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Governance and leadership are recognised as central to health system development in low- and middle-income countries, yet few existing studies consider the influence of multi-level governance systems. South Africa is one of many (quasi-)federal states. Provincial governments have responsibility for managing health care delivery within national policy frameworks and norms. The early post-apartheid period saw country-wide efforts to address the apartheid legacy of health system inequity and inefficiency, but health system transformation subsequently stalled in many provinces. In contrast, the Western Cape provincial health department sustained service delivery reform and strengthened management processes over the period 1994-2016. This department can be considered a 'pocket of relative bureaucratic effectiveness' (POE): an organisational entity that, compared to others, is relatively effective in carrying out its functions in pursuit of the public good. This paper considers what factors enabled the development of the Western Cape health system in the period 1994-2016. Two phases of data collection entailed document review, participatory workshops, 43 in-depth interviews with purposively selected key informants from inside and outside the Western Cape, and a structured survey testing initial insights (response rate 42%). Analysis included triangulation across data sets, comparison between the Western Cape and other provincial experience and deeper reflection on these experiences drawing on POE theory and public administration literature. The analysis highlights the Western Cape experience of stable and astute sub-national governance and leadership and the deepening of administrative and technical capacity over time - within a specific provincial historical and political economy context that sustained the separation of political and administrative powers. Multi-level governance systems can create the space for sub-national POEs to emerge in their mediation of wider political economy forces, generating spaces for skilled reform leaders to act in the public interest, support the emergence of distributed leadership and develop robust management processes.
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There are few data on the real-world effectiveness of COVID-19 vaccines and boosting in Africa, which experienced widespread SARS-CoV-2 infection before vaccine availability. We assessed the association between vaccination and severe COVID-19 in the Western Cape, South Africa, in an observational cohort study of >2 million adults during 2020-2022. We described SARS-CoV-2 testing, COVID-19 outcomes, and vaccine uptake over time. We used multivariable cox models to estimate the association of BNT162b2 and Ad26.COV2.S vaccination with COVID-19-related hospitalization and death, adjusting for demographic characteristics, underlying health conditions, socioeconomic status proxies, and healthcare utilization. We found that by the end of 2022, 41% of surviving adults had completed vaccination and 8% had received a booster dose. Recent vaccination was associated with notable reductions in severe COVID-19 during periods dominated by Delta, and Omicron BA.1/2 and BA.4/5 (sub)lineages. During the latest Omicron BA.4/5 wave, within 3 months of vaccination or boosting, BNT162b2 and Ad26.COV2.S were each 84% effective against death (95% CIs: 57-94 and 49-95, respectively). However, distinct reductions of effectiveness occurred at longer times post completing or boosting vaccination. Results highlight the importance of continued emphasis on COVID-19 vaccination and boosting for those at high risk of severe COVID-19, even in settings with widespread infection-induced immunity.
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Background: There are few data on the real-world effectiveness of COVID-19 vaccines and boosting in Africa, which experienced high levels of SARS-CoV-2 infection in a mostly vaccine-naïve population, and has limited vaccine coverage and competing health service priorities. We assessed the association between vaccination and severe COVID-19 in the Western Cape, South Africa. Methods: We performed an observational cohort study of >2 million adults during 2020-2022. We described SARS-CoV-2 testing, COVID-19 outcomes, and vaccine uptake over time. We used multivariable cox models to estimate the association of BNT162b2 and Ad26.COV2.S vaccination with COVID-19-related hospitalisation and death, adjusting for demographic characteristics, underlying health conditions, socioeconomic status proxies and healthcare utilisation. Results: By end 2022, only 41% of surviving adults had completed vaccination and 8% a booster dose, despite several waves of severe COVID-19. Recent vaccination was associated with notable reductions in severe COVID-19 during distinct analysis periods dominated by Delta, Omicron BA.1/2 and BA.4/5 (sub)lineages: within 6 months of completing vaccination or boosting, vaccine effectiveness was 46-92% for death (range across periods), 45-92% for admission with severe disease or death, and 25-90% for any admission or death. During the Omicron BA.4/5 wave, within 3 months of vaccination or boosting, BNT162b2 and Ad26.COV2.S were each 84% effective against death (95% CIs: 57-94 and 49-95, respectively). However, there were distinct reductions of VE at larger times post completing or boosting vaccination. Conclusions: Continued emphasis on regular COVID-19 vaccination including boosting is important for those at high risk of severe COVID-19 even in settings with widespread infection-induced immunity.
