio: 4.5, 95% CI: 1.7 to 11.6), not completing secondary school education (HR: 3.4, 95% CI: 1.6 to 7.2) and reporting receptive anal intercourse (HR: 8.2, 95% CI: 2.7 to 25.0). Paying for sex was inversely associated with HIV infection (HR: 0.2, 95% CI: 0.04 to 0.8). 279 (13.0%) volunteers did not return after the first visit; subsequent attrition rates ranged from 10.4 to 21.8 volunteers per 100 person-years across clinical research centers. CONCLUSIONS: Finding, enrolling, and retaining risk populations for HIV prevention trials is challenging in Africa. African MSM are not frequently engaged for research, have high HIV incidence, need urgent risk reduction counseling, and may represent a suitable population for future HIV prevention trials.


Asunto(s)
Infecciones por VIH/epidemiología , Homosexualidad Masculina , Asunción de Riesgos , Trabajo Sexual , Adolescente , Adulto , Anciano , Femenino , Humanos , Incidencia , Kenia/epidemiología , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Factores de Riesgo , Conducta Sexual , Sudáfrica/epidemiología , Adulto Joven
15.
PLoS One ; 7(4): e31387, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22532824

RESUMEN

BACKGROUND: HIV prevention trials are increasingly being conducted in sub-Saharan Africa. Women at risk for HIV are also at risk of pregnancy. To maximize safety, women agree to avoid pregnancy during trials, yet pregnancies occur. Using data from the HVTN 503/"Phambili" vaccine trial, we report pregnancy incidence during and after the vaccination period and identify factors, measured at screening, associated with incident pregnancy. METHODS: To enrol in the trial, women agreed and were supported to avoid pregnancy until 1 month after their third and final vaccination ("vaccination period"), corresponding to the first 7 months of follow-up. Unsterilized women, pooled across study arms, were analyzed. Poisson regression compared pregnancy rates during and after the vaccination period. Cox proportional hazards regression identified associations with first pregnancy. RESULTS: Among 352 women (median age 23 yrs; median follow-up 1.5 yrs), pregnancy incidence was 9.6/100 women-years overall and 6.8/100 w-yrs and 11.3/100 w-yrs during and after the vaccination period, respectively [Rate Ratio = 0.60 (0.32-1.14), p = 0.10]. In multivariable analysis, pregnancy was reduced among women who: enrolled at sites providing contraception on-site [HR = 0.43, 95% CI (0.22-0.86)]; entered the trial as injectable contraceptive users [HR = 0.37 (0.21-0.67)] or as consistent condom users (trend) [HR = 0.54 (0.28-1.04)]. Compared with women with a single partner of HIV-unknown status, pregnancy rates were increased among women with: a single partner whose status was HIV-negative [HR = 2.34(1.16-4.73)] and; 2 partners both of HIV-unknown status [HR = 4.42(1.59-12.29)]. Women with 2 more of these risk factors: marijuana use, heavy drinking, or use of either during sex, had increased pregnancy incidence [HR = 2.66 (1.24-5.72)]. CONCLUSIONS: It is possible to screen South African women for pregnancy risk at trial entry. Providing injectable contraception for free on-site and supporting consistent condom use may reduce incident pregnancy. Screening should determine the substance use, partnering, and HIV status of both members of the couple for both pregnancy and HIV prevention. TRIAL REGISTRATION: SA National Health Research Database DOH-27-0207-1539; Clinicaltrials.gov NCT00413725.


Asunto(s)
Vacunas contra el SIDA , Conducta Anticonceptiva/estadística & datos numéricos , Infecciones por VIH/prevención & control , Índice de Embarazo , Adulto , Femenino , Humanos , Embarazo , Sudáfrica
16.
Lancet Infect Dis ; 11(7): 507-15, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21570355

