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1.
BMC Infect Dis ; 22(1): 45, 2022 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-35016628

RESUMO

BACKGROUND: While some evidence has been demonstrated the cost-effectiveness of routine hepatitis A vaccination in middle-income countries, the evidence is still limited in other settings including in South Africa. Given this, the evidence base around the cost of care for hepatitis A needs to be developed towards considerations of introducing hepatitis A vaccines in the national immunisation schedule and guidelines. OBJECTIVES: To describe the severity, clinical outcomes, and cost of hepatitis A cases presenting to two tertiary healthcare centers in Cape Town, South Africa. METHODS: We conducted a retrospective folder review of patients presenting with hepatitis A at two tertiary level hospitals providing care for urban communities of metropolitan Cape Town, South Africa. Patients included in this folder review tested positive for hepatitis A immunoglobulin M between 1 January 2008 and 1 March 2018. RESULTS: In total, 239 folders of hepatitis A paediatric patients < 15 years old and 212 folders of hepatitis A adult patients [Formula: see text] 15 years old were included in the study. Before presenting for tertiary level care, more than half of patients presented for an initial consultation at either a community clinic or general physician. The mean length of hospital stay was 7.45 days for adult patients and 3.11 days for paediatric patients. Three adult patients in the study population died as a result of hepatitis A infection and 29 developed complicated hepatitis A. One paediatric patient in the study population died as a result of hepatitis A infection and 27 developed complicated hepatitis A, including 4 paediatric patients diagnosed with acute liver failure. The total cost per hepatitis A hospitalisation was $1935.41 for adult patients and $563.06 for paediatric patients, with overhead costs dictated by the length of stay being the largest cost driver. CONCLUSION: More than 1 in every 10 hepatitis A cases (13.3%) included in this study developed complicated hepatitis A or resulted in death. Given the severity of clinical outcomes and high costs associated with hepatitis A hospitalisation, it is important to consider the introduction of hepatitis A immunisation in the public sector in South Africa to potentially avert future morbidity, mortality, and healthcare spending.


Assuntos
Hepatite A , Adolescente , Adulto , Criança , Análise Custo-Benefício , Hepatite A/epidemiologia , Humanos , Estudos Retrospectivos , África do Sul/epidemiologia , Vacinação
2.
BMC Med ; 18(1): 233, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32854714

RESUMO

BACKGROUND: An effective vaccine against Bordetella pertussis was introduced into the Expanded Programme on Immunisation (EPI) by WHO in 1974, leading to a substantial global reduction in pertussis morbidity and mortality. In low- and middle-income countries (LMICs), however, the epidemiology of pertussis remains largely unknown. This impacts negatively on pertussis control strategies in these countries. This study aimed to systematically and comprehensively review published literature on the burden of laboratory-confirmed pertussis in LMICs over the 45 years of EPI. METHODS: Electronic databases were searched for relevant literature (1974 to December 2018) using common and MeSH terms for pertussis. Studies using PCR, culture or paired serology to confirm Bordetella pertussis and parapertussis in symptomatic individuals were included if they had clearly defined numerators and denominators to determine prevalence and mortality rates. RESULTS: Eighty-two studies (49,167 participants) made the inclusion criteria. All six WHO regions were represented with most of the studies published after 2010 and involving mainly upper middle-income countries (n = 63; 77%). PCR was the main diagnostic test after the year 2000. The overall median point prevalence of PCR-confirmed Bordetella pertussis was 11% (interquartile range (IQR), 5-27%), while culture-confirmed was 3% (IQR 1-9%) and paired serology a median of 17% (IQR 3-23%) over the period. On average, culture underestimated prevalence by 85% (RR = 0.15, 95% CI, 0.10-0.22) compared to PCR in the same studies. Risk of pertussis increased with HIV exposure [RR, 1.4 (95% CI, 1.0-2.0)] and infection [RR, 2.4 (95% CI, 1.1-5.1)]. HIV infection and exposure were also related to higher pertussis incidences, higher rates of hospitalisation and pertussis-related deaths. Pertussis mortality and case fatality rates were 0.8% (95% CI, 0.4-1.4%) and 6.5% (95% CI, 4.0-9.5%), respectively. Most deaths occurred in infants less than 6 months of age. CONCLUSIONS: Despite the widespread use of pertussis vaccines, the prevalence of pertussis remains high in LMIC over the last three decades. There is a need to increase access to PCR-based diagnostic confirmation in order to improve surveillance. Disease control measures in LMICs must take into account the persistent significant infant mortality and increased disease burden associated with HIV infection and exposure.


Assuntos
Bordetella pertussis/patogenicidade , Programas de Imunização/métodos , Coqueluche/epidemiologia , Países em Desenvolvimento , Feminino , História do Século XX , Humanos , Masculino
3.
Cochrane Database Syst Rev ; 1: CD011895, 2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31978259

