Dynamic in vitro gastric digestion of skimmed milk using the NERDT, an advanced human biomimetic digestion system.

The main objective of this study was to assess the ability of the NEar Real Digestive Tract (NERDT), a computer-controlled biomimetic in vitro digestion system that considers the biomechanics of the stomach, to reproduce physiologically relevant features of skimmed milk gastric digestion. A second objective was to evaluate the influence of pepsin on the gastric coagulation and emptying of milk proteins from experiments performed with and without pepsin. A mass balance model over the stomach, assuming a perfectly stirred reactor behaviour, has been developed. The results show that the NERDT can adequately reproduce the targeted kinetics of gastric acidification and emptying, with a sieving effect that naturally leads to a delayed emptying of caseins. Milk coagulated earlier and more chyme was emptied towards the end of the experiments in the presence of pepsin than without, hence illustrating the key influence of pepsin on the gastric coagulation of caseins and subsequent hydrolysis and emptying of dairy particles. Overall, this study shows that the NERDT can be adequately controlled to achieve desired gastric digestion conditions, and appears to be a very useful tool to further improve the knowledge of the gastric digestion behaviour of complex foods such as milk.

Development of a Plasmodium vivax malaria model for evaluating the effects of control strategies on the malaria burden in Democratic People's Republic of Korea.

Background: Plasmodium vivax malaria has been one of the most troublesome diseases in the Democratic People's Republic of Korea (DPRK). Given that a majority of malaria cases are concentrated near the demilitarized zone, concerted elimination efforts from both the Republic of Korea (ROK) and DPRK are essential for a malaria-free Korean Peninsula. This study assessed the impact of rapid diagnostic tests (RDTs) and tafenoquine on malaria incidence in DPRK. Methods: We patterned the current model structure from the previously developed Plasmodium vivax malaria dynamic transmission model for ROK. Model parameters were adjusted using demographic and climate data from malaria-risk areas in DPRK, and the model was calibrated to annual malaria incidences from 2014 to 2018 in DPRK, as reported by the World Health Organization. Subsequently, we estimated the preventable malaria cases over a decade after introducing RDTs and tafenoquine compared to using microscopy alone and primaquine, respectively. Sensitivity analysis was performed to account for uncertainty in model parameters. Results: When comparing RDTs to microscopy, a one-day reduction in diagnostic time due to the introduction of RDTs led to a reduction in malaria incidence by 26,235 cases (65.6%) over the next decade. With a two-day reduction, incidences decreased by 33,635 (84.1%). When comparing a single dose of tafenoquine with a 14-day primaquine regimen, the former prevented 1,222 (77.5%) relapse cases and 4,530 (11.3%) total cases over the years. Conclusion: The continuous and simultaneous implementation of RDTs and tafenoquine emerges as a potent strategy to considerably reduce malaria in DPRK.

Customized Visual Discrimination Digital Therapy According to Visual Field Defects in Chronic Stroke Patients.

BACKGROUND AND PURPOSE: Visual perceptual learning (VPL) may improve visual field defects (VFDs) after chronic stroke, but the optimal training duration and location remain unknown. This prospective study aimed to determine the efficacy of 8 weeks of VFD-customized visual discrimination training in improving poststroke VFDs. METHODS: Prospectively enrolled patients with poststroke VFDs initially received no training for 8 weeks (no-training phase). They subsequently underwent our customized VPL program that included orientation-discrimination tasks in individualized blind fields and central letter-discrimination tasks three times per week for 8 weeks (training phase). We analyzed the luminance detection sensitivity and deviation as measured using Humphrey visual field tests before and after the no-training and training phases. The vision-related quality of life was assessed at baseline and at a 16-week follow-up using the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25). RESULTS: Changes in mean total deviation (MTD) scores were greater during the training phase than during the no-training phase (defective hemifield, p=0.002; whole field, p=0.004). The MTD scores improved during the training phase (defective hemifield, p=0.004; whole field, p=0.016), but not during the no-training phase (defective hemifield, p=0.178; whole field, p=0.178). The difference between the improved and worsened areas (≥6 dB changes in luminance detection sensitivity) was greater during the training phase than during the no-training phase (p=0.009). The vision-specific social functioning subscore of the NEI-VFQ-25 improved after the 16-week study period (p=0.040). CONCLUSIONS: Our 8-week VFD-customized visual discrimination training protocol may effectively improve VFDs and vision-specific social functioning in chronic stroke patients.

