On Endogenous Growth: The Implications of Environmental Externalities

This paper uses an endogenous growth model to examine the interaction between trade, economic growth, and the environment. We find that whether trade enhances or retards growth depends on the relation between factor intensities of exportable, importable, and R&D and the relative abundance of the factor R&D uses more intensively. Depending on the intertemporal elasticity of substitution, the long-run rate of economic growth changes with environmental externalities. Concerns about the environment can explain a significant part of cross-country difference in growth rates. For the empirically reported range of the elasticity of intertemporal substitution, countries which care more about the environment grow faster. The effects of trade on the environment and welfare depend on the elasticities of supply for the two traded goods, the terms of trade effect on growth, and pollution intensities. The decentralized and Pareto optimal growth rates are, in general, different. The market growth rate is bigger than the optimal rate the larger the degree of monopoly power in the innovation sector and the stronger the effects of environmental externalities. The policy implications of this divergence are discussed. We also consider numerical exercises to broaden the insights from the analytical results and allow for incorporating pollution abatementEnvironmental Economics and Policy, F11, O31, O41, Q20,

Environment in Three Classes of Endogenous Growth Models

The implications of environmental externalities are studied within three classes of endogenous growth models viz. the linear technology models, the human capital models, and the R&D and innovation models. The long-run rate of economic growth changes when environmental extemalities are introduced; the direction of change depends on the severity of extemalities and the intertemporal elasticity of substitution. The presence of environmental externalities cause the decentralized growth rate to diverge from the efficient rate. Which rate is bigger than the other depends, among other things, on the valuation of consumption relative to environmental quality. Several policy changes to align the two paths are discussed. The models are calibrated to U.S. data.Environmental Economics and Policy, International Development,

A Dynamic CGE Model: An Application of R&D- Based Endogenous Growth Model Theory

An R&D based endogenous growth - applied general equilibrium model is developed from an underlying analytical model which combines Romer's capital variety with Grossman and Helpman's multi-sector open economy model. The transitional dynamics of the analytical model are derived. For numerical implementation, a time discrete empirical model, with an Armington structure, is fit to East Asian data of the social accounting matrix variety. Simulations of trade reform are performed and their static and dynamic effects compared. The transition paths of the state variables are found to have a half-life of five to six periods. A solution of the Social Planner's problem, and interventions which seek to obtain this outcome from the decentralized model are also obtained'.Applied General Equilibrium, Trade, Growth, International Relations/Trade, F11, 031, 041,

Epidemiologic natural history and clinical management of Human Papillomavirus (HPV) Disease: a critical and systematic review of the literature in the development of an HPV dynamic transmission model

<p>Abstract</p> <p>Background</p> <p>Natural history models of human papillomavirus (HPV) infection and disease have been used in a number of policy evaluations of technologies to prevent and screen for HPV disease (e.g., cervical cancer, anogenital warts), sometimes with wide variation in values for epidemiologic and clinical inputs. The objectives of this study are to: (1) Provide an updated critical and systematic review of the evidence base to support epidemiologic and clinical modeling of key HPV disease-related parameters in the context of an HPV multi-type disease transmission model which we have applied within a U.S. population context; (2) Identify areas where additional studies are particularly needed.</p> <p>Methods</p> <p>Consistent with our and other prior HPV natural history models, the literature review was confined to cervical disease and genital warts. Between October 2005 and January 2006, data were gathered from the published English language medical literature through a search of the PubMed database and references were examined from prior HPV natural history models and review papers. Study design and data quality from individual studies were compared and analyses meeting pre-defined criteria were selected.</p> <p>Results</p> <p>Published data meeting review eligibility criteria were most plentiful for natural history parameters relating to the progression and regression of cervical intraepithelial neoplasia (CIN) without HPV typing, and data concerning the natural history of HPV disease due to specific HPV types were often lacking. Epidemiologic evidence to support age-dependency in the risk of progression and regression of HPV disease was found to be weak, and an alternative hypothesis concerning the time-dependence of transition rates is explored. No data were found on the duration of immunity following HPV infection. In the area of clinical management, data were observed to be lacking on the proportion of clinically manifest anogenital warts that are treated and the proportion of cervical cancer cases that become symptomatic by stage.</p> <p>Conclusion</p> <p>Knowledge of the natural history of HPV disease has been considerably enhanced over the past two decades, through the publication of an increasing number of relevant studies. However, considerable opportunity remains for advancing our understanding of HPV natural history and the quality of associated models, particularly with respect to examining HPV age- and type-specific outcomes, and acquired immunity following infection.</p