RESUMO

BACKGROUND: Adolescent vaccination has received increased attention since the Global Vaccine Action Plan's call to extend the benefits of immunisation more equitably beyond childhood. In recent years, many programmes have been launched to increase the uptake of different vaccines in adolescent populations; however, vaccination coverage among adolescents remains suboptimal. Therefore, understanding and evaluating the various interventions that can be used to improve adolescent vaccination is crucial. OBJECTIVES: To evaluate the effects of interventions to improve vaccine uptake among adolescents. SEARCH METHODS: In October 2018, we searched the following databases: CENTRAL, MEDLINE Ovid, Embase Ovid, and eight other databases. In addition, we searched two clinical trials platforms, electronic databases of grey literature, and reference lists of relevant articles. For related systematic reviews, we searched four databases. Furthermore, in May 2019, we performed a citation search of five other websites. SELECTION CRITERIA: Randomised trials, non-randomised trials, controlled before-after studies, and interrupted time series studies of adolescents (girls or boys aged 10 to 19 years) eligible for World Health Organization-recommended vaccines and their parents or healthcare providers. DATA COLLECTION AND ANALYSIS: Two review authors independently screened records, reviewed full-text articles to identify potentially eligible studies, extracted data, and assessed risk of bias, resolving discrepancies by consensus. For each included study, we calculated risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CI) where appropriate. We pooled study results using random-effects meta-analyses and assessed the certainty of the evidence using GRADE. MAIN RESULTS: We included 16 studies (eight individually randomised trials, four cluster randomised trials, three non-randomised trials, and one controlled before-after study). Twelve studies were conducted in the USA, while there was one study each from: Australia, Sweden, Tanzania, and the UK. Ten studies had unclear or high risk of bias. We categorised interventions as recipient-oriented, provider-oriented, or health systems-oriented. The interventions targeted adolescent boys or girls or both (seven studies), parents (four studies), and providers (two studies). Five studies had mixed participants that included adolescents and parents, adolescents and healthcare providers, and parents and healthcare providers. The outcomes included uptake of human papillomavirus (HPV) (11 studies); hepatitis B (three studies); and tetanus-diphtheria-acellular-pertussis (Tdap), meningococcal, HPV, and influenza (three studies) vaccines among adolescents. Health education improves HPV vaccine uptake compared to usual practice (RR 1.43, 95% CI 1.16 to 1.76; I² = 0%; 3 studies, 1054 participants; high-certainty evidence). In addition, one large study provided evidence that a complex multi-component health education intervention probably results in little to no difference in hepatitis B vaccine uptake compared to simplified information leaflets on the vaccine (RR 0.98, 95% CI 0.97 to 0.99; 17,411 participants; moderate-certainty evidence). Financial incentives may improve HPV vaccine uptake compared to usual practice (RR 1.45, 95% CI 1.05 to 1.99; 1 study, 500 participants; low-certainty evidence). However, we are uncertain whether combining health education and financial incentives has an effect on hepatitis B vaccine uptake, compared to usual practice (RR 1.38, 95% CI 0.96 to 2.00; 1 study, 104 participants; very low certainty evidence). Mandatory vaccination probably leads to a large increase in hepatitis B vaccine uptake compared to usual practice (RR 3.92, 95% CI 3.65 to 4.20; 1 study, 6462 participants; moderate-certainty evidence). Provider prompts probably make little or no difference compared to usual practice, on completion of Tdap (OR 1.28, 95% CI 0.59 to 2.80; 2 studies, 3296 participants), meningococcal (OR 1.09, 95% CI 0.67 to 1.79; 2 studies, 3219 participants), HPV (OR 0.99, 95% CI 0.55 to 1.81; 2 studies, 859 participants), and influenza (OR 0.91, 95% CI 0.61 to 1.34; 2 studies, 1439 participants) vaccination schedules (moderate-certainty evidence). Provider education with performance feedback may increase the proportion of adolescents who are offered and accept HPV vaccination by clinicians, compared to usual practice. Compared to adolescents visiting non-participating clinicians (in the usual practice group), the adolescents visiting clinicians in the intervention group were more likely to receive the first dose of HPV during preventive visits (5.7 percentage points increase) and during acute visits (0.7 percentage points for the first and 5.6 percentage points for the second doses of HPV) (227 clinicians and more than 200,000 children; low-certainty evidence). A class-based school vaccination strategy probably leads to slightly higher HPV vaccine uptake than an age-based school vaccination strategy (RR 1.09, 95% CI 1.06 to 1.13; 1 study, 5537 participants; moderate-certainty evidence). A multi-component provider intervention (including an education session, repeated contacts, individualised feedback, and incentives) probably improves uptake of HPV vaccine compared to usual practice (moderate-certainty evidence). A multi-component intervention targeting providers and parents involving social marketing and health education may improve HPV vaccine uptake compared to usual practice (RR 1.41, 95% CI 1.25 to 1.59; 1 study, 25,869 participants; low-certainty evidence). AUTHORS' CONCLUSIONS: Various strategies have been evaluated to improve adolescent vaccination including health education, financial incentives, mandatory vaccination, and class-based school vaccine delivery. However, most of the evidence is of low to moderate certainty. This implies that while this research provides some indication of the likely effect of these interventions, the likelihood that the effects will be substantially different is high. Therefore, additional research is needed to further enhance adolescent immunisation strategies, especially in low- and middle-income countries where there are limited adolescent vaccination programmes. In addition, it is critical to understand the factors that influence hesitancy, acceptance, and demand for adolescent vaccination in different settings. This is the topic of an ongoing Cochrane qualitative evidence synthesis, which may help to explain why and how some interventions were more effective than others in increasing adolescent HPV vaccination coverage.