Exploring the formation of surficial whey protein deposits under shear stress by rheofluidic approach.

Understanding how shear affects whey protein stability is crucial to deal with typical industrial issues occurring at the bulk solution/surface interface, such as fouling during heat treatments. However, at the state of the art, this effect remains unclear, contrary to that of temperature. This article presents a novel strategy to study the impact of shear rate and concentration on the accumulation of whey protein surficial deposits. It consists in applying a range of shear rates (0-200 s-1) at controlled temperature (65 °C) on whey protein solutions (5-10 wt%) by a parallel plate rheometer equipped with a glass disc, thus allowing the off-line characterization of the deposits by microscopy. Our results highlight an unequivocal effect of increasing shear stress. At 5 wt%, it fosters the formation of primary deposits (≈ 10 µm), whereas at 10 wt% it results in the development of complex branched structures (≈ 50 µm) especially for shear rates ranging from 140 s-1 to 200 s-1. Based on the classification by size of the observed populations, we discuss possible hypotheses for the deposit growth kinetics, involving the interplay of different physico-chemical protein-surface interactions and paving the way to future further investigations.

The epidemiologic and economic impact of varicella and herpes zoster vaccination in South Korea: A mathematical modelling study.

BACKGROUND: In South Korea, the National Immunization Program has included one-dose varicella vaccination for 1-year-olds since 2005. This study examines the potential impact of introducing a two-dose varicella vaccination for children, along with zoster vaccination for adults, using either the zoster vaccine live (ZVL) or recombinant zoster vaccine (RZV). METHODS: The investigation considered four strategies in a base case scenario. The first involved introducing zoster vaccination for 60-year-olds, with a 60 % coverage. The second strategy combined zoster vaccination with a second-dose varicella vaccination for 4-year-olds, with a 90 % coverage. An age-structured model spanning 50 years was employed, assuming a zoster vaccine catch-up campaign over the initial 5 years. Cost-effectiveness analyses were conducted, assessing incremental cost-effectiveness ratios (ICERs), incremental net monetary benefits (INMBs), and net loss under different ages at zoster vaccination (50, 60, 65, and 70 years) and varying willingness-to-pay (WTP) levels from ₩40 million ($34,998) to ₩84 million ($74,000). RESULTS: All strategies were cost-effective and significantly reduced herpes zoster (HZ) incidence, preventing approximately 3,077,000 to 7,609,000 cases, depending on the chosen strategy. The combined strategy prevented around 4,950,000 varicella and 653,000 HZ cases additionally. RZV outperformed ZVL by preventing twice as many HZ cases and offering greater QALY gains. However, ZVL was more cost-effective due to its lower cost. Probabilistic sensitivity analyses revealed that RZV became more cost-effective at higher WTP thresholds, exceeding ₩60.9 million ($53,193) in terms of ICER and ₩62.5 million ($54,591) for INMBs and net loss. The optimal age for zoster vaccination was 60 years concerning ICER but 50 years regarding INMB. CONCLUSIONS: Combining RZV with a two-dose varicella vaccination strategy reduced the disease burden and improved QALY more effectively, though ZVL remained more cost-effective at lower WTP levels. Decisions regarding vaccination policies should be balanced between the public health needs and WTP levels.

Comparison of check-all-that-apply and intensity rating in orange juice and yogurt studies.