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OBJECTIVE: Researching how public-private engagements may promote universal access to safe obstetric care including caesarean delivery is essential. The aim of this research was to document the utilisation of private general practitioners (GPs) contracted to provide caesarean delivery services in five rural district hospitals in the Western Cape, the profile and outcomes of caesarean deliveries. We also describe stakeholder experiences of these arrangements in order to inform potential models of public-private contracting for obstetric services. DESIGN: We used a mixed-methods study design to describe rural district hospitals' utilisation of private GP contracting for caesarean deliveries. Between April 2021 and March 2022, we collated routine data from delivery and theatre registers to capture the profile of deliveries and maternal outcomes. We conducted 23 semistructured qualitative interviews with district managers, hospital-employed doctors and private GPs to explore their experiences of the contracting arrangements. SETTING: The study was conducted in five rural district hospitals in the Western Cape province, South Africa. RESULTS: The use of private GPs as surgeon or anaesthetist for caesarean deliveries differed widely across the hospitals. Overall, the utilisation of private GPs for anaesthetics was similar (29% of all caesarean deliveries) to the utilisation of private GPs as surgeons (33% of all caesarean deliveries). The proportion of caesarean deliveries undertaken by private GPs as the primary surgeon was inversely related to size of hospital and mean monthly deliveries. Adverse outcomes following a caesarean delivery were rare. Qualitative data provided insights into contributions made by private GPs and the contracting models, which did not incentivise overservicing. CONCLUSION: The findings of this study suggest that private GPs can play an important role in filling gaps and expanding quality care in rural public facilities that have insufficient obstetric skills and expertise. Different approaches to enable access to safe caesarean delivery are needed for different contexts, and contracting with experienced private GP's is one resource for rural district hospitals to consider.
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Clínicos Gerais , Feminino , Gravidez , Humanos , África do Sul , Hospitais Públicos , Hospitais de Distrito , CesáreaRESUMO
Delegates at the first International African Vaccinology Conference noted, with dismay, that many African children have limited access to existing and new vaccines as a consequence of weak immunisation programmes, lack of political will, and high vaccine prices. This inequality is a denial of the African child her basic right to a healthy life, and jeopardises long term economic growth on the continent. In addition, there is insufficient emphasis in Africa on adolescent and adult immunisation. The delegates documented various concerns and made various commitments; contained in this Cape Town Declaration on Vaccines, adopted on 11 November 2012. Finally, delegates confirmed their agreement with the goals and strategic objectives of the Global Vaccine Action Plan, and committed to hold African leaders accountable for its implementation during the Decade of Vaccines. The full list of registered conference delegates is provided as supplementary data to this manuscript.
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Disparidades em Assistência à Saúde , Programas de Imunização/organização & administração , Vacinas/uso terapêutico , África , Congressos como Assunto , Humanos , VacinaçãoRESUMO
BACKGROUND: An incomplete understanding of the immunological mechanisms underlying protection against tuberculosis (TB) hampers the development of new vaccines against TB. We aimed to define host correlates of prospective risk of TB disease following bacille Calmette-Guérin (BCG) vaccination. METHODS: In this study, 5,726 infants vaccinated with BCG at birth were enrolled. Host responses in blood collected at 10 weeks of age were compared between infants who developed pulmonary TB disease during 2 years of follow-up (cases) and those who remained healthy (controls). RESULTS: Comprehensive gene expression and cellular and soluble marker analysis failed to identify a correlate of risk. We showed that distinct host responses after BCG vaccination may be the reason: two major clusters of gene expression, with different myeloid and lymphoid activation and inflammatory patterns, were evident when all infants were examined together. Cases from each cluster demonstrated distinct patterns of gene expression, which were confirmed by cellular assays. CONCLUSIONS: Distinct patterns of host responses to Mycobacterium bovis BCG suggest that novel TB vaccines may also elicit distinct patterns of host responses. This diversity should be considered in future TB vaccine development.
