Epi-SCIENCE

Impact of dengue vaccination choice on Zika risk: free riders and the tragedy of the commons

Christopher Kribs — Wed, 28 Jun 2023 00:00:00 -0600

Dengue vaccination, long in development, has become controversial as it may cause antibody-dependent enhancement (ADE) in dengue-seronegatives. Under partial vaccine failure, ADE increases case severity and may also affect Zika infections since the two viruses are closely related.
From an individual perspective, the vaccination of others appears beneficial, but becoming vaccinated oneself may increase the risk of ADE and thus serious illness, for both diseases. From a population-level perspective, vaccination is expected to reduce the spread of dengue but increase Zika incidence. Nevertheless, prior mathematical modeling research has shown that in some cases, a small number of dengue vaccinations may reduce the final size of a Zika outbreak despite increasing its ability to spread. This study reconciles these results and then evaluates individual risks to both the vaccinated and the unvaccinated in order to connect to broader themes in complex vaccination decisions, such as free riders and the tragedy of the commons. A substantial new finding is that a dual outbreak may change which vaccination decision minimizes risk, compared to single-outbreak scenarios.

Consequences of Traceable Mobility in Populations Exhibiting Strong Allee Effect

Baltazar Espinoza, Yun Kang, Oyita Udiani — Wed, 28 Jun 2023 00:00:00 -0600

In this research, we study the impacts of the traceable mobility in a two-patch environment when the population in each patch exhibits strong Allee effects. Traveling individuals are traced across patches by budgeting the average time spent in each patch while keeping their place of residency. Particularly, we focus on the impact that the effective population (residents and visitors) produces on regional dynamics.

Our results show that low mobility across regions produces simple dynamics, where orbits converge to single or double extinction, or to a coexistence steady state. We derive mobility conditions under which an endangered population may benefit of the presence of a visitant one and avoid extinction -- the rescue effect. Nonetheless, increments in the visiting population would also lead the resident population to extinction -- the induced extinction effect.

Sufrimiento psíquico y salud pública.

Melissa Molina, Adriana Sánchez, Jorge Luis Núñez — Wed, 28 Jun 2023 00:00:00 -0600

In this paper, we make the discussion about the approach to mental suffering presented by patients who are treated at the Day Center for Mental Health. The brief is based on a project called ``Specialized Community Care Device of the Dr. Roberto Chacón Paut Hospital'', which was presented to the Medical Management of the Caja Costarricense del Seguro Social (CCSS) in 2021. This was developed by two psychiatrists in conjunction with a number of specialists from the institution. In its management, had have participated psychiatry, nursing, psychology, nutrition, social work, and occupational therapy professionals. To understand the emergence of this initiative in the current context, it is necessary to conduct an epistemological, ontological, and ethical discussion regarding public health policies and practices for clinical care, in Costa Rica and other parts of the world, as well as a debate on different approaches, such as interventional biomedical, antipsychiatry, community psychiatry and psychoanalysis. In this case, an integral vision is defended about the subject, taking into account its needs, its social relations, as well as its material and subjective conditions of existence, so that it chooses to understand its suffering, from the space closest to its daily life: the community. This aims to contribute to the discussions on conditions that promote well-being and psychological distress, the history of psychiatric institutionality, clinical approach, and community care in mental health. This article is part of research on the history of the hospital, which is carried out in conjunction with the University of Costa Rica (UCR) and the CCSS, specifically at the Social Research Institute (IIS) and the Dr. Roberto Chacón Paut Hospital. It is based on a methodology that integrates a review of scientific literature, an analysis of the discourse of the newspaper library, and interviews.

On the scaling patterns of infectious disease incidence in cities

Oscar Patterson-Lomba, Andrés Gómez-Lievano — Wed, 27 Sep 2023 00:00:00 -0600

Urban areas with larger and more connected populations offer an auspicious environment for contagion processes such as the spread of pathogens. Empirical evidence has revealed a systematic increase in the rates of certain sexually transmitted diseases (STDs) in urban areas with larger population sizes. With rampant urbanization worldwide, it is increasingly important to improve our understanding of the key drivers of these systemic infection patterns. Using confirmed-case data for three STDs in U.S. metropolitan areas, we investigate the scaling patterns of the incidence of these infectious diseases in urban areas. The most salient features of these patterns are that, on average, the incidence of infectious diseases that transmit with less ease i) scale more steeply with population size, ii) are more variable across cities of similar size, and iii) are less predictable across time. These features are explained using a simple mathematical model of contagion and also through the lens of a new theory of urban scaling. These theoretical frameworks help us reveal the links between the factors that determine the transmissibility of infectious diseases and the properties of their scaling patterns across cities.

Patrones de movilidad en tiempos de COVID-19

Sun, 02 Jul 2023 00:00:00 -0600

La movilidad en Costa Rica es un tema complejo debido a la falta de ordenamiento territorial de la Gran Área Metropolitana (GAM). La crisis sanitaria global causada por la pandemia del COVID-19 cambió considerablemente los patrones de movilidad en el país a causa de restricciones vehiculares, y de actividades económicas, impuestas por el gobierno para contener los contagios del virus. Con el uso de las técnicas de \textit{big data} y los datos de Waze, se analiza la congestión vial (como \textit{proxy} de la movilidad de población) antes (2019) y durante la pandemia (marzo a diciembre de 2020). Además, se analiza la relación entre los flujos de movilidad de la población, junto con variables sociodemográficas, y los contagios de COVID-19. Los análisis realizados muestran que la movilidad de población cambió drásticamente con la pandemia, y que la movilidad y las variables sociodemográficas estudiadas están asociadas con la cantidad de contagios por COVID-19. Estos resultados sirven como una inspección del fenómeno ocurrido tan complejo, y también como un insumo para valorar la factibilidad de aplicar medidas sobre el tránsito en condiciones posteriores a la pandemia, con el fin de reducir los tiempos perdidos por la congestión, la contaminación y otras externalidades negativas que produce el fuerte embotellamiento en la GAM.

Can we use the lessons of the pandemic to face the next humanitarian crises, now?

Gustavo Mery — Wed, 28 Jun 2023 00:00:00 -0600

The COVID-19 pandemic is only one devastating example of the pressing need to effectively apply science to solve real-world problems in today’s global environment. Mathematical modelling applied to population health research and management is one effective tool to bridge that gap, but we are not using it to its full potential. This article presents a reflection on some lessons from successfully applying mathematical models to guide decision-making during the COVID-19 pandemic in Costa Rica. We assembled an inter- and cross-disciplinary team with three key characteristics: robust cutting-edge technical skills for mathematical modelling, an effective pathway to communicate with the decision-makers, and the capacity to translate what the decision-makers needed to know into parameters in the model, and vice versa. Lessons from this experience can guide on how to transform the use of mathematics to understand and improve population health and its determinants, to help us face the next humanitarian crises, now.