This study compared check-all-that-apply (CATA) and rating methods using simple flavor foods and determined the discrimination ability of two consumer-based methods. Orange juice (simple flavor and liquid) and yogurt (simple flavor and semi-solid) samples were used. Six samples with different flavors and textures were evaluated for each food group. One hundred twenty consumers participated in each food session. CATA and rating were performed in two visits at weekly intervals. Consumers in each session distinguished the sample characteristics, and similar results were obtained using the CATA and rating methods. Although the number of characteristics with a significant difference in the rating method was relatively higher than that of CATA, some attributes with low frequency and intensity values may not have a significant effect on sample discrimination. Therefore, the types of questionnaire should be selected considering the test objectives and how similar the samples were. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01413-y.

Consumer acceptability and texture analysis of frozen dumplings using different cooking methods.

Four frozen dumplings were prepared using air-frying, microwaving, pan-frying, and steaming for consumer acceptability and texture perception measure. Cluster analysis was performed and two groups resulted. Neutral consumers who generally rated 'like slightly' and 'neither like nor dislike' were influenced by the combinations of dumpling and cooking methods. Dumpling likers who rated higher than 'like moderately' were influenced by cooking methods. When divided into clusters, each effect was significant. For dumplings, consumers preferred three products over one. Regarding cooking methods, neutral consumers preferred pan-frying and air-frying. However, dumpling likers preferred pan-frying. Chewy, soft, crisp, and sticky characteristics positively influenced on acceptability. In addition, dumpling shells and fillings were analyzed to measure crispness and firmness, respectively, using a texture analyzer. Cooking methods influenced skin crispness but dumplings influenced filling firmness. Although correlation was very low between consumer texture perception and analytical measure, using both would be beneficial in further understanding. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01389-9.

Prediction of effectiveness of universal rotavirus vaccination in Southwestern Vietnam based on a dynamic mathematical model.

Vaccinating young children against rotavirus (RV) is a promising preventive strategy against rotavirus gastroenteritis (RVGE). We evaluated the relative risk reduction of RVGE induced by universal vaccination in Vietnam through dynamic model analysis. We developed an age-stratified dynamic Vaccinated-Susceptible-Infectious-Recovered-Susceptible model to analyze RV transmission and assess vaccine effectiveness (VE). We assumed 3 different vaccine efficacies: 55%, 70%, and 85%. For model calibration, we used a database of patients under 5 years of age admitted to Ho Chi Minh No.1 Hospital with RVGE between January 2013 and December 2018. Assuming a vaccination rate of 95%, the number of RVGE hospitalizations after 5 years from universal RV vaccination decreased from 92,502 cases to 45,626 with 85% efficacy, to 54,576 cases with 70% efficacy, and to 63,209 cases with 55% efficacy. Additionally, RVGE hospitalizations after 10 years decreased from 177,950 to 89,517 with 85% efficacy and to 121,832 cases with 55% efficacy. The relative risk reductions of RVGE after 10 years were 49.7% with 85% efficacy, 40.6% with 70% efficacy, and 31.5% with 55% efficacy. The VE was 1.10 times (95% CI, 1.01-1.22) higher in the 4-months to 1-year-old age group than in the other age groups (P = 0.038), when applying 85% efficacy with 95% coverage. In conclusion, despite its relatively lower efficacy compared to high-income countries, RV vaccination remains an effective intervention in Southwestern Vietnam. In particular, implementing universal RV vaccination with higher coverage would result in a decrease in RVGE hospitalizations among Vietnamese children under 5 years of age.

Unravelling the Influence of Composition and Heat Treatment on Key Characteristics of Dairy Protein Powders Using a Multifactorial Approach.

