Proof of concept for a new sensor to monitor marine litter from space.

Worldwide, governments are implementing strategies to combat marine litter. However, their effectiveness is largely unknown because we lack tools to systematically monitor marine litter over broad spatio-temporal scales. Metre-sized aggregations of floating debris generated by sea-surface convergence lines have been reported as a reliable target for detection from satellites. Yet, the usefulness of such ephemeral, scattered aggregations as proxy for sustained, large-scale monitoring of marine litter remains an open question for a dedicated Earth-Observation mission. Here, we track this proxy over a series of 300,000 satellite images of the entire Mediterranean Sea. The proxy is mainly related to recent inputs from land-based litter sources. Despite the limitations of in-orbit technology, satellite detections are sufficient to map hot-spots and capture trends, providing an unprecedented source-to-sink view of the marine litter phenomenon. Torrential rains largely control marine litter inputs, while coastal boundary currents and wind-driven surface sweep arise as key drivers for its distribution over the ocean. Satellite-based monitoring proves to be a real game changer for marine litter research and management. Furthermore, the development of an ad-hoc sensor can lower the minimum detectable concentration by one order of magnitude, ensuring operational monitoring, at least for seasonal-to-interannual variability in the mesoscale.

Large-scale identification of rodenticide resistance in Rattus norvegicus and Mus musculus in the Netherlands based on Vkorc1 codon 139 mutations.

BACKGROUND: Resistance to rodenticides has been reported globally and poses a considerable problem for efficacy in pest control. The most-documented resistance to rodenticides in commensal rodents is associated with mutations in the Vkorc1 gene, in particular in codon 139. Resistance to anticoagulant rodenticides has been reported in the Netherlands since 1989. A study from 2013 showed that 25% of 169 Norway rats (Rattus norvegicus) had a mutation at codon 139 of the Vkorc1 gene. To gain insight in the current status of rodenticide resistance amongst R. norvegicus and house mice Mus musculus in the Netherlands, we tested these rodents for mutations in codon 139 of the Vkorc1 gene. In addition, we collected data from pest controllers on their use of rodenticides and experience with rodenticide resistance. RESULTS: A total of 1801 rodent samples were collected throughout the country consisting of 1404 R. norvegicus and 397 M. musculus. In total, 15% of R. norvegicus [95% confidence interval (CI): 13-17%] and 38% of M. musculus (95% CI: 33-43%) carried a genetic mutation at codon 139 of the Vkorc1 gene. CONCLUSION: This study demonstrates genetic mutations at codon 139 of the Vkorc1 gene in M. musculus in the Netherlands. Resistance to anticoagulant rodenticides is present in R. norvegicus and M. musculus in multiple regions in the Netherlands. The results of this comprehensive study provide a baseline and facilitate trend analyses of Vkorc1 codon 139 mutations and evaluation of integrated pest management (IPM) strategies as these are enrolled in the Netherlands. © 2022 The Dutch Pest and Wildlife. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Pelagic distribution of plastic debris (> 500 µm) and marine organisms in the upper layer of the North Atlantic Ocean.

At present, the distribution of plastic debris in the ocean water column remains largely unknown. Such information, however, is required to assess the exposure of marine organisms to plastic pollution as well as to calculate the ocean plastic mass balance. Here, we provide water column profiles (0-300 m water depth) of plastic (0.05-5 cm in size) concentration and key planktonic species from the eastern North Atlantic Ocean. The amount of plastic decreases rapidly in the upper few meters, from ~ 1 item/m3 (~ 1000 µg/m3) at the sea surface to values of ~ 0.001-0.01 items/m3 (~ 0.1-10 µg/m3) at 300 m depth. Ratios of plastic to plankton varied between ~ 10-5 and 1 plastic particles per individual with highest ratios typically found in the surface waters. We further observed that pelagic ratios were generally higher in the water column below the subtropical gyre compared to those in more coastal ecosystems. Lastly, we show plastic to (non-gelatinous) plankton ratios could be as high as ~ 102-107 plastic particles per individual when considering reported concentrations of small microplastics < 100 µm. Plastic pollution in our oceans may therefore soon exceed estimated safe concentrations for many pelagic species.

