Browsing by Author "Channing, Liezl"

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    Cost-effectiveness analysis of MVA85 vaccine: a new TB vaccine candidate
    (2013) Channing, Liezl; Sinanovic, Edina
    Tuberculosis (TB) remains a major public health concern. The BCG vaccine is, currently, the only vaccine against TB and, although it provides some protection against disseminated forms of TB, its effectiveness in preventing primary infection and disease progression to pulmonary TB is highly varied. A number of potential new TB vaccine candidates have been identified and are, currently, undergoing clinical trials. One such candidate is MVA85A. This study aims to assess the potential cost-effectiveness of a new TB vaccine, the MVA85A vaccine. The study compares two TB vaccine strategies, from the perspective of the South African Government: i. BCG, given at birth, which is the current standard of care in South Africa; and ii BCG, given at birth, together with a booster vaccine (MVA85A) given at 4 months, which is the potential new strategy. The study employs Decision Analytical Modelling, through the use of a Markov model, to estimate the costs and outcomes of the two strategies. The cumulative costs and outcomes of each intervention are used to calculate the cost-effectiveness ratio (CER) (i.e. the cost per TB case averted and the cost per TB death averted) for each intervention. These two cost-effectiveness ratios are compared using an incremental cost-effectiveness ratio (ICER), which represents the additional cost per additional benefit received. The results of the cost-effectiveness analysis indicate that the MVA85A strategy is both more costly and more effective – there are fewer TB cases and deaths from TB – than BCG alone. The Government would need to spend an additional USD 1,105 for every additional TB case averted and USD 284,017 for every additional TB death averted. Given the disappointing results of the MVA85A vaccine clinical trial – showing an efficacy of only 17.3%, this study will predominantly contribute to establishing an efficacy threshold for future vaccines. Our research also contributes to the body of knowledge on economic evaluations involving new TB vaccines as - to the best of our knowledge - this is the first cost-effectiveness analysis conducted using trial data involving a novel TB vaccine and providing a direct comparison with BCG vaccination. Furthermore, it provides a standardized Markov model, which is relatively simple to adapt to local settings and, which could be used in the future, to estimate the potential cost-effectiveness of new TB vaccines in children between the ages of 0–10 years.
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    Modelling the cost-effectiveness of a new infant vaccine to prevent tuberculosis disease in children in South Africa
    (2014-09-16) Channing, Liezl; Sinanovic, Edina
    Abstract Background Tuberculosis remains the leading cause of death in South Africa. A number of potential new TB vaccine candidates have been identified and are currently in clinical trials. One such candidate is MVA85A. This study aimed to estimate the cost-effectiveness of adding the MVA85A vaccine as a booster to the BCG vaccine in children from the perspective of the South African government. Methods The cost-effectiveness was assessed by employing Decision Analytic Modelling, through the use of a Markov model. The model compared the existing strategy of BCG vaccination to a new strategy in which infants receive BCG and a booster vaccine, MVA85A, at 4 months of age. The costs and outcomes of the two strategies are estimated through modelling the vaccination of a hypothetical cohort of newborns and following them from birth through to 10 years of age, employing 6-monthly cycles. Results The results of the cost-effectiveness analysis indicate that the MVA85A strategy is both more costly and more effective – there are fewer TB cases and deaths from TB than BCG alone. The South African government would need to spend an additional USD 1,105 for every additional TB case averted and USD 284,017 for every additional TB death averted. The threshold analysis shows that, if the efficacy of the MVA85A vaccine was 41.3% (instead of the current efficacy of 17.3%), the two strategies would have the same cost but more cases of TB and more deaths from TB would be prevented by adding the MVA85A vaccine to the BCG vaccine. In this case, the government chould consider the MVA85A strategy. Conclusions At the current level of efficacy, the MVA85A vaccine is neither effective nor cost-effective and, therefore, not a good use of limited resources. Nevertheless, this study contributes to developing a standardized Markov model, which could be used, in the future, to estimate the potential cost-effectiveness of new TB vaccines compared to the BCG vaccine, in children between the ages of 0–10 years. It also provides an indicative threshold of vaccine efficacy, which could guide future development.