The purpose of this study was to improve understanding of the structural and functional property changes that milk-protein concentrates undergo during production, particularly how the manufacturing route (heat treatment position and intensity), standardization (in osmosed water or ultrafiltrate permeate) and formulation (casein:whey protein (Cas:WP) ratio) influence the physico-chemical characteristics-hygroscopicity, particle size, sphericity, density and evolution of browning during storage. To obtain a comprehensive understanding of the parameters responsible for the distinctive characteristics of different powders, a multifactorial approach was adopted. Hygroscopicity depended mainly on the standardizing solution and to a lesser extent the Cas:WP ratio. The particle size of the heat-treated casein-dominant powders was up to 5 µm higher than for those that had had no heat treatment regardless of the standardizing solution, which also had no influence on the sphericity of the powder particles. The density of the powders increased up to 800 kg·m-3 with a reduced proportion of casein, and lactose and whey proteins participated in browning reactions during storage at 13 °C. In increasing order, the modality of heat treatment, the standardizing solution and the Cas:WP protein ratio influenced the key characteristics. This work is relevant for industrial applications to increase control over the functionalities of powdered products.

Factors Influencing the Repeated Transient Optical Droplet Vaporization Threshold and Lifetimes of Phase Change, Perfluorocarbon Nanodroplets.

Perfluorocarbon nanodroplets (PFCnDs) are sub-micrometer emulsions composed of a surfactant-encased perfluorocarbon (PFC) liquid and can be formulated to transiently vaporize through optical stimulation. However, the factors governing repeated optical droplet vaporization (ODV) have not been investigated. In this study, we employ high-frame-rate ultrasound (US) to characterize the ODV thresholds of various formulations and imaging parameters and identify those that exhibit low vaporization thresholds and repeatable vaporization. We observe a phenomenon termed "preconditioning", where initial laser pulses generate reduced US contrast that appears linked with an increase in nanodroplet size. Variation in laser pulse repetition frequency is found not to change the vaporization threshold, suggesting that "preconditioning" is not related to residual heat. Surfactants (bovine serum albumin, lipids, and zonyl) impact the vaporization threshold and imaging lifetime, with lipid shells demonstrating the best performance with relatively low thresholds (21.6 ± 3.7 mJ/cm2) and long lifetimes (t1/2 = 104 ± 21.5 pulses at 75 mJ/cm2). Physiological stiffness does not affect the ODV threshold and may enhance nanodroplet stability. Furthermore, PFC critical temperatures are found to correlate with vaporization thresholds. These observations enhance our understanding of ODV behavior and pave the way for improved nanodroplet performance in biomedical applications.

In vivo shear wave elasticity imaging for assessment of diaphragm function in muscular dystrophy.

Duchenne muscular dystrophy (DMD) causes patients to suffer from ambulatory disability and cardiorespiratory failure, the latter of which leads to premature death. Due to its role in respiration, the diaphragm is an important muscle for study. A common method for evaluating diaphragm function is ex vivo force testing, which only allows for an end point measurement. In contrast, ultrasound shear wave elastography imaging (US-SWEI) can assess diaphragm function over time; however, US-SWEI studies in dystrophic patients to date have focused on the limbs without preclinical studies. In this work, we used US-SWEI to estimate the shear wave speed (SWS) in diaphragm muscles of healthy (WT) mice, mdx mice, and mdx mice haploinsufficient for utrophin (mdx-utr) at 6 and 12 months of age. Diaphragms were then subjected to ex vivo force testing and histological analysis at 12 months of age. Between 6 and 12 months, a 23.8% increase in SWS was observed in WT mice and a 27.8% increase in mdx mice, although no significant difference was found in mdx-utr mice. Specific force generated by mdx-utr diaphragms was lower than that of WT diaphragms following twitch stimulus. A strong correlation between SWS and collagen deposition was observed, as well as between SWS and muscle fiber size. Together, these data demonstrate the ability of US-SWEI to evaluate dystrophic diaphragm functionality over time and predict the biochemical and morphological make-up of the diaphragm. Additionally, our results highlight the advantage of US-SWEI over ex vivo testing by obtaining longitudinal measurements in the same subject. STATEMENT OF SIGNIFICANCE: In DMD patients, muscles experience cycles of regeneration and degeneration that contribute to chronic inflammation and muscle weakness. This pathology only worsens with time and leads to muscle wasting, including in respiratory and cardiac muscles. Because respiratory failure is a major contributor to premature death in DMD patients, the diaphragm muscle is an important muscle to evaluate and treat over time. Currently, diaphragm function is assessed using ex vivo force testing, a technique that only allows measurement at sacrifice. In contrast, ultrasonography, particularly shear wave elasticity imaging (USSWEI), is a promising tool for longitudinal assessment; however, most US-SWEI in DMD patients aimed for limb muscles only with the absence of preclinical studies. This work broadens the applications of US-SWE imaging by demonstrating its ability to track properties and function of dystrophic diaphragm muscles longitudinally in multiple dystrophic mouse models.