A primer on using mathematics to understand COVID-19 dynamics : modeling, analysis and simulations

The novel coronavirus (COVID-19) pandemic that emerged from Wuhan city in December 2019 overwhelmed health systems and paralyzed economies around the world. It became the most important public health challenge facing mankind since the 1918 Spanish flu pandemic. Various theoretical and empirical approaches have been designed and used to gain insight into the transmission dynamics and control of the pandemic. This study presents a primer for formulating, analysing and simulating mathematical models for understanding the dynamics of COVID-19. Specifically, we introduce simple compartmental, Kermack-McKendrick-type epidemic models with homogeneously- and heterogeneously-mixed populations, an endemic model for assessing the potential population-level impact of a hypothetical COVID-19 vaccine. We illustrate how some basic non-pharmaceutical interventions against COVID-19 can be incorporated into the epidemic model. A brief overview of other kinds of models that have been used to study the dynamics of COVID-19, such as agent-based, network and statistical models, is also presented. Possible extensions of the basic model, as well as open challenges associated with the formulation and theoretical analysis of models for COVID-19 dynamics, are suggested.The Simons Foundation and the National Science Foundation.http://www.keaipublishing.com/idmam2022Mathematics and Applied Mathematic

Model for Assessing Human Papillomavirus Vaccination Strategies

A prophylactic quadrivalent vaccine can cost-effectively reduce the incidence of cervical cancer, cervical intraepithelial neoplasia, and genital warts

Public Health Impact and Cost-Effectiveness of Hepatitis A Vaccination in the United States: A Disease Transmission Dynamic Modeling Approach

Objective: To assess the population-level impact and costeffectiveness of hepatitis A vaccination programs in the United States. Methods: We developed an age-structured population model of hepatitis A transmission dynamics to evaluate two policies of administering a twodose hepatitis A vaccine to children aged 12 to 18 months: 1) universal routine vaccination as recommended by the Advisory Committee on Immunization Practices in 2006 and 2) Advisory Committee on Immunization Practices&apos;s previous regional policy of routine vaccination of children living in states with high hepatitis A incidence. Inputs were obtained from the published literature, public sources, and clinical trial data. The model was fitted to hepatitis A seroprevalence (National Health and Nutrition Examination Survey II and III) and reported incidence from the National Notifiable Diseases Surveillance System (1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995). We used a societal perspective and projected costs (in 2013 US $), qualityadjusted life-years, incremental cost-effectiveness ratio, and other outcomes over the period 2006 to 2106. Results: On average, universal routine hepatitis A vaccination prevented 259,776 additional infections, 167,094 outpatient visits, 4781 hospitalizations, and 228 deaths annually. Compared with the regional vaccination policy, universal routine hepatitis A vaccination was cost saving. In scenario analysis, universal vaccination prevented 94,957 infections, 46,179 outpatient visits, 1286 hospitalizations, and 15 deaths annually and had an incremental cost-effectiveness ratio of$21,223/quality-adjusted life-year when herd protection was ignored. Conclusions: Our model predicted that universal childhood hepatitis A vaccination led to significant reductions in hepatitis A mortality and morbidity. Consequently, universal vaccination was cost saving compared with a regional vaccination policy. Herd protection effects of hepatitis A vaccination programs had a significant impact on hepatitis A mortality, morbidity, and cost-effectiveness ratios

Оценка экономической эффективности применения ралтегравира у пациентов без опыта терапии ВИЧ-инфекции типа 1 в России