Concentration, anisotropic and apparent colour effects on optical reflectance properties of virgin and ocean-harvested plastics.

We present reflectance measurements collected from virgin and ocean-harvested plastics. Virgin plastics included high and low density polyethylene (HDPE, LDPE), polypropylene (PP) as well as polystyrene (PS). Ocean-harvested plastics were ropes, sheets, foam, pellets and fragmented items previously trawled from the North Pacific Garbage Patch. Nadir viewing angles and plastic pixel coverage were varied to advance our understanding of how reflectance shape and magnitude can be influenced by these parameters. We also investigated the effect of apparent colour of plastics on the measured reflectance from the ultraviolet (UV - 350 nm), visible, near to shortwave infrared (NIR, SWIR - 2500 nm). Statistical analyses indicated that the spectral reflectance of the plastics was significantly correlated to the percentage pixel coverage. There was no clear relationship between the reflectance observed and the viewing nadir angle but dampened materials seemed to be more isotropic (near-Lambertian) than their dry counterparts. A loss in reflectance was also determined between dry and wet plastics. Location of absorption features was not affected by the apparent colour of objects. In general, ocean-harvested plastics shared more identical absorption features (~960, 1215, 1440, 1732, 1920 nm) and had lower reflectance intensity compared to the virgin plastics (~980 nm). Prospects for satellite retrieval of plastic type and pixel plastic coverage are discussed based on Top-of-Atmosphere (TOA) signal simulated through radiative transfer computation using the documented plastic reflectances. Non-linear relationships between TOA reflectance and plastic coverage were observed depending on wavelength and plastic type. Most of the plastics analysed impact significantly the TOA signal but two plastic types did not produce strong signal at TOA (hard fragments, LDPE). Nevertheless, all plastic types produced detectable signals when observations were simulated within the sunglint direction. The measurements collected in this study are an extension to available high quality spectral reference libraries and can support further research in developing remote sensing algorithms for marine litter.

Cost-utility of repeated screening for Chlamydia trachomatis.

OBJECTIVE: To estimate the cost-effectiveness of repeated screening for chlamydia trachomatis at various time intervals compared to one-off screening of Dutch young adults. METHODS: We used a dynamic model to fully take the spread of the disease over time in the population into account, with data being used gathered within the context of a recently performed pilot study in The Netherlands. The screening frequencies analyzed were: every year, every 2 years, every 5 years, and every 10 years. The strategies were compared in terms of incremental cost-effectiveness, expressed as the net costs per quality-adjusted life-year (QALY). RESULTS: For all interval strategies, with the exception of screening every year, incremental cost-effectiveness stays below the informal Dutch threshold of euro20,000 per QALY. CONCLUSION: From a health-economic point of view, for the Dutch situation, we estimated screening every 2 years as the optimal strategy among the options investigated.

Cost effectiveness of itraconazole in the prophylaxis of invasive fungal infections.