Assuntos
Educação em Saúde/métodos , Vacinação/estatística & dados numéricos , Adolescente , Criança , Estudos Controlados Antes e Depois , Pessoal de Saúde/educação , Humanos , Pais/educação , Ensaios Clínicos Controlados Aleatórios como Assunto , Vacinação/tendências
4.
BMC Infect Dis ; 19(1): 651, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31331281

RESUMO

BACKGROUND: Hepatitis A, caused by the hepatitis A virus (HAV), is a vaccine preventable disease. In Low and Middle-Income Countries (LMICs), poor hygiene and sanitation conditions are the main risk factors contributing to HAV infection. There have been, however, notable improvements in hygiene and sanitation conditions in many LMICs. As a result, there are studies showing a possible transition of some LMICs from high to intermediate HAV endemicity. The World Health Organization (WHO) recommends that countries should routinely collect, analyse and review local factors (including disease burden) to guide the development of hepatitis A vaccination programs. Up-to-date information on hepatitis A burden is, therefore, critical in aiding the development of country-specific recommendations on hepatitis A vaccination. METHODS: We conducted a systematic review to present an up-to-date, comprehensive synthesis of hepatitis A epidemiological data in Africa. RESULTS: The main results of this review include: 1) the reported HAV seroprevalence data suggests that Africa, as a whole, should not be considered as a high HAV endemic region; 2) the IgM anti-HAV seroprevalence data showed similar risk of acute hepatitis A infection among all age-groups; 3) South Africa could be experiencing a possible transition from high to intermediate HAV endemicity. The results of this review should be interpreted with caution as the reported data represents research work with significant sociocultural, economic and environmental diversity from 13 out of 54 African countries. CONCLUSIONS: Our findings show that priority should be given to collecting HAV seroprevalence data and re-assessing the current hepatitis A control strategies in Africa to prevent future disease outbreaks.


Assuntos
Hepatite A/epidemiologia , África/epidemiologia , Surtos de Doenças , Hepatite A/mortalidade , Anticorpos Anti-Hepatite A/sangue , Hospitalização/estatística & dados numéricos , Humanos , Imunoglobulina M/sangue , Pobreza , Fatores de Risco , Saneamento , Estudos Soroepidemiológicos , África do Sul/epidemiologia
5.
Lancet ; 387(10035): 2312-2322, 2016 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-27017310

RESUMO

BACKGROUND: Identification of blood biomarkers that prospectively predict progression of Mycobacterium tuberculosis infection to tuberculosis disease might lead to interventions that combat the tuberculosis epidemic. We aimed to assess whether global gene expression measured in whole blood of healthy people allowed identification of prospective signatures of risk of active tuberculosis disease. METHODS: In this prospective cohort study, we followed up healthy, South African adolescents aged 12-18 years from the adolescent cohort study (ACS) who were infected with M tuberculosis for 2 years. We collected blood samples from study participants every 6 months and monitored the adolescents for progression to tuberculosis disease. A prospective signature of risk was derived from whole blood RNA sequencing data by comparing participants who developed active tuberculosis disease (progressors) with those who remained healthy (matched controls). After adaptation to multiplex quantitative real-time PCR (qRT-PCR), the signature was used to predict tuberculosis disease in untouched adolescent samples and in samples from independent cohorts of South African and Gambian adult progressors and controls. Participants of the independent cohorts were household contacts of adults with active pulmonary tuberculosis disease. FINDINGS: Between July 6, 2005, and April 23, 2007, we enrolled 6363 participants from the ACS study and 4466 from independent South African and Gambian cohorts. 46 progressors and 107 matched controls were identified in the ACS cohort. A 16 gene signature of risk was identified. The signature predicted tuberculosis progression with a sensitivity of 66·1% (95% CI 63·2-68·9) and a specificity of 80·6% (79·2-82·0) in the 12 months preceding tuberculosis diagnosis. The risk signature was validated in an untouched group of adolescents (p=0·018 for RNA sequencing and p=0·0095 for qRT-PCR) and in the independent South African and Gambian cohorts (p values <0·0001 by qRT-PCR) with a sensitivity of 53·7% (42·6-64·3) and a specificity of 82·8% (76·7-86) in the 12 months preceding tuberculosis. INTERPRETATION: The whole blood tuberculosis risk signature prospectively identified people at risk of developing active tuberculosis, opening the possibility for targeted intervention to prevent the disease. FUNDING: Bill & Melinda Gates Foundation, the National Institutes of Health, Aeras, the European Union, and the South African Medical Research Council.


Assuntos
Tuberculose/diagnóstico , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Expressão Gênica , Humanos , Pessoa de Meia-Idade , Mycobacterium tuberculosis/genética , Estudos Prospectivos , RNA Bacteriano/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Medição de Risco , Fatores de Risco , Tuberculose/sangue , Tuberculose/genética , Adulto Jovem
6.
BMC Med ; 14: 76, 2016 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-27183822

RESUMO

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.


Assuntos
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/imunologia
7.
Cochrane Database Syst Rev ; (8): CD009855, 2016 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-27510030