The purpose of the work performed was assessment of cost efficiency of Raltegravir within the schemes of antiretroviral therapy as compared to the schemes on the basis of drugs from the group of protease inhibitors with adult patients with Type 1 HIV infection (HIV-1) that have no experience of treatment.Materials and methods. In the Markov's model developed for assessment of long-term clinical and economic indicators of efficiency of Raltegravir with adult patients with HIV-1 that have no experience of antiretroviral therapy, pharmacoeconomic analysis of "costs and benefits" was performed in accordance with recommendations of the Panel on Cost-effectiveness in Health and Medicine and with consideration of requirements of specialized Russian manuals. Direct costs for application of the schemes compared were calculated on the basis of applicable norms of financing of the Russian Federation. Consumptions of health care resources and life standard indicators were determined on the basis of foreign studies regarding each of the 18 states of health provided with Markov's model and distinguished according to the number of CD4 cells and viral load.Study results. It was demonstrated that Raltegravir within schemes of antiretroviral therapy of the first line, as compared to the schemes on the basis of drugs from the group of protease inhibitors with subsequent second line therapy on the basis of non-nucleoside reverse transcriptase inhibitors (including Raltegravir in addition to the optimized treatment at the last stage), was a more cost efficient alternative as it had clinical benefits with affordable additional expenses. The increment cost efficiency rate (ICER) per a year of saved life with consideration of its quality comprised 1,097,078 rubles without exceeding the threshold of readiness to pay for a year of quality life equal to 3 GDP per capita.Целью проведенной работы была оценка затратной эффективности ралтегравира в составе схем антиретровирусной терапии по сравнению со схемами на основе препаратов из группы ингибиторов протеазы у взрослых пациентов с ВИЧ-инфекцией типа 1 (ВИЧ-1), не имеющих опыта лечения.Материалы и методы. В модели Маркова, разработанной для оценки долгосрочных клинических и экономических показателей эффективности ралтегравира у взрослых пациентов с ВИЧ-1, не имеющих опыта антиретровирусной терапии, был проведен фармакоэкономический анализ «затраты-полезность» в соответствии с рекомендациями Рабочей группы по оценке затратной эффективности в сфере здравоохранения и медицины (Panel on Cost-effectiveness in Health and Medicine) и с учетом требований российских специализированных руководств. На основании действующих нормативов финансирования РФ рассчитаны прямые затраты на применение сравниваемых схем. Потребление ресурсов здравоохранения и показатели качества жизни определялись на основании зарубежных исследований для каждого из 18 предусмотренных моделью Маркова состояний здоровья, выделенных по числу CD4 клеток и вирусной нагрузки.Результаты исследования. Показано, что ралтегравир в составе схем антиретровирусной терапии первой линии по сравнению со схемами на основе ингибиторов протеазы с последующей терапией препаратами второй линии на основе ненуклеозидных ингибиторов обратной транскриптазы (включая ралтегравир в дополнение к оптимизированной терапии на последнем этапе) является более затратно-эффективной альтернативой, так как обладает клиническими преимуществами при приемлемых дополнительных затратах. Инкрементный показатель приращения эффективности затрат (ICER) на год сохраненной жизни с учетом ее качества составил 1 097 078 руб., не превышая порог готовности платить за год качественной жизни, равного 3 ВВП на душу населения

Progression and regression of incident cervical HPV 6, 11, 16 and 18 infections in young women

<p>Abstract</p> <p>Background</p> <p>We describe type-specific progression, regression and persistence of incident human papillomavirus (HPV)-6-11-16 and -18 infections, along with type distribution in cervical intra-epithelial neoplasia (CIN) lesions.</p> <p>Methods</p> <p>The study population consisted of 16–23 year-old women undergoing Pap testing and cervical swab polymerase chain reaction testing for HPV DNA at approximate 6 month intervals for up to 4 years in the placebo arm of a clinical trial of an HPV 16-vaccine. HPV types in incident infections were correlated with types in lesion biopsy specimens.</p> <p>Results</p> <p>56.7% of CIN-1 and nearly one-third of CIN-2/3 lesions following incident HPV-6-11-16 or -18 infections did not correlate with the incident infection HPV type. Cumulative 36-month progression rates to CIN-2/3 testing positive for the relevant HPV type were highest for HPV-16 infections (16.5%), followed by HPV-18 (8.2%). Overall, 26.0% of CIN-1, 50.0% of CIN-2 and 70.6% of CIN-3 biopsies tested positive for HPV-6-11-16-18 infections.</p> <p>Conclusion</p> <p>Women with a given HPV type may often be co-infected or subsequently infected with other types which may lead to subsequent cervical lesions. This issue has been addressed in this study reporting data for the natural history of HPV-6-11-16 and -18 infections and is a relevant consideration in designing future studies to evaluate the incidence/risk of CIN following other type-specific HPV infections.</p