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Adjuvantes Imunológicos/efeitos adversos , Vacina BCG/efeitos adversos , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Tuberculose/prevenção & controle , Vacinação/efeitos adversos , Adjuvantes Imunológicos/administração & dosagem , Vacina BCG/administração & dosagem , Estudos de Casos e Controles , Feminino , Regulação Bacteriana da Expressão Gênica/imunologia , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Prospectivos , Tuberculose/imunologiaRESUMO
One means of improving healthcare workers' knowledge of and attitudes to vaccines is through running vaccine conferences which are accessible, affordable, and relevant to their everyday work. Various vaccinology conferences are held each year worldwide. These meetings focus heavily on basic science with much discussion about new developments in vaccines, and relatively little coverage of policy, advocacy, and communication issues. A negligible proportion of delegates at these conferences come from Africa, home to almost 40% of the global burden of vaccine-preventable diseases. To the best of our knowledge, no major vaccinology conference has ever been held on the African continent apart from World Health Organization (WHO) meetings. The content of the first International African Vaccinology Conference was planned to be different; to focus on the science, with a major part of discussions being on clinical, programmatic, policy, and advocacy issues. The conference was held in Cape Town, South Africa, from 8 to 11 November 2012. The theme of the conference was "Advocating for efforts to protect African children, families, and communities from the threat of infectious diseases". There were more than 550 registered participants from 55 countries (including 37 African countries). There were nine pre-conference workshops, ten plenary sessions, and 150 oral and poster presentations. The conference discussed the challenges to universal immunisation in Africa as well as the promotion of dialogue and communication on immunisation among all stakeholders. There was general acknowledgment that giant strides have been made in Africa since the global launch of the Expanded Programme on Immunisation in 1974. For example, there has been significant progress in introducing new and under-utilised vaccines; including hepatitis B, Haemophilus influenza type b, pneumococcal conjugate, rotavirus, meningococcal A conjugate, and human papillomavirus vaccines. In May 2012, African countries endorsed the Global Vaccine Action Plan at the World Health Assembly. However, more than six million children remain incompletely vaccinated in Africa leading to more than one million vaccine-preventable deaths annually. In addition, there are persistent problems with leadership and planning, vaccine stock management, supply chain capacity and quality, provider-parent communication, and financial sustainability. The conference delegates agreed to move from talking to taking concrete actions around children's health, and to ensure that African governments commit to saving children's lives. They would advocate for lower costs of immunisation programmes in Africa, perhaps through bulk buying and improved administration of vaccine rollout through the New Partnership for Africa's Development.
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Programas de Imunização/organização & administração , Vacinação/métodos , Vacinas/administração & dosagem , África , Criança , Controle de Doenças Transmissíveis/métodos , Conhecimentos, Atitudes e Prática em Saúde , Pessoal de Saúde , HumanosRESUMO
Healthcare workers (HCWs) are at high risk of Mycobacterium tuberculosis (Mtb) infection and tuberculosis disease, but also play a crucial role in implementing healthcare. Preexposure tuberculosis vaccination, including revaccination with BCG, might benefit Mtb-uninfected HCWs, but most HCWs in tuberculosis-endemic countries are already sensitized to mycobacteria. A new postexposure tuberculosis vaccine offers greatest potential for protection, in the setting of repeated occupational Mtb exposure. Novel strategies for induction of mycobacteria-specific resident memory T cells in the lung by aerosol administration, or induction of T cells with inherent propensity for residing in mucosal sites, such as CD1-restricted T cells and mucosa-associated innate T cells, should be explored. The need for improved protection of HCWs against tuberculosis disease is clear. However, health systems in tuberculosis-endemic countries would need significantly improved occupational health structures to implement a screening and vaccination strategy for HCWs.