RESUMO

BACKGROUND: Governments use different approaches to ensure that private for-profit healthcare services meet certain quality standards. Such government guidance, referred to as public stewardship, encompasses government policies, regulatory mechanisms, and implementation strategies for ensuring accountability in the delivery of services. However, the effectiveness of these strategies in low- and middle-income countries (LMICs) have not been the subject of a systematic review. OBJECTIVES: To assess the effects of public sector regulation, training, or co-ordination of the private for-profit health sector in low- and middle-income countries. SEARCH METHODS: For related systematic reviews, we searched the Cochrane Database of Systematic Reviews (CDSR) 2015, Issue 4; Database of Abstracts of Reviews of Effectiveness (DARE) 2015, Issue 1; Health Technology Assessment Database (HTA) 2015, Issue 1; all part of The Cochrane Library, and searched 28 April 2015. For primary studies, we searched MEDLINE, Epub Ahead of Print, In-Process & Other Non-Indexed Citations, MEDLINE Daily and MEDLINE 1946 to Present, OvidSP (searched 16 June 2016); Science Citation Index and Social Sciences Citation Index 1987 to present, and Emerging Sources Citation Index 2015 to present, ISI Web of Science (searched 3 May 2016 for papers citing included studies); Cochrane Central Register of Controlled Trials (CENTRAL), 2015, Issue 3, part of The Cochrane Library (including the Cochrane Effective Practice and Organisation of Care (EPOC) Group Specialised Register) (searched 28 April 2015); Embase 1980 to 2015 Week 17, OvidSP (searched 28 April 2015); Global Health 1973 to 2015 Week 16, OvidSP (searched 30 April 2015); WHOLIS, WHO (searched 30 April 2015); Science Citation Index and Social Sciences Citation Index 1975 to present, ISI Web of Science (searched 30 April 2015); Health Management, ProQuest (searched 22 November 2013). In addition, in April 2016, we searched the reference lists of relevant articles, WHO International Clinical Trials Registry Platform, Clinicaltrials.gov, and various electronic databases of grey literature. SELECTION CRITERIA: Randomised trials, non-randomised trials, interrupted time series studies, or controlled before-after studies. DATA COLLECTION AND ANALYSIS: Two authors independently assessed study eligibility and extracted data, comparing their results and resolving discrepancies by consensus. We expressed study results as risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CI), where appropriate, and assessed the certainty of the evidence using Grades of Recommendation, Assessment, Development and Evaluation (GRADE). We did not conduct meta-analysis because of heterogeneity of interventions and study designs. MAIN RESULTS: We identified 20,177 records, 50 of them potentially eligible. We excluded 39 potentially eligible studies because they did not involve a rigorous evaluation of training, regulation, or co-ordination of private for-profit healthcare providers in LMICs; five studies identified after the review was submitted are awaiting assessment; and six studies met our inclusion criteria. Two included studies assessed training alone; one assessed regulation alone; three assessed a multifaceted intervention involving training and regulation; and none assessed co-ordination. All six included studies targeted private for-profit pharmacy workers in Africa and Asia.Three studies found that training probably increases sale of oral rehydration solution (one trial in Kenya, 106 pharmacies: RR 3.04, 95% CI 1.37 to 6.75; and one trial in Indonesia, 87 pharmacies: RR 1.41, 95% CI 1.03 to 1.93) and dispensing of anti-malarial drugs (one trial in Kenya, 293 pharmacies: RR 8.76, 95% CI 0.94 to 81.81); moderate-certainty evidence.One study conducted in the Lao People's Democratic Republic shows that regulation of the distribution and sale of registered pharmaceutical products may improve composite pharmacy indicators (one trial, 115 pharmacies: improvements in four of six pharmacy indicators; low-certainty evidence).The outcome in three multifaceted intervention studies was the quality of pharmacy practice; including the ability to ask questions, give advice, and provide appropriate treatment. The trials applied regulation, training, and peer influence in sequence; and the study design does not permit separation of the effects of the different interventions. Two trials conducted among 136 pharmacies in Vietnam found that the multifaceted intervention may improve the quality of pharmacy practice; but the third study, involving 146 pharmacies in Vietnam and Thailand, found that the intervention may have little or no effects on the quality of pharmacy practice (low-certainty evidence).Only two studies (both conducted in Vietnam) reported cost data, with no rigorous assessment of the economic implications of implementing the interventions in resource-constrained settings. No study reported data on equity, mortality, morbidity, adverse effects, satisfaction, or attitudes. AUTHORS' CONCLUSIONS: Training probably improves quality of care (i.e. adherence to recommended practice), regulation may improve quality of care, and we are uncertain about the effects of co-ordination on quality of private for-profit healthcare services in LMICs. The likelihood that further research will find the effect of training to be substantially different from the results of this review is moderate; implying that monitoring of the impact is likely to be needed if training is implemented. The low certainty of the evidence for regulation implies that the likelihood of further research finding the effect of regulation to be substantially different from the results of this review is high. Therefore, an impact evaluation is warranted if government regulation of private for-profit providers is implemented in LMICs. Rigorous evaluations of these interventions should also assess other outcomes such as impacts on equity, cost implications, mortality, morbidity, and adverse effects.


Assuntos
Países em Desenvolvimento , Pessoal de Saúde/educação , Serviços de Saúde/normas , Farmácias/normas , Setor Privado/normas , Regulamentação Governamental , Serviços de Saúde/legislação & jurisprudência , Humanos , Indonésia , Quênia , Laos , Farmácias/legislação & jurisprudência , Setor Privado/legislação & jurisprudência , Melhoria de Qualidade , Ensaios Clínicos Controlados Aleatórios como Assunto , Tailândia , Vietnã
8.
Lancet ; 381(9871): 1021-8, 2013 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-23391465