BACKGROUND: Invasive fungal infections in neutropenic patients treated for haematological malignancies are associated with a high mortality rate and, therefore, require early treatment. As the diagnosis of invasive fungal infections is difficult, effective antifungal prophylaxis is desirable. So far, fluconazole has been the most commonly used. OBJECTIVE: To assess the cost effectiveness of itraconazole compared with both fluconazole and no prophylaxis for the prevention of invasive fungal infections in haematological patients, mean age 51 years, in Germany and The Netherlands. STUDY DESIGN: We designed a probabilistic decision model to fully incorporate the uncertainty associated with the risk estimates of acquiring an invasive fungal infection. These risk estimates were extracted from two meta-analyses, evaluating the effectiveness of fluconazole and itraconazole and no prophylaxis. The perspective of the analysis was that of the healthcare sector; only medical costs were taken into account. All costs were reported in euro, year 2004 values.Cost effectiveness was expressed as net costs per invasive fungal infection averted. No discounting was performed, as the model followed patients during their neutropenic period, which was assumed to be less than 1 year. RESULTS: According to our probabilistic decision model, the monetary benefits of averted healthcare exceed the costs of itraconazole prophylaxis under baseline assumptions (95% CI: from cost-saving to euro 5000 per invasive fungal infection averted). Compared with fluconazole, itraconazole is estimated to be both more effective and more economically favourable, with a probability of almost 98%. CONCLUSIONS: In specific groups of neutropenic patients treated for haematological malignancies, itraconazole prophylaxis could potentially reduce overall healthcare expenditure, without harming effectiveness, in settings where fluconazole is common practice in the prophylaxis of invasive fungal infections.

Cost-effectiveness of screening for albuminuria with subsequent fosinopril treatment to prevent cardiovascular events: A pharmacoeconomic analysis linked to the prevention of renal and vascular endstage disease (PREVEND) study and the prevention of renal and vascular endstage disease intervention trial (PREVEND IT).

OBJECTIVE: This study estimated the cost-effectiveness,from the Dutch health care perspective, of screening for albuminuria in the general Dutch population to prevent cardiovascular events (CVEs) with subsequent angiotensin-converting enzyme inhibitor treatment, using data from the Prevention of REnal and Vascular ENdstage Disease Intervention Trial (PREVEND IT). METHODS: PREVEND IT was a single-center, double-blind, randomized, placebo-controlled trial with a 2 x 2 factorial design within the larger observational Prevention of REnal and Vascular ENdstage Disease (PREVEND) study. The PREVEND IT study was conducted to assess the effects of fosinopril 20 mg and pravastatin 40 mg on CVEs in subjects with specific inclusion criteria: urinary albumin excretion (UAE) rate in the range from 15 to 300 mg/d, blood pressure <160/100 mm Hg, and plasma cholesterol level <8.0 mmol/L. Cost-effectiveness estimates for the Dutch population were expressed in euros (2002; 1 euro = US 1.01 dollars) as net costs per life-year gained (LYG) in the baseline and sensitivity (stochastic) analyses. RESULTS: Data were assessed for 864 subjects, with a mean (SD) follow-up of 46 (7) months. CVEs occurred in 45 (5.2%) subjects. Subjects who received fosinopril had a 40% lower incidence of CVEs than subjects in the placebo group (3.9% vs 6.5%, respectively; P = NS). The cost-effectiveness of screening for albumnuria was determined to be euro 16,700/LYG for the study population. Stochastic analysis indicated that the probability of the cost-effectiveness being below the suggested Dutch threshold of euro 20,000/LYG was 59% in the baseline analysis. The probability of cost-effectiveness below euro 20,000/LYG would increase to 91% if only subjects with UAE >50 mg/d were treated with fosinopril. Limiting the screening to subjects aged >50 years and >60 years also improved cost-effectiveness. CONCLUSIONS: The results of our study suggest that screening the general Dutch population for albuminuria and subsequently treating those found positive with fosinopril may be cost-effective compared with no screening and adopting the Dutch health care perspective. However, confirmation from larger multicenter trials is needed.

Cost-effectiveness of obinutuzumab for chronic lymphocytic leukaemia in The Netherlands.