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Vacina BCG , Pessoal de Saúde , Doenças Profissionais , Vacinas contra a Tuberculose , Tuberculose , Humanos , Doenças Profissionais/imunologia , Doenças Profissionais/prevenção & controle , Exposição Ocupacional , África do Sul , Tuberculose/imunologia , Tuberculose/prevenção & controleRESUMO
In a Phase 1 trial, we evaluated the safety of AERAS-402, an adenovirus 35-vectored TB vaccine candidate expressing 3 Mycobacterium tuberculosis (Mtb) immunodominant antigens, in subjects with and without latent Mtb infection. HIV-negative, BCG-vaccinated Kenyan adults without evidence of tuberculosis, 10 QuantiFERON(®)-TB Gold In-Tube test (QFT-G)(-) and 10 QFT-G(+), were randomized 4:1 to receive AERAS-402 or placebo as two doses, on Days 0 and 56, with follow up to Day 182. There were no deaths, serious adverse events or withdrawals. For 1 AERAS-402 QFT-G(-) and 1 AERAS-402 QFT-G(+) subject, there were 3 self-limiting severe AEs of injection site pain: 1 after the first vaccination and 1 after each vaccination, respectively. Two additional severe AEs considered vaccine-related were reported after the first vaccination in AERAS-402 QFT-G(+) subjects: elevated blood creatine phosphokinase and neutropenia, the latter slowly improving but remaining abnormal until study end. AERAS-402 was not detected in urine or throat cultures for any subject. In intracellular cytokine staining studies, curtailed by technical issues, we saw modest CD4+ and CD8+ T cell responses to Mtb Ag85A/b peptide pools among both QFT-G(-) and (+) subjects, with trends in the CD4+ T cells suggestive of boosting after the second vaccine dose, slightly more so in QFT-G(+) subjects. CD4+ and CD8+ responses to Mtb antigen TB10.4 were minimal. Increases in Adenovirus 35 neutralizing antibodies from screening to end of study, seen in 50% of AERAS-402 recipients, were mostly minimal. This small study confirms acceptable safety and tolerability profiles for AERAS-402, in line with other Phase 1 studies of AERAS-402, now to include QFT-G(+) subjects.
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Anticorpos Antibacterianos/sangue , Vacina BCG , Imunogenicidade da Vacina , Tuberculose Latente/imunologia , Mycobacterium tuberculosis/imunologia , Vacinas contra a Tuberculose/efeitos adversos , Vacinas contra a Tuberculose/imunologia , Aciltransferases/imunologia , Adulto , Anticorpos Neutralizantes/sangue , Antígenos de Bactérias/imunologia , Vacina BCG/imunologia , Proteínas de Bactérias/imunologia , Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Creatina Quinase/sangue , Citocinas/imunologia , Feminino , Voluntários Saudáveis , Humanos , Interferon gama/imunologia , Quênia/epidemiologia , Masculino , Pessoa de Meia-Idade , Neutropenia/etiologia , Tuberculose/epidemiologia , Tuberculose/prevenção & controle , Vacinação , Vacinas de DNA , Adulto JovemRESUMO
RATIONALE: Tuberculosis (TB) is a major cause of morbidity and mortality worldwide, thus there is an urgent need for novel TB vaccines. OBJECTIVES: We investigated a novel TB vaccine candidate, M72/AS01, in a phase IIa trial of bacille Calmette-Guérin-vaccinated, HIV-uninfected, and Mycobacterium tuberculosis (Mtb)-infected and -uninfected adults in South Africa. METHODS: Two doses of M72/AS01 were administered to healthy adults, with and without latent Mtb infection. Participants were monitored for 7 months after the first dose; cytokine production profiles, cell cycling, and regulatory phenotypes of vaccine-induced T cells were measured by flow cytometry. MEASUREMENTS AND MAIN RESULTS: The vaccine had a clinically acceptable safety profile, and induced robust, long-lived M72-specific T-cell and antibody responses. M72-specific CD4 T cells produced multiple combinations of Th1 cytokines. Analysis of T-cell Ki67 expression showed that most vaccination-induced T cells did not express Th1 cytokines or IL-17; these cytokine-negative Ki67(+) T cells included subsets of CD4 T cells with regulatory phenotypes. PD-1, a negative regulator of activated T cells, was transiently expressed on M72-specific CD4 T cells after vaccination. Specific T-cell subsets were present at significantly higher frequencies after vaccination of Mtb-infected versus -uninfected participants. CONCLUSIONS: M72/AS01 is clinically well tolerated in Mtb-infected and -uninfected adults, induces high frequencies of multifunctional T cells, and boosts distinct T-cell responses primed by natural Mtb infection. Moreover, these results provide important novel insights into how this immunity may be appropriately regulated after novel TB vaccination of Mtb-infected and -uninfected individuals.Clinical trial registered with www.clinicaltrials.gov (NCT 00600782).