Cost-Effectiveness of Age-Expanding Strategy of Latent Tuberculosis Infection Treatment in Household Contacts in South Korea.

PURPOSE: The strategy of latent tuberculosis infection (LTBI) treatment in household tuberculosis (TB) contacts has been expanding in South Korea. However, there is little evidence of the cost-effectiveness of LTBI treatment in patients over 35 years of age. This study aimed to evaluate the cost-effectiveness of LTBI treatment among household TB contacts in different age groups in South Korea. MATERIALS AND METHODS: An age-structured model of TB was developed based on the reports from the Korea Disease Control and Prevention Agency and the National Health Insurance Service. Quality-adjusted life-years (QALY) and the averted number of TB-related deaths were estimated along with discounted costs for a measure of incremental cost-effectiveness ratios. RESULTS: The number of cumulative active TB cases would decrease by 1564 and 7450 under the scenario of LTBI treatment for those aged <35 years and <70 years, respectively, relative to the no-treatment scenario. The treatment strategies for patients aged 0 to <35 years, <55 years, <65 years, and <70 years would add 397, 1482, 3782, and 8491 QALYs at a cost of $660, $5930, $4560, and $2530, respectively, per QALY. For the averted TB-related deaths, LTBI treatment targeting those aged 0 to <35 years, <55 years, <65 years, and <70 years would avert 7, 89, 155, and 186 deaths at a cost of $35900, $99200, $111100, and $115700 per deaths, respectively, in 20 years. CONCLUSION: The age-specific expansion policy of LTBI treatment not only for those under 35 years of age but also for those under 65 years of age among household contacts was cost-effective in terms of QALYs and averted TB deaths.

Mathematical Modeling of COVID-19 Transmission and Intervention in South Korea: A Review of Literature.

South Korea implemented interventions to curb the spread of the novel coronavirus disease 2019 (COVID-19) pandemic with discovery of the first case in early 2020. Mathematical modeling designed to reflect the dynamics of disease transmission has been shown to be an important tool for responding to COVID-19. This study aimed to review publications on the structure, method, and role of mathematical models focusing on COVID-19 transmission dynamics in Korea. In total, 42 papers published between August 7, 2020 and August 21, 2022 were studied and reviewed. This study highlights the construction and utilization of mathematical models to help craft strategies for predicting the course of an epidemic and evaluating the effectiveness of control strategies. Despite the limitations caused by a lack of available epidemiological and surveillance data, modeling studies could contribute to providing scientific evidence for policymaking by simulating various scenarios.

Ameliorative Effect of Ginsenoside Rg6 in Periodontal Tissue Inflammation and Recovering Damaged Alveolar Bone.

Periodontal disease is a chronic disease with a high prevalence, and in order to secure natural materials to prevent oral diseases, new materials that protect periodontal tissue from inflammation are being sought. Genes were identified using real-time quantitative polymerase chain reaction (RT-qPCR), and proteins were confirmed using Western blot. Dichlorodihydrofluorescein diacetate (DCF-DA) analysis was used, and the antibacterial effects were confirmed through Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) analysis. To confirm this effect in vivo, Sprague-Dawley rats, in which periodontitis was induced using ligation or Lipopolysaccharide of Porphyromonas gingivalis (PG-LPS), were used. In vitro experiments using human periodontal ligament (HPDL) cells stimulated with PG-LPS showed that Ginsenoside Rg6 (G-Rg6) had anti-inflammatory, antibacterial, antioxidant, and osteoblast differentiation properties. In vivo, G-Rg6 was effective in Sprague-Dawley rats in which periodontitis was induced using ligation or PG-LPS. Therefore, Ginsenoside Rg6 shows potential effectiveness in alleviating periodontitis.

