Browsing by Author "Hussey, Gregory D."
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Item A bibliometric Analysis of Cancer Research in South Africa: study protocol(BMJ open, 2015) Moodley, Jennifer; Singh, Vedantha; Kagina, Benjamin M.; Abdullahi, Leila; Hussey, Gregory D.Cancer is an important and growing public health burden in South Africa (SA). Over the past few decades, there has been considerable scientific activity in cancer in SA. However, there has been limited analysis of cancer scientific publications. In this paper, we present a protocol for bibliometric analysis of cancer research conducted in SA. A comprehensive search of the journal databases PubMed, SCOPUS, Web of Science and EBSCO will be conducted to identify and retrieve data from primary peer-reviewed cancer research articles using a set of consensus search words. Articles that involve cancer research conducted in SA or using biological or clinical data from South African participants and published between 2004 and 2014 will be included in the study. Two independent researchers will screen the articles for eligibility. Bibliometric indicators and study characteristics will be extracted, entered into a database and analysed. The cancer disease site will be recorded and research will be classified using the Common Scientific Outline system. Data obtained will be analysed to determine SA's publication productivity index in cancer research. Annual trends in bibliometric indicators and the type of cancer research will be determined. The degree of collaboration in research conducted in SA will be analysed using co-authorship matrix software. A publication to disease type ratio will be used to assess scientific production relative to disease burden.Item Characterisation of the Environmental Presence of Hepatitis A Virus in Low-Income and Middle-Income Countries: A Systematic Review and Meta-Analysis(BMJ open, 2020) Kuodi, Paul; Patterson, Jenna; Hussey, Gregory D.; Kagina, Benjamin M.A total of 2092 records were retrieved, of which 33 met the inclusion criteria. 21 studies were conducted in Tunisia, India and South Africa, and the rest were from Philippines, Pakistan, Morocco, Chad, Mozambique, Kenya and Uganda. In Tunisian raw sewage samples, the prevalence of HAV ranged from 12% to 68%, with an estimated average detection rate of 50% (95% CI 25 to 75), whereas HAV detection in treated sewage in Tunisia ranged from 23% to 65%, with an estimated average detection rate of 38% (95% CI 20 to 57). The prevalence of HAV detection in South African treated sewage and surface water samples ranged from 4% to 37% and from 16% to 76%, with an estimated average detection rates of 15% (95% CI 1 to 29) and 51% (95% CI 21 to 80), respectively. Over the review period, the estimated average detection rate of environmental HAV presence appeared to have declined by 10%. The quality of included studies was fair, but sampling issues and paucity of data limited the strength of the review findings.Item Comparison of Adverse Events Following Immunisation with acellular and Whole-Cell Pertussis Vaccines: A Systematic Review(Vaccine, 2018) Patterson, Jenna; Kagina, Benjamin M.; Hussey, Gregory D.; Muloiwa, RudzaniTwo types of vaccines are currently licensed for use against pertussis: whole-cell (wP) and acellular pertussis (aP). There is evidence that wP confers more durable immunity than aP, however wP has been more frequently associated with adverse events following immunisation (AEFI). A comparison of the frequency of AEFI with the first doses of wP and aP has not yet been clearly documented. This must be done in light of recent considerations to move towards a wP prime-aP boost vaccination strategy in low and middle-income countries. To compare the frequency of AEFI associated with the first dose of the wP and aP vaccines. We also compared the frequency of AEFI associated with subsequent doses of wP. This systematic review was carried out in strict accordance with the published protocol. High heterogeneity amongst included one-armed studies did not allow for pooling of prevalence estimates. The prevalence estimates of AEFI at first vaccine dose of wP ranged from 0 to 75%, while the prevalence estimates of AEFI at first vaccine dose of aP ranges from 0 to 39%. The prevalence estimates of adverse events following second and third vaccine dose of wP ranged from 0 to 71% and 0 to 61%, respectively. Risk ratios among two-armed studies showed an increased risk of adverse events with first dose of wP compared to aP [local reaction RR 2.73 (2.33, 3.21), injection