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Linfócitos T/imunologia , Vacinas contra a Tuberculose/imunologia , Adulto , Antígenos CD4/metabolismo , Antígenos CD8/metabolismo , Feminino , Citometria de Fluxo , Humanos , Imunidade Celular/imunologia , Imunidade Humoral/imunologia , Interleucina-17/metabolismo , Masculino , África do Sul , Vacinas contra a Tuberculose/administração & dosagem , Adulto JovemRESUMO
BACKGROUND: The Expanded Programme on Immunisation (EPI) is one of the most powerful and cost-effective public health programmes to improve child survival. We assessed challenges and enablers for the programme in South Africa, as we approach the 2015 deadline for the Millennium Development Goals. METHODS: Between September 2009 and September 2010 we requested national and provincial EPI managers in South Africa to identify key challenges facing EPI, and to propose appropriate solutions. We collated their responses and searched for systematic reviews on the effectiveness of the proposed solutions; in the Health Systems Evidence, Cochrane Library, and PubMed electronic databases. We screened the search outputs, selected systematic reviews, extracted data, and assessed the quality of included reviews (using AMSTAR) and the quality of the evidence (using GRADE) in duplicate; resolving disagreements by discussion and consensus. RESULTS: Challenges identified by EPI managers were linked to healthcare workers (insufficient knowledge of vaccines and immunisation), the public (anti-immunisation rumours and reluctance from parents), and health system (insufficient financial and human resources). Strategies proposed by managers to overcome the challenges include training, supervision, and audit and feedback; strengthening advocacy and social mobilisation; and sustainable EPI funding schemes, respectively. The findings from reliable systematic reviews indicate that interactive educational meetings, audit and feedback, and supportive supervision improve healthcare worker performance. Structured and interactive communication tools probably increase parents' understanding of immunisation; and reminders and recall, use of community health workers, conditional cash transfers, and mass media interventions probably increase immunisation coverage. Finally, a national social health insurance scheme is a potential EPI financing mechanism; however, given the absence of high-quality evidence of effects, its implementation should be pilot-tested and the impacts and costs rigorously monitored. CONCLUSION: In line with the Millennium Development Goals, we have to ensure that our children's right to health, development and survival is respected, protected and promoted. EPI is central to this vision. We found numerous promising strategies for improving EPI performance in South Africa. However, their implementation would need to be tailored to local circumstances and accompanied by high-quality monitoring and evaluation. The strength of our approach comes from having a strong framework for interventions before looking for systematic reviews. Without a framework, we would have been driven by what reviews have been done and what is easily researchable; rather than the values and preferences of key immunisation stakeholders.
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Pessoal Administrativo/psicologia , Serviços de Saúde da Criança/organização & administração , Programas de Imunização/organização & administração , Criança , Serviços de Saúde da Criança/tendências , Humanos , Programas de Imunização/tendências , Desenvolvimento de Programas , África do SulRESUMO
The nature of research has continued to change considerably over the last century. Our Faculty's challenge has been to keep abreast of those changes to remain at the cutting edge, while contributing meaningfully to the scientific literature which informs clinical and public health practice in South Africa and beyond. The Faculty must possess an agreed-on research strategy that is dynamic and responsive. Over the years our Faculty has 'grown' such a strategy document. This article, summarising its main thrusts, is offered because we feel that while it applies specifically to UCT, the issues raised surely apply to all similar faculties in our country and on the continent, to varying degrees.