BACKGROUND: Obinutuzumab combined with chlorambucil (GClb) has shown to be superior to rituximab combined with chlorambucil (RClb) and chlorambucil (Clb) in newly diagnosed patients with chronic lymphocytic leukaemia (CLL). This study evaluates the cost-effectiveness per life-year and quality-adjusted life-year (QALY) of GClb compared to RClb, Clb, and ofatumumab plus chlorambucil (OClb) in The Netherlands. METHODS: A Markov model was developed to assess the cost-effectiveness of GClb, RClb, Clb and other treatments in the United Kingdom. A country adaptation was made to estimate the cost-effectiveness of these therapies in The Netherlands using Dutch unit costs and Dutch data sources for background mortality and post-progression survival. RESULTS: An incremental gain of 1.06 and 0.64 QALYs was estimated for GClb compared to Clb and RClb respectively, at additional costs of €23,208 and €7254 per patient. Corresponding incremental cost-effectiveness ratios (ICERs) were €21,823 and €11,344 per QALY. Indirect treatment comparisons showed an incremental gain varying from 0.44 to 0.77 QALYs for GClb compared to OClb and additional costs varying from €7041 to €5028 per patient. The ICER varied from €6556 to €16,180 per QALY. Sensitivity analyses showed the robustness of the results. CONCLUSION: GClb appeared to be a cost-effective treatment strategy compared to RClb, OClb and Clb.

Economic evaluation of a randomized trial comparing Helicobacter pylori test-and-treat and prompt endoscopy strategies for managing dyspepsia in a primary-care setting.

BACKGROUND: In western European countries, most dyspeptic patients are initially managed by their general practitioners (GPs), who use a range of strategies to manage dyspepsia. We performed an economic analysis of a Helicobacter pylori test-and-treat strategy versus a prompt endoscopy approach in a primary care setting. METHODS: Data were used from the Strategy: Endoscopy versus Serology (SENSE) study, performed in The Netherlands from 1998 to 2001. Patients were randomized to a prompt endoscopy (n = 105) or test-and-treat (n = 118) group. Follow-up lasted 1 year. Adverse events were not recorded in the SENSE study. Health care costs were based on the total amount of dyspepsia-related drugs used, the number of dyspepsia-related GP visits, the number of diagnostic tests, and the number of dyspepsia-related referrals to specialists. The use of medical resources was calculated as standardized costs for 1999, recorded as euros. (On December 31, 1999, 1.00 Euro = 1.00 US dollar.) Quality of life was measured at inclusion and 1 year later, using the RAND-36 questionnaire. To calculate quality-adjusted life-years (QALYs), we transformed the individual scores of the RAND-36 into 1 overall score, the Health Utilities Index Mark 2, which introduced a limitation to the study. An incremental cost-effectiveness ratio (ICER) was calculated. The 95% confidence limits were calculated using a parametric bootstrap method with angular transformation. All cost data were analyzed from a third-party payer perspective. RESULTS: The total costs per patient were 511 Euros, with 0.037 QALY gained per patient, in the test-and-treat group, and 748 Euros, with 0.032 QALY gained per patient, in the endoscopy group (between groups, P < 0.001 and P = NS, respectively). The point estimate of the ICER indicated that the test-and-treat strategy yielded cost savings and QALYs gained. Parametric bootstrap confidence limits indicated cost savings per QALY gained in 75.7% of the bootstrap simulations. CONCLUSION: This analysis of data from the SENSE1026 study suggests that the H pylori test-and-treat strategy was more cost-effective than prompt endoscopy in the initial management of dyspepsia in general practice, from the perspective of a third-party payer.

Cost effectiveness of vaccination against pandemic influenza in European countries: mathematical modelling analysis.