RESUMEN

BACKGROUND: The MRKAd5 HIV-1 gag/pol/nef subtype B vaccine was designed to elicit T-cell-mediated immune responses capable of providing complete or partial protection from HIV-1 infection or a decrease in viral load after acquisition. We aim to assess the safety and efficacy of the vaccine in South Africa, where the major circulating clade is subtype C. METHODS: We did a phase 2b double-blind, randomised test-of-concept study in sexually active HIV-1 seronegative participants at five sites in South Africa. Randomisation was by a computer-generated random number sequence. The vaccine and placebo were given by intramuscular injection on a 0, 1, 6 month schedule. Our coprimary endpoints were a vaccine-induced reduction in HIV-1 acquisition and viral-load setpoint. These endpoints were assessed independently in the modified intention-to-treat (MITT) cohort with two-tailed significance tests stratified by sex. We assessed immunogenicity by interferon-γ ELISPOT in peripheral-blood mononuclear cells. After the lack of efficacy of the MRKAd5 HIV-1 vaccine in the Step study, enrolment and vaccination in our study was halted, treatment allocations were unmasked, and follow-up continued. This study is registered with the South Africa National Health Research Database, number DOH-27-0207-1539, and ClinicalTrials.gov, number NCT00413725. FINDINGS: 801 of a scheduled 3000 participants, of whom 360 (45%) were women, were randomly assigned to receive either vaccine or placebo. 445 participants (56%) had adenovirus serotype 5 (Ad5) titres greater than 200, and 129 men (29%) were circumcised. 34 MITT participants in the vaccine group were diagnosed with HIV-1 (incidence rate 4·54 per 100 person-years) and 28 in the placebo group (3·70 per 100 person-years). There was no evidence of vaccine efficacy; the hazard ratio adjusted for sex was 1·25 (95% CI 0·76-2·05). Vaccine efficacy did not differ by Ad5 titre, sex, age, herpes simplex virus type 2 status, or circumcision. The geometric mean viral-load setpoint was 20,483 copies per mL (n=33) in the vaccine group and 34,032 copies per mL (n=28) in the placebo group (p=0·39). The vaccine elicited interferon-γ-secreting T cells that recognised both clade B (89%) and C (77%) antigens. INTERPRETATION: The MRKAd5 HIV-1 vaccine did not prevent HIV-1 infection or lower viral-load setpoint; however, stopping our trial early probably compromised our ability to draw conclusions. The high incidence rates noted in South Africa highlight the crucial need for intensified efforts to develop an efficacious vaccine. FUNDING: The US National Institute of Allergy and Infectious Disease and Merck and Co Inc.


Asunto(s)
Vacunas contra el SIDA/administración & dosificación , Infecciones por VIH/prevención & control , VIH-1/inmunología , Vacunas contra el SIDA/efectos adversos , Vacunas contra el SIDA/inmunología , Adolescente , Adulto , Estudios de Cohortes , Método Doble Ciego , Femenino , Infecciones por VIH/inmunología , Humanos , Inmunidad Celular/inmunología , Interferón gamma/sangre , Masculino , Modelos de Riesgos Proporcionales , ARN Viral/sangre , Sudáfrica , Adulto Joven
17.
Vaccine ; 29(32): 5203-9, 2011 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-21619905

RESUMEN

Recombinant adenovirus serotype 5 (rAd5) vaccine vectors for HIV-1 and other pathogens have been shown to be limited by high titers of Ad5 neutralizing antibodies (NAbs) in the developing world. Alternative serotype rAd vectors have therefore been constructed. Here we report Ad5, Ad26, Ad35, and Ad48 NAb titers in 4381 individuals from North America, South America, sub-Saharan Africa, and Southeast Asia. As expected, Ad5 NAb titers were both frequent and high magnitude in sub-Saharan Africa and Southeast Asia. In contrast, Ad35 NAb titers proved infrequent and low in all regions studied, and Ad48 NAbs were rare in all regions except East Africa. Ad26 NAbs were moderately common in adults in sub-Saharan Africa and Southeast Asia, but Ad26 NAb titers proved markedly lower than Ad5 NAb titers in all regions, and these relatively low Ad26 NAb titers did not detectably suppress the immunogenicity of 4×10(10)vp of a rAd26-Gag/Pol/Env/Nef vaccine in rhesus monkeys. These data inform the clinical development of alternative serotype rAd vaccine vectors in the developing world.


Asunto(s)
Infecciones por Adenoviridae/epidemiología , Infecciones por Adenoviridae/inmunología , Adenoviridae/inmunología , Anticuerpos Antivirales/inmunología , Vacunas Virales/inmunología , Vacunas contra el SIDA/inmunología , Adenoviridae/aislamiento & purificación , Infecciones por Adenoviridae/sangre , Infecciones por Adenoviridae/virología , Adolescente , Adulto , Animales , Anticuerpos Antivirales/sangre , Niño , VIH-1/inmunología , Humanos , Lactante , Macaca mulatta/inmunología , Vacunas Sintéticas/inmunología , Adulto Joven
18.
Sex Transm Infect ; 83(5): 383-6, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17567686

RESUMEN

OBJECTIVE: To investigate attitudes to directly observed antiretroviral therapy (DOT ART) among HIV infected adults attending a workplace HIV care programme in South Africa. METHODS: Clients attending workplace HIV clinics in two regions were interviewed using a semi-structured questionnaire. RESULTS: 100 individuals (99% male, mean age 40.2 years) participated, 61% were already taking ART by self administration. 71% had previous tuberculosis (TB) with the majority having received DOT for TB. 65% of individuals indicated that they would not like to receive ART by DOT-the main reason given was a desire to take responsibility for their own treatment. This contrasted with 79% who thought TB treatment by DOT a good idea. On questioning about disclosure, 70% reported disclosure to their sexual partners and 21% to fellow workers. 78% of individuals indicated willingness to support someone else taking ART. CONCLUSION: ART by DOT was not an immediately popular concept with our patients, primarily because of a desire to retain responsibility for their own treatment. More work is needed to understand what key elements of treatment support are needed to promote adherence.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Actitud Frente a la Salud , Terapia por Observación Directa/psicología , Infecciones por VIH/tratamiento farmacológico , Lugar de Trabajo , Adulto , Estudios Transversales , Femenino , Humanos , Masculino , Sudáfrica
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