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Pesquisa Biomédica , Universidades , Fortalecimento Institucional , Humanos , África do Sul , Pesquisa Translacional Biomédica , Universidades/organização & administraçãoRESUMO
The vision of the South African Tuberculosis Vaccine Initiative (SATVI) (www.satvi.uct.ac.za) is 'A World Without TB' and our mission is 'Innovative and high-quality TB vaccine research in Africa, to impact the global epidemic'. Over the last 10 years, our focus has been twofold: first, clinical trials of BCG and of new candidate vaccines, and second, complementary research that addresses critical questions in TB vaccine development. SATVI is now widely regarded as the leading TB vaccine clinical research site in the world.
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Vacinas contra a Tuberculose , Tuberculose Pulmonar/prevenção & controle , Universidades , Adolescente , Adulto , Vacina BCG , Ensaios Clínicos como Assunto , Comportamento Cooperativo , Humanos , Lactente , Mycobacterium tuberculosis/imunologia , Faculdades de Medicina , África do Sul , Tuberculose Pulmonar/imunologiaRESUMO
UNLABELLED: Childhood tuberculosis (TB) is common in high TB burden countries, contributing a substantial proportion to the TB caseload. The HIV epidemic has had a large impact on the incidence, diagnosis and management of childhood TB. AIM: To review the contributions from researchers at the University of Cape Town to the field of childhood TB over the past decades. METHODS: Review of published literature on studies of childhood TB done by investigators from the University of Cape Town. RESULTS: Important advances have been made, especially in the areas of epidemiology, diagnosis and prevention of childhood TB. Epidemiological research has led to improved understanding of the large burden of childhood TB in Cape Town. Advances in diagnosis include use of improved specimens, particularly induced sputum and better diagnostic tests. The efficacy of GeneXpert, a rapid polymerase chain reaction (PCR)-based diagnostic test, on induced sputum specimens, has potential to enable a confirmed diagnosis in children of all ages at a range of healthcare facilities, and represents an important advance in management of children presenting with suspected TB. Advances in prevention include the establishment of a vaccine study site and several studies on immunisation, and on the use of primary isoniazid prophylaxis as an effective preventive strategy in symptomatic HIV-infected children. CONCLUSION: Research in childhood TB has led to important advances in diagnosis and management, enabling better care for HIV-infected and uninfected children.
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Mycobacterium tuberculosis/imunologia , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/prevenção & controle , Universidades , Antituberculosos/uso terapêutico , Criança , Endoscopia , Humanos , Isoniazida/uso terapêutico , África do Sul/epidemiologia , Tuberculose Meníngea/terapia , Tuberculose Pulmonar/epidemiologiaRESUMO
Childhood tuberculosis (TB) is a preventable and curable infectious disease that remains overlooked by public health authorities, health policy makers and TB control programmes. Childhood TB contributes significantly to the burden of disease and represents the failure to control transmission in the community. Furthermore, the pool of infected children constitutes a reservoir of infection for the future burden of TB. It is time to prioritise childhood TB, advocate for addressing the challenges and grasp the opportunities in its prevention and control. Herein, we propose a scientifically informed advocacy agenda developed at the International Childhood TB meeting held in Stockholm, Sweden, from March 17 to 18, 2011, which calls for a renewed effort to improve the situation for children affected by Mycobacterium tuberculosis exposure, infection or disease. The challenges and needs in childhood TB are universal and apply to all settings and must be addressed more effectively by all stakeholders.
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Tuberculose/prevenção & controle , Tuberculose/transmissão , Criança , Controle de Doenças Transmissíveis , Política de Saúde , Promoção da Saúde/métodos , Humanos , Infectologia/tendências , Mycobacterium tuberculosis/metabolismo , Pobreza , Risco , Organização Mundial da SaúdeRESUMO
RATIONALE: Novel tuberculosis (TB) vaccines should be safe and effective in populations infected with Mycobacterium tuberculosis (M.tb) and/or HIV for effective TB control. OBJECTIVE: To determine the safety and immunogenicity of MVA85A, a novel TB vaccine, among M.tb- and/or HIV-infected persons in a setting where TB and HIV are endemic. METHODS: An open-label, phase IIa trial was conducted in 48 adults with M.tb and/or HIV infection. Safety and immunogenicity were analyzed up to 52 weeks after intradermal vaccination with 5 × 10(7) plaque-forming units of MVA85A. Specific T-cell responses were characterized by IFN-γ enzyme-linked immunospot and whole blood intracellular cytokine staining assays. MEASUREMENTS AND MAIN RESULTS: MVA85A was well tolerated and no vaccine-related serious adverse events were recorded. MVA85A induced robust and durable response of mostly polyfunctional CD4(+) T cells, coexpressing IFN-γ, tumor necrosis factor-α, and IL-2. Magnitudes of pre- and postvaccination T-cell responses were lower in HIV-infected, compared with HIV-uninfected, vaccinees. No significant effect of antiretroviral therapy on immunogenicity of MVA85A was observed. CONCLUSIONS: MVA85A was safe and immunogenic in persons with HIV and/or M.tb infection. These results support further evaluation of safety and efficacy of this vaccine for prevention of TB in these target populations.