OBJECTIVE: To investigate whether a single optimal vaccination strategy exists across countries to deal with a future influenza pandemic by comparing the cost effectiveness of different strategies in various pandemic scenarios for three European countries. DESIGN: Economic and epidemic modelling study. SETTINGS: General populations in Germany, the Netherlands, and the United Kingdom. DATA SOURCES: Country specific patterns of social contact and demographic data. MODEL: An age structured susceptible-exposed-infected-recovered transmission model that describes how an influenza A virus will spread in the populations of Germany, the Netherlands, and the United Kingdom. INTERVENTIONS: Comparison of four vaccination strategies: no vaccination, blanket vaccination, vaccination of elderly people (≥ 65 years), and vaccination of high transmitters (5-19 years). The four strategies were evaluated for scenarios in which a vaccine became available early or at the peak of the pandemic, and in which either everyone was initially susceptible or older age groups had pre-existing immunity. MAIN OUTCOME MEASURE: Cost per quality adjusted life years (QALYs) gained. RESULTS: All vaccination strategies were cost effective (incremental cost per QALY gained, comparing intervention with non-intervention). In scenarios where the vaccine became available at the peak of the pandemic and there was pre-existing immunity among elderly people the incremental cost effectiveness ratios for vaccinating high transmitters were €7325 (£5815; $10,470) per QALY gained for Germany, €10,216 per QALY gained for the Netherlands, and €7280 per QALY gained for the United Kingdom. The most cost effective strategy not only differed across the pandemic scenarios but also between countries. Specifically, when the vaccine was available early in the pandemic and there was no pre-existing immunity, in Germany it would be most cost effective to vaccinate elderly people ( €940 per QALY gained), whereas it would be most cost effective to vaccinate high transmitters in both the Netherlands (€525 per QALY gained) and the United Kingdom (€163 per QALY gained). This difference in optimal strategies was due to differences in the demographic characteristics of the countries: Germany has a significantly higher proportion of elderly people compared with the Netherlands and the United Kingdom. CONCLUSIONS: No single vaccination strategy was most cost effective across countries. With aging populations, pre-existing immunity in particular could be of crucial importance for the cost effectiveness of options to mitigate a future influenza pandemic.

Cost-Effectiveness Analysis of Hepatitis B Immunization in Vietnam: Application of Cost-Effectiveness Affordability Curves in Health Care Decision Making.

OBJECTIVES: To perform a cost-effectiveness analysis and to identify the cost-effectiveness affordability levels for a newborn universal vaccination program against hepatitis B virus (HBV) in Vietnam. METHODS: By using a Markov model, we simulated a Vietnamese birth cohort using 1,639,000 newborns in 2002 and estimated the incremental cost-effectiveness ratios for quality-adjusted life-year gained following universal newborn HBV vaccination. Two types of analyses were performed, including and excluding expenditures on the treatment of chronic hepatitis B and its complications. We used Monte Carlo simulations to examine cost-effectiveness acceptability and affordability from the payer's perspective and constructed a cost-effectiveness affordability curve to assess the costs and health effects of the program. RESULTS: In the base-case analysis, newborn universal HBV vaccination reduced the carrier rate by 58% at a cost of US $42 per carrier averted. From the payer's perspective, incremental cost-effectiveness ratio per quality-adjusted life-year gained was US $3.77, much lower than the 2002 per-capita gross domestic product of US $440. Vaccination could potentially be affordable starting at a US $2.1 million budget. At the cost-effectiveness threshold of US $3.77 per quality-adjusted life-year and an annual budget of US $5.9 million, the probability that vaccination will be both cost-effective and affordable was 21%. CONCLUSIONS: Universal newborn HBV vaccination is highly cost-effective in Vietnam. In low-income, high-endemic countries, where funds are limited and the economic results are uncertain, our findings on the cost-effectiveness affordability options may assist decision makers in proper health investments.

Cost benefit and cost effectiveness of antifungal prophylaxis in immunocompromised patients treated for haematological malignancies: reviewing the available evidence.

