Browsing by Author "Chen, Sheng-I"

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A stochastic programming model of vaccine preparation and administration for seasonal influenza interventions
(2020-01-01)
Chen, Sheng-I
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Wu, Chia-Yuan
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工業工程與管理學系
;
Department of Industrial Engineering and Management
This study considers the integration of vaccine preparation and administration decisions for seasonal influenza interventions. We examine actual vaccination activities of sharing multiple vaccine products and supplementary vaccinations. A two-stage stochastic program is formulated to determine the optimal ordering and allocation of vaccines under uncertain attack rates, vaccine efficacies, and demands. We present an algorithm based on the sample average approximation and warm-start solution to solve the stochastic integer program with continuous random variables. Furthermore, the optimal solution for the deterministic model using the expected value is analyzed and obtained directly. Our analysis compares the deterministic and stochastic solutions to assess the impact of uncertainties on the immunization outcomes and costs. The result shows that the stochastic programming model provides a more robust solution than the deterministic model, and uncertain characteristics should consider when making public health decisions.
Chemoprevention by means of soy proteins and peptides - current status and future approaches: a review
(2019-05-01)
Chen, Sheng-I
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Hsieh, Chia-Chien
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工業工程與管理學系
;
Department of Industrial Engineering and Management
Epidemiological studies have shown that soy consumption is associated with lower incidence of various diseases, such as cancer. Over the past decades, soy proteins and derived peptides have been considered as potential preventive agents against the initiation, promotion and progression of cancer. Additionally, soybeans provide essential nutrients and abundant peptides and proteins with multiple bioactivities. Here, we specifically emphasise the chemoprevention property of several soy proteins/peptides, such as lectins, lunasin and protease inhibitors. Moreover, their anti-inflammatory and antioxidant properties, which have been demonstrated to be associated with chemopreventive properties, are addressed here. Furthermore, computational methods applied in this field are reviewed. Researchers navigate a large volume of data to understand the interactions among the genome, cellular molecules, dietary interventions, medical treatments and diseases. Numerous powerful tools have been recommended for designing an optimal strategy for future anti-cancer treatments with precise diagnosis and individualised approaches.
Economic benefits of sharing and redistributing influenza vaccines when shortages occurred
(2017-10-17)
Chen, Sheng-I
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工業工程與管理學系
;
Department of Industrial Engineering and Management
Background Recurrent influenza outbreak has been a concern for government health institutions in Taiwan. Over 10% of the population is infected by influenza viruses every year, and the infection has caused losses to both health and the economy. Approximately three million free vaccine doses are ordered and administered to high-risk populations at the beginning of flu season to control the disease. The government recommends sharing and redistributing vaccine inventories when shortages occur. While this policy intends to increase inventory flexibility, and has been proven as widely valuable, its impact on vaccine availability has not been previously reported. Material and methods This study developed an inventory model adapted to vaccination protocols to evaluate government recommended polices under different levels of vaccine production. Demands were uncertain and stratified by ages and locations according to the demographic data in Taiwan. Results When vaccine supply is sufficient, sharing pediatric vaccine reduced vaccine unavailability by 43% and overstock by 54%, and sharing adult vaccine reduced vaccine unavailability by 9% and overstock by 15%. Redistributing vaccines obtained greater gains for both pediatrics and adults (by 75%). When the vaccine supply is in short, only sharing pediatric vaccine yielded a 48% reduction of unused inventory, while other polices do not improve performances. Conclusions When implementing vaccination activities for seasonal influenza intervention, it is important to consider mismatches of demand and vaccine inventory. Our model confirmed that sharing and redistributing vaccines can substantially increase availability and reduce unused vaccines.
Optimizing influenza vaccine policies for controlling 2009-like pandemics and regular outbreaks
(2019-01-28)
Chen, Sheng-I
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Wu, Chia-Yuan
;
Wu, Yu-Hsuan
;
Hsieh, Min-Wei
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工業工程與管理學系
Background. This study examined the effectiveness of various vaccine policies against influenza. The transmission rate was calculated by use of the time-series influenza-like illness case during the year of 2009 and recent epidemics in Taiwan. Methods. We developed a stochastic compartmental model to analyze the transmission of influenza, where the population was stratified by location and age group, and the vaccine distribution was considered using the current policy. The simulation study compared the previous vaccine policy and a new policy with expanded coverage and various lengths of the vaccination campaign. The sensitivity analysis investigated different levels of vaccine efficacy to confirm the robustness of the recommended policies. Results. Doubling vaccine coverage can decrease the number of infections effectively in the regular epidemic scenario. However, a peak of infections occurs if the duration of implementing vaccination is too long. In the 2009-like pandemic scenario, both increasing vaccine doses and reducing the program's duration can mitigate infections, although the early outbreak restricts the effectiveness of vaccination programs. Conclusions. The finding indicates that only increasing vaccine coverage can reduce influenza infections. To avoid the peak of infections, it is also necessary to execute the vaccination activity immediately. Vaccine efficacy significantly impacts the vaccination policy's performance. When vaccine efficacy is low, neither increasing vaccination doses nor reducing vaccination timeframe prevents infections. Therefore, the variation in vaccine efficacy should be taken into account when making immunization policies against influenza.
Why are women with obesity more likely to develop breast cancer
(2018-07-01)
Chen, Sheng-I
;
Hsieh, Chia-Chien
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工業工程與管理學系
;
Department of Industrial Engineering and Management