RESUMO

BACKGROUND: BCG vaccination provides incomplete protection against tuberculosis in infants. A new vaccine, modified Vaccinia Ankara virus expressing antigen 85A (MVA85A), was designed to enhance the protective efficacy of BCG. We aimed to assess safety, immunogenicity, and efficacy of MVA85A against tuberculosis and Mycobacterium tuberculosis infection in infants. METHODS: In our double-blind, randomised, placebo-controlled phase 2b trial, we enrolled healthy infants (aged 4­6 months) without HIV infection who had previously received BCG vaccination. We randomly allocated infants (1:1), according to an independently generated sequence with block sizes of four, to receive one intradermal dose of MVA85A or an equal volume of Candida skin test antigen as placebo at a clinical facility in a rural region near Cape Town, South Africa. We actively followed up infants every 3 months for up to 37 months. The primary study outcome was safety (incidence of adverse and serious adverse events) in all vaccinated participants, but we also assessed efficacy in a protocol-defined group of participants who received at least one dose of allocated vaccine. The primary efficacy endpoint was incident tuberculosis incorporating microbiological, radiological, and clinical criteria, and the secondary efficacy endpoint was M tuberculosis infection according to QuantiFERON TB Gold In-tube conversion (Cellestis, Australia). This trial was registered with the South African National Clinical Trials Register (DOH-27-0109-2654) and with ClinicalTrials.gov on July 31, 2009, number NCT00953927. FINDINGS: Between July 15, 2009, and May 4, 2011, we enrolled 2797 infants (1399 allocated MVA85A and 1398 allocated placebo). Median follow-up in the per-protocol population was 24·6 months (IQR 19·2­28·1), and did not differ between groups. More infants who received MVA85A than controls had at least one local adverse event (1251 [89%] of 1399 MVA85A recipients and 628 [45%] of 1396 controls who received the allocated intervention) but the numbers of infants with systemic adverse events (1120 [80%] and 1059 [76%]) or serious adverse events (257 [18%] and 258 (18%) did not differ between groups. None of the 648 serious adverse events in these 515 infants was related to MVA85A. 32 (2%) of 1399 MVA85A recipients met the primary efficacy endpoint (tuberculosis incidence of 1·15 per 100 person-years [95% CI 0·79 to 1·62]; with conversion in 178 [13%] of 1398 infants [95% CI 11·0 to 14·6]) as did 39 (3%) of 1395 controls (1·39 per 100 person-years [1·00 to 1·91]; with conversion in 171 [12%] of 1394 infants [10·6 to 14·1]). Efficacy against tuberculosis was 17·3% (95% CI −31·9 to 48·2) and against M tuberculosis infection was −3·8% (­28·1 to 15·9). INTERPRETATION: MVA85A was well tolerated and induced modest cell-mediated immune responses. Reasons for the absence of MVA85A efficacy against tuberculosis or M tuberculosis infection in infants need exploration. FUNDING: Aeras, Wellcome Trust, and Oxford-Emergent Tuberculosis Consortium (OETC).


Assuntos
Vacina BCG , Vacinas contra a Tuberculose/administração & dosagem , Tuberculose/prevenção & controle , Vacinas Virais/administração & dosagem , Antígenos de Bactérias/sangue , Antígenos de Bactérias/imunologia , Método Duplo-Cego , Feminino , Humanos , Lactente , Injeções Intradérmicas , Masculino , Mycobacterium tuberculosis , Resultado do Tratamento , Teste Tuberculínico , Tuberculose/imunologia , Vacinas contra a Tuberculose/efeitos adversos , Vacinas contra a Tuberculose/imunologia , Vacinas de DNA , Vacinas Virais/efeitos adversos , Vacinas Virais/imunologia
9.
Am J Respir Crit Care Med ; 188(4): 492-502, 2013 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-23306546

RESUMO

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).


Assuntos
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 Jovem
10.
BMC Health Serv Res ; 14: 52, 2014 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-24495533

RESUMO

BACKGROUND: Over the past four decades, extraordinary progress has been made in establishing and improving childhood immunization programmes around Africa. In order to ensure effective and sustainable positive growth of these childhood immunisations programmes, the development, adaptation and implementation of all interventions (programme activities, new vaccines, new strategies and policies) should be informed by the best available local evidence. METHODS: An assessment of the peer-reviewed literature on childhood immunization research published in English from 1970 to 2010 was conducted in PubMed and Africa-Wide databases. All study types were eligible for inclusion. A standard form was used to extract information from all studies identified as relevant and entered into a Microsoft Access database for analysis. RESULTS: Our initial search yielded 5436 articles from the two databases, from which 848 full text articles were identified as relevant. Among studies classified as clinical research (417), 40% were clinical trials, 24% were burden of disease/epidemiology and 36% were other clinical studies. Among studies classified as operational research (431), 77% related to programme management, 18% were policy related and 5% were related to vaccine financing. Studies were conducted in 48 African countries with six countries (South Africa, The Gambia, Nigeria, Senegal, Guinea-Bissau and Kenya) accounting for 56% of the total research output. Studies were published in 152 different journals with impact factors ranging from 0.192 to 53.29; with a median impact factor of 3.572. CONCLUSION: A similar proportion of clinical versus operational research output was found. However, an uneven distribution across Africa was observed with only six countries accounting for over half of the research output. The research conducted was of moderate to high quality, with 62% being published in journals with 2010 impact factors greater than two. Urgent attention should be given to the development of research capacity in low performing countries around Africa, with increased focus on the process of turning immunisations programme research evidence into policy and practice, as well as increased focus on issues relating to vaccine financing and sustainability in Africa.


Assuntos
Programas de Imunização/normas , África , Pesquisa Biomédica/normas , Pesquisa Biomédica/estatística & dados numéricos , Criança , Prática Clínica Baseada em Evidências , Pesquisa sobre Serviços de Saúde/normas , Pesquisa sobre Serviços de Saúde/estatística & dados numéricos , Humanos , Programas de Imunização/tendências , Vacinas/uso terapêutico
11.
BMC Med ; 11: 66, 2013 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-23497441