There has been a large increase in the incidence of invasive fungal infections (IFIs) over the past decades, largely because of the increasing size of the population at risk. One of the major risk groups for IFIs are patients with haematological malignancies treated with cytotoxic chemotherapy or undergoing haematopoietic stem cell transplantation. These IFIs are associated with high morbidity and mortality rates. Consequently, as the diagnosis of IFIs is difficult, antifungal prophylaxis is desirable in high-risk patients. Furthermore, as the economic impact of IFIs is also significant, it is important to assess the cost benefit and cost effectiveness of each prophylactic agent in order to aid decisions concerning which prophylactic agent provides the best value for limited healthcare resources. This article systematically reviews the available pharmacoeconomic evidence regarding antifungal prophylaxis in immunocompromised patients treated for haematological malignancies. Furthermore, specific points of interest concerning economic analyses of antifungal prophylaxis are briefly discussed. Considering the available evidence, antifungal prophylaxis in immunocompromised patients treated for haematological malignancies seems to be an intervention with favourable cost-benefit, cost-effectiveness and cost-saving potential. Furthermore, recently introduced antifungal agents seem to be attractive alternatives to fluconazole from a pharmacoeconomic point of view. However, due to wide heterogeneity in patient characteristics, underlying diseases, hospital settings and study methods in the included economic studies, as well as the lack of 'head-to-head' trials, it is difficult to find clear evidence of the economic advantages of a single prophylactic agent. Furthermore, we show that the results of cost-effectiveness analyses are highly dependent on several crucial factors that influence the baseline IFI incidence rates and, therefore, differ per patient population or region.

Cost-effectiveness analysis of various pertussis vaccination strategies primarily aimed at protecting infants in the Netherlands.

BACKGROUND: Pertussis is a highly contagious respiratory disease. Despite a high rate of vaccine coverage through the Dutch national immunization program, the incidence of pertussis remains high in the Netherlands and the risk of infection continues. Because pertussis is most severe in unimmunized infants and infants who have only received some of the recommended doses, new pertussis immunization strategies should be considered to protect this vulnerable population. OBJECTIVE: This study was designed to estimate the cost-effectiveness of 3 new immunization strategies for possible addition to the current Dutch national immunization program: immunization of the infant at birth, immunization of the parents immediately after birth of the child (cocooning), and maternal immunization during the third trimester of pregnancy. METHODS: A literature search was performed in the PubMed database for articles published in English, German, and Dutch using the following terms: pertussis, whooping cough, vaccination strategies, maternal immunization, cocooning, at birth, vaccine efficacy, mortality, underreporting, prevalence, incidence, and cost-effectiveness. A decision-tree model was developed for this analysis, and data on pertussis morbidity and costs were collected consistently for different age groups (infants <1 year of age and adults 25 to 34 years of age). The size of the infant cohort was set at 200,000 to approximate previous Dutch birth cohorts. The size of the adult cohort was set at 401,380 parents for the cocooning strategy and 201,380 mothers for the maternal immunization strategy. Health benefits (quality-adjusted life-years [QALYs]) and costs were estimated in both cohorts for each of the 3 immunization strate- gies. Incremental cost-effectiveness ratios were calculated from both a payer's and a societal perspective. The robustness of the results was determined through sensitivity analysis. RESULTS: In the base-case analysis, cocooning and maternal immunization were found to be effective in reducing the incidence of pertussis among infants (123 and 174 infant cases were expected to be prevented, respectively). Furthermore, cocooning and maternal immunization were estimated to be cost-effective from a payer's perspective (euro4600 [US $6400]/QALY and euro3500 [$4900]/QALY, respectively) and even cost-saving from a societal perspective (savings of up to euro7200 [$10,100] and euro5000 [$7000], respectively). Sensitivity analyses revealed that favorable cost-effectiveness was generally robust. In the sensitivity analysis, the cost-effectiveness of cocooning and maternal immunization was mostly sensitive for changes in assumptions on underreporting (200-fold increase in reported number of symptomatic cases) of pertussis disease and infection. With no underreporting, the ICER was estimated at euro211,900 ($296,700)/QALY for cocooning and euro81,600 ($114,200)/QALY for maternal immunization from a payer's perspective. However, even at much lower levels of underreporting (20- to 30-fold increase in incidence), cost-effectiveness remained favorable. The cost-effectiveness of the third strategy, at-birth immunization, was highly unfavorable (euro329,900 [$461,900]/QALY from a payer's perspective and euro330,100 [$462,100]/ QALY from a societal perspective). CONCLUSIONS: This study estimated that the addition of cocooning or maternal immunization to the current Dutch national immunization program likely would be cost-effective or even cost-saving. These estimates were mainly due to reduction in the number of cases among parents, which are likely to be mild and therefore would largely remain unreported. Immunization at birth was not a cost-effective strategy. Cocooning was the most expensive intervention to implement; however, it resulted in the highest number of QALYs gained (mainly in adults). Maternal immunization would offer better protection of infants, due to maternally acquired antibodies.