site pain RR 4.15 (3.24, 5.31), injection site swelling RR 4.38 (2.70, 7.12), fever over 38 °C RR 9.21 (5.39, 15.76), drowsiness RR 1.34 (1.18, 1.52) and vomiting RR 1.28 (0.91, 1.79)]. Our results confirm that, when comparing the first dose, wP is more reacotgenic than aP. The proposed wP prime followed by aP boost pertussis vaccine strategy should be approached with caution.Item Comparison of School based and Supplemental Vaccination Strategies in the Delivery of Vaccines to 5-19 year olds in Africa(F1000Research, 2017) Haddison, Eposi C.; Abdullahi, Leila H.; Hussey, Gregory D.; Kagina, Benjamin M.Some vaccine preventable diseases (VPDs) still remain a public health burden in many African countries. The occurrence of VPDs in all age groups has led to the realization of the need to extend routine immunisation services to school age children, adolescents and adults. Supplemental immunisation activities (SIAs) and school based vaccinations (SBVs) are common strategies used to complement the expanded programme on immunisation (EPI). This review aimed to assess the effectiveness of SIAs compared to SBVs in the administration of vaccines to 5-19 year olds in Africa. Systematic review methods were used to address our study aim. Several electronic databases were searched up to March 30, 2017 for primary studies investigating the delivery of vaccines via SIAs or SBVs to 5-19 year olds. This search was complemented by browsing reference lists of potential studies obtained from search outputs. Outcomes considered for inclusion were: vaccination coverage, costs of the strategy or its effect on routine immunisation services. Out of the 4938 studies identified, 31 studies met the review inclusion criteria. Both SIAs and SBVs showed high vaccination coverage. However, the SIAs reported higher coverage than SBVs: 91% (95% CI: 84%, 98%) versus 75% (95% CI: 67%, 83%). In most settings, SBVs were reported to be more expensive than SIAs. The SIAs were found to negatively affect routine immunisation services. Both SIAs and SBVs are routinely used to complement the EPI in the delivery of vaccines in Africa. In settings where school enrolment is suboptimal, as is the case in many African countries, our results show SIAs may be more effective in reaching school age children and adolescents than SBVs. Our results re-iterate the importance of evaluating systematic evidence to best inform African authorities on the optimal vaccine delivery strategies targeting school age children and adolescents.Item Epidemiology of Hepatitis A virus in Africa among Persons Aged 1–10 years: a systematic review protocol(Systematic Reviews, 2015) Kanyenda, Tiwonge J.; Abdullahi, Leila H.; Hussey, Gregory D.; Kagina, Benjamin M.Africa is considered an area of high endemicity for hepatitis A virus infection. However, in the past two decades, tremendous progress has been made in improving water sources and sanitation which are risk factors for hepatitis A virus infection. Recent studies suggest that several African countries could be in epidemiological transitions due to the evident socio-economic development. As a result, there may be a decrease in the exposure to and infection with hepatitis A virus at an early age. Understanding and mapping the shifting epidemiology is vital in developing control measures against the disease. We are conducting a comprehensive systematic review study to document the current burden of hepatitis A virus infection in Africa.Item The novel tuberculosis vaccine, AERAS-402, is safe in healthy infants previously vaccinated with BCG, and induces dose-dependent CD4 and CD8T cell response(Vaccine, 2014) Kagina, Benjamin M.N.; Tameris, Michele D.; Hussey, Gregory D.; Benko, JacquelineEfforts to reduce risk of tuberculosis disease in children include development of effective vaccines. Our aim was to test safety and immunogenicity of the new adenovirus 35-vectored tuberculosis vaccine candidate AERAS-402 in infants, administered as a boost following a prime with the Bacille Calmette-Guerin vaccine. In a phase 1 randomised, double-blind, placebo-controlled, dose-escalation trial, BCG-vaccinated infants aged 6–9 months were sequentially assigned to four study groups, then randomized to receive an increasing dose-strength of AERAS-402, or placebo. The highest dose group received a second dose of vaccine or placebo 56 days after the first. The primary study outcome was safety. Whole blood intracellular cytokine staining assessed immunogenicity. Forty-two infants received AERAS-402 and 15 infants received placebo. During follow-up