RESUMO

BACKGROUND: The implementation of strategic immunization plans whose development is informed by available locally-relevant research evidence should improve immunization coverage and prevent disease, disability and death in Africa. In general, health research helps to answer questions, generate the evidence required to guide policy and identify new tools. However, factors that influence the publication of immunization research in Africa are not known. We, therefore, undertook this study to fill this research gap by providing insights into factors associated with childhood immunization research productivity on the continent. We postulated that research productivity influences immunization coverage. METHODS: We conducted a bibliometric analysis of childhood immunization research output from Africa, using research articles indexed in PubMed as a surrogate for total research productivity. We used zero-truncated negative binomial regression models to explore the factors associated with research productivity. RESULTS: We identified 1,641 articles on childhood immunization indexed in PubMed between 1974 and 2010 with authors from Africa, which represent only 8.9% of the global output. Five countries (South Africa, Nigeria, The Gambia, Egypt and Kenya) contributed 48% of the articles. After controlling for population and gross domestic product, The Gambia, Guinea-Bissau and Sao Tome and Principe were the most productive countries. In univariable analyses, the country's gross domestic product, total health expenditure, private health expenditure, and research and development expenditure had a significant positive association with increased research productivity. Immunization coverage, adult literacy rate, human development index and physician density had no significant association. In the multivarable model, only private health expenditure maintained significant statistical association with the number of immunization articles. CONCLUSIONS: Immunization research productivity in Africa is highly skewed, with private health expenditure having a significant positive association. However, the current contribution of authors from Africa to global childhood immunization research output is minimal. The lack of association between research productivity and immunization coverage may be an indication of lack of interactive communication between health decision-makers, program managers and researchers; to ensure that immunization policies and plans are always informed by the best available evidence.


Assuntos
Bibliometria , Pesquisa Biomédica/tendências , Imunização/métodos , África , Humanos , Imunização/estatística & dados numéricos
12.
BMC Infect Dis ; 13: 566, 2013 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-24295439

RESUMO

BACKGROUND: Mobile phone text messaging (SMS) has the potential to promote adherence to tuberculosis treatment. This systematic review aims to synthesize current evidence on the effectiveness of SMS interventions in improving patients' adherence to tuberculosis treatment. METHODS: We searched electronic databases (PubMed, EMBASE, Science Citation Index), reference lists of relevant articles, conference proceedings, and selected websites for eligible studies available by 15 February 2013; regardless of language or publication status. Two authors independently screened selected eligible studies, and assessed risk of bias in included studies; resolving discrepancies by discussion and consensus. RESULTS: We identified four studies that compared the outcomes of the SMS intervention group with controls. Only one of the four studies was a randomized controlled trial. This was conducted in Argentina and the SMS intervention did not significantly improve adherence to tuberculosis treatment compared to self-administration of tuberculosis treatment (risk ratio [RR] 1.49, 95% confidence intervals [CI] 0.90 to 2.42). One of the non-randomized studies, conducted in South Africa, which compared SMS reminders to directly observed therapy short course (DOTS) reported similar rates of tuberculosis cure (62.35% vs. 66.4%) and treatment success (72.94% vs. 69.4%). A second study from South Africa, utilized SMS reminders when patients delayed in opening their pill bottles and reported increased tuberculosis cure (RR 2.32, 95% CI 1.60 to 3.36) and smear conversion (RR 1.62, 95% CI 1.09 to 2.42) rates compared to DOTS. In the third non-randomized study, conducted in Kenya, use of SMS reminders increased rates of clinic attendance on scheduled days compared to standard care (RR 1.56, 95% CI 1.06 to 2.29). Using the GRADE approach, we rate the quality of the evidence as low, mainly because of the high risk of bias and heterogeneity of effects across studies. CONCLUSIONS: This systematic review indicates that there is a paucity of high-quality data on the effectiveness of SMS interventions for improving patients' adherence to tuberculosis treatment. The low quality of the current evidence implies that further studies (in particular randomized trials) on the subject are needed. In the interim, if the intervention is implemented outside research settings an impact evaluation is warranted.


Assuntos
Adesão à Medicação , Envio de Mensagens de Texto , Tuberculose/tratamento farmacológico , Tuberculose/psicologia , Argentina , Telefone Celular/estatística & dados numéricos , Humanos , Quênia , Ensaios Clínicos Controlados Aleatórios como Assunto , África do Sul , Envio de Mensagens de Texto/estatística & dados numéricos
13.
Am J Respir Crit Care Med ; 186(10): 1051-6, 2012 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-22955316

RESUMO

RATIONALE: Conversions and reversions occur with IFN-γ release assay (IGRA) serial testing, as with the tuberculin skin test (TST). Recent TST conversion is associated with an established risk of developing tuberculosis (TB) disease, but the risk associated with recent IGRA conversions is unknown. OBJECTIVES: To compare the incidence rate of TB disease after recent QuantiFERON TB Gold In-Tube (QFT) conversion compared with nonconverters. METHODS: Adolescents with converted IGRA status (QFT converters [n = 534]) and randomly chosen adolescents whose IGRA status had remained negative over a period of 2 years (QFT nonconverters [n = 629]) were identified in a cohort study of TB infection and disease. Subsequent TB disease incidence was compared between the two groups. MEASUREMENTS AND MAIN RESULTS: For QFT converters, the TB incidence rate (all cases) was 1.46 cases per 100 person-years (95% confidence interval [CI], 0.82-2.39), and the cumulative incidence was 2.8% (95% CI, 1.58-4.59). A significantly lower TB incidence rate (0.17 cases per 100 person-yr [95% CI, 0.02-0.62]) and cumulative incidence (0.32% [95% CI, 0.03-1.14]) was observed for QFT nonconverters. The incidence rate ratio was 8.54 (95% CI, 2.51-29.13) for all cases of TB and 9.1 (95% CI, 1.65-50.36) for protocol-defined TB. CONCLUSIONS: Recent QFT conversion was indicative of an approximately eight fold higher risk of progression to TB disease (compared with nonconverters) within 2 years of conversion in a cohort of adolescents in a high-TB burden population.


Assuntos
Testes de Liberação de Interferon-gama , Tuberculose Latente/diagnóstico , Adolescente , Criança , Humanos , Valor Preditivo dos Testes , Teste Tuberculínico
14.
Am J Respir Crit Care Med ; 185(7): 769-78, 2012 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-22281831

RESUMO

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.