Cost-effectiveness of adolescent pertussis vaccination for the Netherlands: using an individual-based dynamic model.

BACKGROUND: Despite widespread immunization programs, a clear increase in pertussis incidence is apparent in many developed countries during the last decades. Consequently, additional immunization strategies are considered to reduce the burden of disease. The aim of this study is to design an individual-based stochastic dynamic framework to model pertussis transmission in the population in order to predict the epidemiologic and economic consequences of the implementation of universal booster vaccination programs. Using this framework, we estimate the cost-effectiveness of universal adolescent pertussis booster vaccination at the age of 12 years in the Netherlands. METHODS/PRINCIPAL FINDINGS: We designed a discrete event simulation (DES) model to predict the epidemiological and economic consequences of implementing universal adolescent booster vaccination. We used national age-specific notification data over the period 1996-2000--corrected for underreporting--to calibrate the model assuming a steady state situation. Subsequently, booster vaccination was introduced. Input parameters of the model were derived from literature, national data sources (e.g. costing data, incidence and hospitalization data) and expert opinions. As there is no consensus on the duration of immunity acquired by natural infection, we considered two scenarios for this duration of protection (i.e. 8 and 15 years). In both scenarios, total pertussis incidence decreased as a result of adolescent vaccination. From a societal perspective, the cost-effectiveness was estimated at €4418/QALY (range: 3205-6364 € per QALY) and €6371/QALY (range: 4139-9549 € per QALY) for the 8- and 15-year protection scenarios, respectively. Sensitivity analyses revealed that the outcomes are most sensitive to the quality of life weights used for pertussis disease. CONCLUSIONS/SIGNIFICANCE: To our knowledge we designed the first individual-based dynamic framework to model pertussis transmission in the population. This study indicates that adolescent pertussis vaccination is likely to be a cost-effective intervention for The Netherlands. The model is suited to investigate further pertussis booster vaccination strategies.

Conclusions on (cost-)effectiveness of pertussis booster vaccination strategies highly dependent on selections made in evidence review.

This letter reacts on a paper recently published in this journal, reviewing the effectiveness and (cost-)effectiveness of pertussis booster vaccination strategies. We argue that a different selection of (cost-)effectiveness data could validly be made than the one presented in the review as being considered most robust. In particular, we explicitly present an alternative set of (cost-)effectiveness data.

Cost-effectiveness of a potential future Helicobacter pylori vaccine in the Netherlands: the impact of varying the discount rate for health.

To estimate the cost-effectiveness of a potential Helicobacter pylori (HP) vaccine for the Dutch situation, we developed a Markov model. Several HP prevalence scenarios were assessed. Additionally, we assessed the impact of the discount rate for health on the outcomes, as this influence can be profound for vaccines. When applying the current discount rate of 1.5% for health, the expected cost-effectiveness of HP vaccination is estimated below the informal Dutch threshold of euro 20,000/LYG when the HP prevalence is assumed > or =20% in the Dutch population. In conclusion, we showed that HP vaccination could possibly be a cost-effective intervention. However, this depends to a large extend on the prevalence of HP in the population. Furthermore, we showed the large impact of the discount rate for health on the cost-effectiveness of a HP vaccination program, illustrative for other vaccination programs.

Vancomycin vs teicoplanin in the treatment of Gram-positive infections: a pharmacoeconomic analysis in a Turkish University Hospital.