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Vacinas contra a Tuberculose/uso terapêutico , Tuberculose Pulmonar/terapia , Vacinas Virais/uso terapêutico , Infecções Oportunistas Relacionadas com a AIDS/prevenção & controle , Adolescente , Adulto , Contagem de Linfócito CD4 , Feminino , Infecções por HIV/imunologia , Humanos , Imunidade Celular , Masculino , Pessoa de Meia-Idade , Vacinas contra a Tuberculose/efeitos adversos , Vacinas contra a Tuberculose/imunologia , Tuberculose Pulmonar/imunologia , Tuberculose Pulmonar/prevenção & controle , Vacinas de DNA , Carga Viral , Vacinas Virais/efeitos adversos , Vacinas Virais/imunologia , Adulto JovemRESUMO
The development of effective immunoprophylaxis against tuberculosis (TB) remains a global priority, but is hampered by a partially protective Bacillus Calmette-Guérin (BCG) vaccine and an incomplete understanding of the mechanisms of immunity to Mycobacterium tuberculosis. Although host genetic factors may be a primary reason for BCG's variable and inadequate efficacy, this possibility has not been intensively examined. We hypothesized that Toll-like receptor (TLR) variation is associated with altered in vivo immune responses to BCG. We examined whether functionally defined TLR pathway polymorphisms were associated with T cell cytokine responses in whole blood stimulated ex vivo with BCG 10 weeks after newborn BCG vaccination of South African infants. In the primary analysis, polymorphism TLR6_C745T (P249S) was associated with increased BCG-induced IFN-γ in both discovery (nâ=â240) and validation (nâ=â240) cohorts. In secondary analyses of the combined cohort, TLR1_T1805G (I602S) and TLR6_G1083C (synonymous) were associated with increased IFN-γ, TLR6_G1083C and TLR6_C745T were associated with increased IL-2, and TLR1_A1188T was associated with increased IFN-γ and IL-2. For each of these polymorphisms, the hypo-responsive allele, as defined by innate immunity signaling assays, was associated with increased production of TH1-type T cell cytokines (IFN-γ or IL-2). After stimulation with TLR1/6 lipopeptide ligands, PBMCs from TLR1/6-deficient individuals (stratified by TLR1_T1805G and TLR6_C745T hyporesponsive genotypes) secreted lower amounts of IL-6 and IL-10 compared to those with responsive TLR1/6 genotypes. In contrast, no IL-12p70 was secreted by PBMCs or monocytes. These data support a mechanism where TLR1/6 polymorphisms modulate TH1 T-cell polarization through genetic regulation of monocyte IL-10 secretion in the absence of IL-12. These studies provide evidence that functionally defined innate immune gene variants are associated with the development of adaptive immune responses after in vivo vaccination against a bacterial pathogen in humans. These findings could potentially guide novel adjuvant vaccine strategies as well as have implications for IFN-γ-based diagnostic testing for TB.