of 182 days, an acceptable safety profile was shown with no serious adverse events or discontinuations related to the vaccine. AERAS-402 induced a specific T cell response. A single dose of AERAS-402 induced CD4T cells predominantly expressing single IFN-γ whereas two doses induced CD4T cells predominantly expressing IFN-γ, TNF-α and IL-2 together. CD8T cells were induced and were more likely to be present after 2 doses of AERAS-402. AERAS-402 was safe and immunogenic in healthy infants previously vaccinated with BCG at birth. Administration of the highest dose twice may be the most optimal vaccination strategy, based on the induced immunity. Multiple differences in T cell responses when infants are compared with adults vaccinated with AERAS-402, in the same setting and using the same whole blood intracellular cytokine assay, suggest specific strategies may be important for vaccination for each population.Item Safety of Licensed Vaccines in HIV-Infected Persons: A Systematic Review Protocol(Systematic reviews, 2014) Kagina, Benjamin M.; Wiysonge, Charles S.; Hussey, Gregory D.Safety of vaccines remains a cornerstone of building public trust on the use of these cost-effective and life-saving public health interventions. In some settings, particularly Sub-Saharan Africa, there is a high prevalence of HIV infection and a high burden of vaccine-preventable diseases. There is evidence suggesting that the immunity induced by some commonly used vaccines is not durable in HIV-infected persons, and therefore, repeated vaccination may be considered to ensure optimal vaccine-induced immunity in this population. However, some vaccines, particularly the live vaccines, may be unsafe in HIV-infected persons. There is lack of evidence on the safety profile of commonly used vaccines among HIV-infected persons. We are therefore conducting a systematic review to assess the safety profile of routine vaccines administered to HIV-infected persons.Item Systematic Review of the Global Epidemiology of Viral-induced Acute Liver Failure(BMJ open, 2020) Patterson, Jenna; Silal, Sheetal; Setshedi, Mashiko; Hussey, Gregory D.; Kagina, Benjamin M.; Muloiwa, RudzaniThe aetiology and burden of viral-induced acute liver failure remains unclear globally. It is important to understand the epidemiology of viral-induced ALF to plan for clinical case management and case prevention. Immunisation against hepatitis A and hepatitis B should be prioritised in low-income and middle-income countries to prevent high viral-induced acute liver failure mortality rates, especially in settings where resources for managing acute liver failure are lacking. The expanded use of hepatitis E immunisation should be explored as hepatitis E virus was the most common cause of acute liver failure.Item The Use of Supplementary Immunisation Activities to Improve Uptake of Current and Future Vaccines in Low-Income and Middle-Income Countries: A Systematic Review Protocol(BMJ open, 2014) Kagina, Benjamin M.; Wiysonge, Charles S.; Abdullahi, Leila H.; Uthman, Olalekan A.; Hussey, Gregory D.Immunisation coverage data in low-income and middle-income countries (LMICs) suggest that more strategies need to be implemented to achieve and sustain optimal vaccine uptake. Among possible strategies to improve immunisation coverage are supplementary immunisation activities (SIAs). We are therefore interested in conducting a systematic review to assess whether SIAs complement routine immunisation programmes to improve vaccination coverage and prevent disease outbreaks. Our systematic review will focus on studies conducted in LMICs. With the help of an information specialist, we will search for eligible studies in PubMed, Web of Science, Scopus, Africa-Wide, Cochrane Library, WHOLIS, CINAHL, PDQ-Evidence as well as reference lists of relevant publications. Additionally, we will contact relevant organisations such as WHO and GAVI. Two authors will independently extract data from eligible studies and independently assess risk of bias by assessing the adequacy of study characteristics. The primary meta-analysis will use random effects models due to expected interstudies heterogeneity. Dichotomous data will be analysed using relative risk and continuous data using weighted mean differences (or standardised mean differences), both with 95% CIs. The findings from this systematic review will be discussed in the context of strengthening routine childhood immunisation services, routine adolescent immunisation services and introduction of future vaccines against tuberculosis and HIV/AIDS.