OBJECTIVE: The aim of this study was to estimate and compare the costs of vancomycin and teicoplanin in the treatment of Gram-positive hospital infections in Turkey using a cost minimisation analysis. SETTING: Hacettepe University Hospital, Ankara, Turkey. METHOD: The health-care provider's perspective was considered within formal pharmacoeconomic assessment methodology. The records of 76 patients who had been hospitalised and treated for Gram-positive infections at Hacettepe University Hospital between 16 July 2003 and 22 November 2003 were retrospectively evaluated to obtain individual data on resources and associated costs. MAIN OUTCOME MEASURE: From a cost minimisation perspective, hospital directors may consider teicoplanin to be a relevant option in addition to vancomycin. RESULT: The estimated mean treatment cost per patient was 1,780 TRY (1,101 EUR) for teicoplanin and 1,429 TRY (884 EUR) for vancomycin, with statistical analysis failing to reveal any significant difference between the two drugs in terms of these total costs (p = 0.33). This cost minimisation analysis shows that the average costs of vancomycin and teicoplanin per patient observed did not differ significantly. CONCLUSION: Other potential advantages of one drug over the other, as reported by other authors, such as differing safety profiles or advantages in administration, may ultimately decide which is preferred.

Systematic screening for Chlamydia trachomatis: estimating cost-effectiveness using dynamic modeling and Dutch data.

OBJECTIVE: To estimate the cost-effectiveness of a systematic one-off Chlamydia trachomatis (CT) screening program including partner treatment for Dutch young adults. METHODS: Data on infection prevalence, participation rates, and sexual behavior were obtained from a large pilot study conducted in The Netherlands. Opposite to almost all previous economic evaluations of CT screening, we developed a dynamic Susceptible-Infected-Susceptible (SIS) model to estimate the impact of the screening program on the incidence and prevalence of CT in the population. SIS models are widely used in epidemiology of infectious diseases, for modeling the transmission dynamics over time. Subsequently, a predictive decision model was used to calculate the complications averted by the screening program. Cost-effectiveness was expressed as the net costs per major outcome averted (MOA) and was estimated in the baseline analysis and in sensitivity analysis. RESULTS: The overall prevalence decreased from 1.79% to 1.05% as a result of the screening program directed at both men and women. The program costs were mainly offset by the averted costs, although not fully. Resulting net costs per MOA were 373 euro sin the baseline analysis. Sensitivity analysis showed that partner treatment and sending a reminder are important aspects improving cost-effectiveness. Additionally, restricting the screening to women only was estimated to save costs. CONCLUSIONS: Our cost-effectiveness analysis shows that the Dutch society has net to pay for the prevention of CT-complications through screening young men and women. One could argue although that 373 euros per MOA presents a reasonable cost. A screening program consisting of screening women only should always be adopted from a pharmacoeconomic point of view. Our dynamic approach appreciates better the specific characteristics of an infectious disease, such as CT.

How to estimate the population that is covered by community pharmacies? An evaluation of two methods using drug utilisation information.

PURPOSE: Pharmacy-dispensing data are valuable sources of drug information, but the population that is covered by the pharmacies is often difficult to determine. We evaluated two methods using drug utilisation information to estimate the population size: a drug-use-based extrapolation of a known part of the population and a capture-recapture estimation without any prior knowledge of the population. METHODS: Using pharmacy-dispensing data of three towns with known populations in the Netherlands, we estimated age-and-sex specific population sizes by extrapolating the proportion of drug-using inhabitants. In addition, we applied two-source and three-source capture-recapture models with all combinations of the following drug groups as different sources: anti-asthmatics, analgesics, antibiotics and anti-histamines. RESULTS: Drug-use-based extrapolation resulted in the best estimates with the least variability. All capture-recapture models provided underestimations of the true population. Three-source capture-recapture resulted in better average estimates than two-source capture-recapture, but also had more variability. CONCLUSIONS: If a part of the population is known, and if there is reason to assume that drug utilisation patterns do not vary within the region, it is best to use drug-use-based extrapolation. In all other situations capture-recapture may be considered, with as main limitation that we found all models to underestimate the population considerably.