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Vacina BCG/imunologia , Receptor 1 Toll-Like/deficiência , Receptor 6 Toll-Like/deficiência , Tuberculose/prevenção & controle , Humanos , Lactente , Interferon gama/biossíntese , Interferon gama/genética , Interleucina-2/genética , Interleucina-6/genética , Mycobacterium bovis/imunologia , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/imunologia , Polimorfismo Genético , Receptor 1 Toll-Like/genética , Receptor 6 Toll-Like/genéticaRESUMO
There exists high quality evidence showing that interactive educational meetings and workshops can improve healthcare worker performance. This evidence formed the basis for establishing the annual African Vaccinology Course in 2005 at the University of Cape Town in South Africa. The course, which is designed to develop vaccinology expertise for Africa, covers relevant basic sciences pertaining to vaccine-preventable diseases such as epidemiology, immunology and microbiology; discusses specific vaccine-preventable diseases; provides information on vaccine safety, vaccination strategies and evaluation of vaccines; discusses new vaccines in the pipeline; and promotes vaccine advocacy. We hope that course alumni would become strong advocates for childhood immunisation in their respective countries. Such dedicated advocacy should contribute to reducing the time gap between the development of new vaccines and the formulation of policies enabling their introduction in African countries, as well as contributing to more equitable increase in immunisation coverage in our continent.
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Controle de Doenças Transmissíveis , Conhecimentos, Atitudes e Prática em Saúde , Vacinação/estatística & dados numéricos , Vacinas/administração & dosagem , África , Humanos , Programas de Imunização/normas , Programas Nacionais de SaúdeRESUMO
BACKGROUND: Rotavirus is a common cause of severe diarrheal disease in children worldwide. Ninety percent of the associated deaths occur in sub-Saharan Africa and South East Asia. Our aim was to review the prevalence of rotavirus infection in Africa over the past 30 years. METHODS: Eligible studies were identified from 3 Medline searches. Only studies including children <5 years of age that included >50 children and had an observational period >3 months were included. The data were analyzed during 3 periods (1976-1985, 1986-1995, and 1996-2006), as a summary (1976-2006), and by different study settings (ie, hospital, outpatient department, and combined). RESULTS: The initial search identified 206 studies from 27 countries during 1976-2006. The refined search yielded 101 studies, of which 58 (57%) were hospital based, 25 (25%) were outpatient studies, and 18 (18%) were combined. Rotavirus was detected in 25% (interquartile range, 16%-32%) of stool samples. Rotavirus was the most common agent identified in 73% of studies in which multiple diarrheal agents were determined. CONCLUSION: Rotavirus is an important cause of severe diarrheal disease in children <5 years of age in Africa. Clinical trials in South Africa and Malawi have shown that severe rotavirus disease is a vaccine-preventable entity in Africa.
Assuntos
Diarreia/epidemiologia , Diarreia/virologia , Infecções por Rotavirus/epidemiologia , África/epidemiologia , Pré-Escolar , Diarreia/mortalidade , Humanos , Incidência , Lactente , Fatores de TempoRESUMO
RATIONALE: Immunogenicity of new tuberculosis (TB) vaccines is commonly assessed by measuring the frequency and cytokine expression profile of T cells. OBJECTIVES: We tested whether this outcome correlates with protection against childhood TB disease after newborn vaccination with bacillus Calmette-Guérin (BCG). METHODS: Whole blood from 10-week-old infants, routinely vaccinated with BCG at birth, was incubated with BCG for 12 hours, followed by cryopreservation for intracellular cytokine analysis. Infants were followed for 2 years to identify those who developed culture-positive TB-these infants were regarded as not protected against TB. Infants who did not develop TB disease despite exposure to TB in the household, and another group of randomly selected infants who were never evaluated for TB, were also identified-these groups were regarded as protected against TB. Cells from these groups were thawed, and CD4, CD8, and γδ T cell-specific expression of IFN-γ, TNF-α, IL-2, and IL-17 measured by flow cytometry. MEASUREMENTS AND MAIN RESULTS: A total of 5,662 infants were enrolled; 29 unprotected and two groups of 55 protected infants were identified. There was no difference in frequencies of BCG-specific CD4, CD8, and γδ T cells between the three groups of infants. Although BCG induced complex patterns of intracellular cytokine expression, there were no differences between protected and unprotected infants. CONCLUSIONS: The frequency and cytokine profile of mycobacteria-specific T cells did not correlate with protection against TB. Critical components of immunity against Mycobacterium tuberculosis, such as CD4 T cell IFN-γ production, may not necessarily translate into immune correlates of protection against TB disease.