Assuntos
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 Jovem
15.
Ann Med ; 55(1): 2222641, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37345635

RESUMO

AIMS: The experience of Africa and the Middle East with the COVID-19 pandemic has been unique, which can be attributed, in part, to disparities within these regions. METHODS: This review describes COVID-19 emergence, epidemiology, vaccination strategies and uptake, and lessons learned within Africa and the Middle East. RESULTS: For vaccines to be effective in curtailing COVID-19, a global approach to vaccination is required. However, vaccine inequities exist in Africa and the Middle East, with countries with better healthcare infrastructure having advantages in acquiring and delivering vaccines. Currently, the greatest challenges to the effective rollout of COVID-19 vaccination in Africa and the Middle East are funding, healthcare resources, infrastructure, and vaccine access and hesitancy. While mechanisms to support vaccine access in low- and middle-income countries are initiated, their success has been limited and vaccine inequity is arguably the biggest hurdle to a successful response. The collection of surveillance data at both regional and global levels is also critical in response to the pandemic and provides the necessary tools and data to drive vaccine development. CONCLUSION: These considerations of the learnings can help refine the pandemic response and inform countries to better prepare for similar public health emergencies.


Learnings from previous epidemics enabled African nations to respond rapidly and cohesively to the emergence of the COVID-19 pandemic; similarly, nations in the Middle East also drew on previous outbreaks of other viruses to respond robustly, although perhaps less cohesively than the African nations.The populations of Africa and the Middle East share many of the same comorbidities (with the exception of HIV in Africa) and risk factors as other regions of the world, and both have experienced multiple waves of COVID-19 infections as new genetic variants of SARS-CoV-2 have evolved.African and Middle Eastern nations have had a wide range of success in vaccine rollout and uptake due to several factors including national wealth/income, populations with varying levels of vaccine hesitancy, and a range of access to private and/or public healthcare.Current challenges, some of which are being addressed by governmental and international entities, include a lack of vaccine- and surveillance-related infrastructure, needed improvement in regulatory standards, and persistent financial strains on healthcare systems that hinder improvements in vaccine delivery.


Assuntos
Vacinas contra COVID-19 , COVID-19 , Humanos , Vacinas contra COVID-19/uso terapêutico , Pandemias/prevenção & controle , COVID-19/epidemiologia , COVID-19/prevenção & controle , África/epidemiologia , Oriente Médio/epidemiologia
16.
BMC Infect Dis ; 12: 289, 2012 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-23130761

RESUMO

BACKGROUND: Each year more than two million people are newly infected with HIV worldwide, a majority of them through unprotected vaginal sex. More than half of new infections in adults occur in women. Male condoms and male circumcision reduce the risk of HIV acquisition; but the uptake of these methods is out of the control of women. We therefore aimed to determine the effectiveness of vaginal microbicides (a potential female-controlled method) for prevention of sexual acquisition of HIV in women. METHODS: We conducted a comprehensive search of peer-reviewed and grey literature for publications of randomised controlled trials available by September 2012. We screened search outputs, selected studies, assessed risk of bias, and extracted data in duplicate; resolving differences by discussion and consensus. RESULTS: We identified 13 eligible trials that compared vaginal microbicides to placebo. These studies enrolled 35,905 sexually active HIV-negative women between 1996 and 2011; in Benin, Cameroon, Cote d'Ivoire, Ghana, Kenya, Malawi, Nigeria, South Africa, Tanzania, Uganda, Zambia, Zimbabwe, India, Thailand, and the United States of America. A small trial of 889 women found that tenofovir (a nucleotide reverse transcriptase inhibitor) significantly reduces the risk of HIV acquisition (risk ratio [RR] 0.63, 95% confidence intervals [CI] 0.43 to 0.93). Effectiveness data are not yet available from follow-up tenofovir trials being conducted in South Africa, Uganda, and Zimbabwe (1 trial) and multiple sites in South Africa (1 trial). We found no evidence of a significant effect for nonoxynol-9 (5 trials), cellulose sulphate (2 trials), SAVVY (2 trials), Carraguard (1 trial), PRO 2000 (2 trials), and BufferGel (1 trial) microbicides. The pooled RR for the effect of current experimental vaginal microbicides on HIV acquisition in women was 0.97, 95%CI 0.87 to 1.08. Although study results were homogeneous across the different drug classes (heterogeneity P = 0.17, I2 = 27%), the overall intervention effect was not statistically significant. Nonoxynol-9 significantly increased the risk of having adverse genital lesions but no other microbicide led to significant increases in adverse events. CONCLUSIONS: There is not enough evidence at present to recommend vaginal microbicides for HIV prevention. Further high-quality research is needed to confirm the beneficial effects of tenofovir as well as continue the development and testing of new microbicides.


Assuntos
Anti-Infecciosos/administração & dosagem , Transmissão de Doença Infecciosa/prevenção & controle , Infecções por HIV/prevenção & controle , Administração Intravaginal , Adulto , Feminino , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto
17.
BMC Public Health ; 12: 578, 2012 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-22849711

RESUMO

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.