Heat treatment of milk protein concentrates affects enzymatic coagulation properties.

Dairy ingredients with highly concentrated protein contents are high added value products with expanding market. The manufacture of such ingredients includes a succession of unit operations of which heat treatment is a key step to guarantee the microbial safety, that induces major changes in protein structures and thus ingredients functionalities. However, due to an incomplete understanding of phenomena taking place at high protein concentrations, shedding light on their mechanisms is a scientific challenge as well as an industrial need. In this study, the influence of heat treatment (74 °C/ 30 s) of highly concentrated milk protein systems (up to 20 % w/w) on protein denaturation/aggregation and enzymatic coagulation properties was studied using an original semi-industrial approach. 10 % w/w protein solutions constituted with whey protein and casein micelles at milk ratio, standardized in osmosed water or ultrafiltration permeate were used. These protein solutions were processed in different ways prior the manufacture of powders: heat treatment of the 10 % w/w protein solution before vacuum evaporation, heat treatment of the 20 % w/w protein solution after vacuum concentration, two consecutive heat treatments before and after vacuum evaporation. A fourth powder was prepared from unheated 10 % w/w protein solution. An increase in protein concentration led to a higher heat-induced protein denaturation. This phenomenon was reduced when increasing the lactose content. The effect of heat treatment on the extent of protein denaturation was not cumulative. At high protein concentration, interactions between κ-casein and whey protein were modified compared to milk, as mainly micelle-bound aggregates were formed at pH about 6.7. This phenomenon was enhanced at low ionic strength and lactose content. Our study showed that the enzymatic coagulation properties of reconstituted protein powders could be correlated with their physico-chemical compositions. An increase in protein denaturation disrupted the gel reorganization and led to the formation of weaker gels but did not interfere on the micelles aggregation phase and the early gelation. On the contrary, an increase in ionic strength and lactose content led to higher gel time.

Evaluation of Intervention Policies for the COVID-19 Epidemic in the Seoul/Gyeonggi Region through a Model Simulation.

PURPOSE: To evaluate the efficacy of intervention policies on coronavirus disease-19 (COVID-19) dissemination. MATERIALS AND METHODS: An age-structured compartmental model for the COVID-19 outbreak was proposed to predict the impact of control measures in the Seoul/Gyeonggi region. The model was calibrated based on actual data and realistic situations, including daily vaccine doses, proportion of delta variant cases, and confirmed cases by age. We simulated different scenarios for non-pharmaceutical interventions by varying social distancing and school attendance strategies. RESULTS: Two-step mitigation of social distancing without in-person classes would result in a rapid increase in confirmed cases up to 10000 but would keep severe cases within the manageable range of the health care system. The overall impact of taking down the distancing level by one step with twice the increase in contacts at school was comparable to the above scenario. Implementation of two-step mitigation of social distancing along with a two-fold increase in contacts among the school-age group would dramatically increase confirmed and severe cases by over 80000 and 100, respectively, as early as the beginning of December. This policy would cause the situation to spiral out of control, considering the scale of the response and time to prepare. On the other hand, the burden on the current healthcare system caused by two-step mitigation of social distancing and 40% increased contacts in the school-age group was manageable if prepared. CONCLUSION: A compromise between social distancing and school attendance policy and timely preparations for the spread of COVID-19 are required.

Heterogeneous impact of Covid-19 response on tuberculosis burden by age group.