Assuntos
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 Sul
18.
J Infect Dis ; 203(12): 1832-43, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21606542

RESUMO

BACKGROUND: BCG, the only licensed tuberculosis vaccine, affords poor protection against lung tuberculosis in infants and children. A new tuberculosis vaccine, which may enhance the BCG-induced immune response, is urgently needed. We assessed the safety of and characterized the T cell response induced by 3 doses of the candidate vaccine, MVA85A, in BCG-vaccinated infants from a setting where tuberculosis is endemic. METHODS: Infants aged 5-12 months were vaccinated intradermally with either 2.5 × 10(7), 5 × 10(7), or 10 × 10(7) plaque-forming units of MVA85A, or placebo. Adverse events were documented, and T-cell responses were assessed by interferon γ (IFN-γ) enzyme-linked immunospot assay and intracellular cytokine staining. RESULTS: The 3 MVA85A doses were well tolerated, and no vaccine-related serious adverse events were recorded. MVA85A induced potent, durable T-cell responses, which exceeded prevaccination responses up to 168 d after vaccination. No dose-related differences in response magnitude were observed. Multiple CD4 T cell subsets were induced; polyfunctional CD4 T cells co-expressing T-helper cell 1 cytokines with or without granulocyte-macrophage colony-stimulating factor predominated. IFN-γ-expressing CD8 T cells, which peaked later than CD4 T cells, were also detectable. CONCLUSIONS: MVA85A was safe and induced robust, polyfunctional, durable CD4 and CD8 T-cell responses in infants. These data support efficacy evaluation of MVA85A to prevent tuberculosis in infancy. Clinical Trials Registration. NCT00679159.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Mycobacterium tuberculosis/imunologia , Vacinas contra a Tuberculose/imunologia , Tuberculose/prevenção & controle , Aciltransferases/imunologia , Fatores Etários , Antígenos de Bactérias/imunologia , Vacina BCG/imunologia , Linfócitos T CD8-Positivos/imunologia , Relação Dose-Resposta Imunológica , ELISPOT , Feminino , Humanos , Lactente , Interferon gama/metabolismo , Masculino , Placebos , Vacinas contra a Tuberculose/administração & dosagem , Vacinas contra a Tuberculose/efeitos adversos , Vacinas contra a Tuberculose/normas
19.
Eur J Immunol ; 40(1): 279-90, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20017188

RESUMO

Modified vaccinia Ankara-expressing Ag85A (MVA85A) is a new tuberculosis (TB) vaccine aimed at enhancing immunity induced by BCG. We investigated the safety and immunogenicity of MVA85A in healthy adolescents and children from a TB endemic region, who received BCG at birth. Twelve adolescents and 24 children were vaccinated and followed up for 12 or 6 months, respectively. Adverse events were documented and vaccine-induced immune responses assessed by IFN-gamma ELISpot and intracellular cytokine staining. The vaccine was well tolerated and there were no vaccine-related serious adverse events. MVA85A induced potent and durable T-cell responses. Multiple CD4+ T-cell subsets, based on expression of IFN-gamma, TNF-alpha, IL-2, IL-17 and GM-CSF, were induced. Polyfunctional CD4+ T cells co-expressing IFN-gamma, TNF-alpha and IL-2 dominated the response in both age groups. A novel CD4+ cell subset co-expressing these three Th1 cytokines and IL-17 was induced in adolescents, while a novel CD4+ T-cell subset co-expressing Th1 cytokines and GM-CSF was induced in children. Ag-specific CD8+ T cells were not detected. We conclude that in adolescents and children MVA85A safely induces the type of immunity thought to be important in protection against TB. This includes induction of novel Th1-cell populations that have not been previously described in humans.


Assuntos
Aciltransferases/imunologia , Antígenos de Bactérias/imunologia , Linfócitos T CD4-Positivos/imunologia , Vacinas contra a Tuberculose/imunologia , Tuberculose/imunologia , Tuberculose/prevenção & controle , Vaccinia virus/genética , Aciltransferases/genética , Adolescente , Antígenos de Bactérias/genética , Criança , Pré-Escolar , Feminino , Humanos , Memória Imunológica , Lactente , Masculino , Vacinas contra a Tuberculose/efeitos adversos
20.
Am J Respir Crit Care Med ; 181(12): 1407-17, 2010 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-20167847

RESUMO

RATIONALE: AERAS-402 is a novel tuberculosis vaccine designed to boost immunity primed by bacillus Calmette-Guérin (BCG), the only licensed vaccine. OBJECTIVES: We investigated the safety and immunogenicity of AERAS-402 in healthy Mycobacterium tuberculosis-uninfected BCG-vaccinated adults from a tuberculosis-endemic region of South Africa. METHODS: Escalating doses of AERAS-402 vaccine were administered intramuscularly to each of three groups of healthy South African BCG-vaccinated adults, and a fourth group received two injections of the maximal dose. Participants were monitored for 6 months, with all adverse effects documented. Vaccine-induced CD4(+) and CD8(+) T-cell immunity was characterized by an intracellular cytokine staining assay of whole blood and peripheral blood mononuclear cells. MEASUREMENTS AND MAIN RESULTS: AERAS-402 was well tolerated, and no vaccine-related serious adverse events were recorded. The vaccine induced a robust CD4(+) T-cell response dominated by cells coexpressing IFN-gamma, tumor necrosis factor-alpha, and IL-2 ("polyfunctional" cells). AERAS-402 also induced a potent CD8(+) T-cell response, characterized by cells expressing IFN-gamma and/or tumor necrosis factor-alpha, which persisted for the duration of the study. CONCLUSIONS: Vaccination with AERAS-402 is safe and immunogenic in healthy adults. The immunity induced by the vaccine appears promising: polyfunctional T cells are thought to be important for protection against intracellular pathogens such as Mycobacterium tuberculosis, and evidence is accumulating that CD8(+) T cells are also important. AERAS-402 induced a robust and durable CD8(+) T-cell response, which appears extremely promising. Clinical trial registered with www.sanctr.gov.za (NHREC no. 1381).


Assuntos
Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/efeitos dos fármacos , Vacinas contra a Tuberculose/uso terapêutico , Adulto , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Ativação Linfocitária/imunologia , Masculino , África do Sul , Vacinas contra a Tuberculose/imunologia , Vacinas de DNA , Adulto Jovem
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