Apart from the incidence and mortality caused by it, Coronavirus disease (COVID-19) has had a significant impact on other diseases. This study aimed to estimate the influences of COVID-19 pandemic on the incidence of tuberculosis (TB) and the number of TB-associated deaths in Republic of Korea. A dynamic compartment model incorporating age-structure was developed for studying TB transmission and progression using the Korean population data. After calibration with notification of incidence data from South Korea, the TB burden over 6 years (2020-2025) was predicted under the nine different scenarios. Under the scenario of strong social distancing and low-level health service disruption, new TB cases were reduced by 761 after 1 year in comparison to the baseline. However, in the elderly population, social distancing had little impact on TB incidence. On the other hand, the number of TB-related deaths mainly depends on the level of health service disruption for TB care. It was predicted that with a high degree of health service disruption, the number of TB-related deaths would increase up to 155 in 1 year and 80 percent of the TB-related deaths would be in the elderly population. The decrease of tuberculosis incidence is significantly affected by social distancing, which is owing to reduction of contacts. The impact of health service disruption is dominant on TB-related deaths, which occurs mainly in the elderly. It suggests that it is important to monitor TB-related deaths by COVID-19 because the TB burden of the elderly is high in the Republic of Korea.

Cost-Benefit Analysis of Tafenoquine for Radical Cure of Plasmodium vivax Malaria in Korea.

BACKGROUND: Plasmodium vivax malaria has a persistent liver stage that causes relapse, and introducing tafenoquine to suppress relapse could aid in disease eradication. Therefore, we assessed the impact of tafenoquine introduction on P. vivax malaria incidence and performed a cost-benefit analysis from the payer's perspective. METHODS: We expanded the previously developed P. vivax malaria dynamic transmission model and calibrated it to weekly civilian malaria incidences in 2014-2018. Primaquine and tafenoquine scenarios were considered by assuming different relapse probabilities, and relapse and total P. vivax malaria cases were predicted over the next decade for each scenario. We then estimated the number of cases prevented by replacing primaquine with tafenoquine. The cost and benefit of introducing tafenoquine were obtained using medical expenditure from a nationwide database, and a cost-benefit analysis was conducted. A probabilistic sensitivity analysis was performed to assess the economic feasibility robustness of tafenoquine introduction under uncertainties of model parameters, costs, and benefits. RESULTS: Under 0.04 primaquine relapse probability, the introduction of tafenoquine with relapse probability of 0.01 prevented 129 (12.27%) and 35 (77.78%) total and relapse cases, respectively, over the next decade. However, under the same relapse probability as primaquine, introducing tafenoquine had no additional preventative effect. The 14-day primaquine treatment cost was $3.71. The tafenoquine and the glucose-6-phosphate dehydrogenase rapid diagnostic testing cost $57.37 and $7.76, totaling $65.13. The average medical expenditure per malaria patient was estimated at $1444.79. The cost-benefit analysis results provided an incremental benefit-cost ratio (IBCR) from 0 to 3.21 as the tafenoquine relapse probability decreased from 0.04 to 0.01. The probabilistic sensitivity analysis showed an IBCR > 1, indicating that tafenoquine is beneficial, with a probability of 69.1%. CONCLUSION: Tafenoquine could reduce P. vivax malaria incidence and medical costs and bring greater benefits than primaquine.

Estimation of single-dose varicella vaccine effectiveness in South Korea using mathematical modeling.

In South Korea, despite the implementation of a universal single-dose vaccination program for children aged 12-15 months in 2005, the varicella incidence rate remains significant. Prior case-control studies have reported that currently used varicella vaccines are extremely inefficacious. We estimated vaccine effectiveness (VE) by fitting a dynamic transmission model to age-specific varicella incidence data from 2007 to 2015 and available vaccine coverage data. The initial vaccine efficacy and primary failure rates were estimated to be 61.1% and 38.9%, respectively. The average duration of protection was 21.4 years. The mean VE [(1-relative risk) %] for the simulated data of 2004-2014 birth cohorts decreased from 59.8% to 50.7% over 9 years. This mathematical modeling study demonstrated that the single-dose vaccine exhibits moderate effectiveness, and a high proportion of primary failure could be a main cause of breakthrough infections. Therefore, a two-dose vaccination strategy should be considered.