Papers by DORACELLY HINCAPIE PALACIO
Journal of Public Health Research
Background: COVID-19 cases in Medellín, the second largest city in Colombia, were monitored durin... more Background: COVID-19 cases in Medellín, the second largest city in Colombia, were monitored during the first year of the pandemic using both mathematical models based on transmission theory and surveillance from each observed epidemic phase. Design and Methods: Expected cases were estimated using mandatory reporting data from Colombia’s national epidemiological surveillance system from March 7, 2020 to March 7, 2021. Initially, the range of daily expected cases was estimated using a Borel-Tanner stochastic model and a deterministic Susceptible-Infected-Removed (SIR) model. A subsequent expanded version of the SIR model was used to include asymptomatic cases, severe cases and deaths. The moving average, standard deviation, and goodness of fit of estimated cases relative to confirmed reported cases were assessed, and local transmission in Medellin was contrasted with national transmission in Colombia. Results: The initial phase was characterized by imported case detection and the late...
Clinical and Experimental Vaccine Research, 2022
Purpose This study aims to compare protection against diphtheria and tetanus conferred on the mot... more Purpose This study aims to compare protection against diphtheria and tetanus conferred on the mother and the neonate before and after maternal vaccination against tetanus, diphtheria, and acellular pertussis (Tdap), transfer of antibodies, and the variables that could impact on the protection. Materials and Methods The study followed a cohort of 200 pregnant women from a region in Colombia, contacted during prenatal control before vaccination and upon delivery. The work determined immunoglobulin G antibodies against diphtheria and tetanus of pregnant women and umbilical cord. The proportion of protection, the geometric mean of the concentration, and the transfer of maternal antibodies were calculated. The protection profile of the pregnant women was explored by using multiple correspondence analysis. Results The concentration of antibodies against diphtheria was significant before and after vaccination of the pregnant women (p=0.000) with proportions of 85.0% and 97.5%, respectively...
arXiv: Populations and Evolution, 2016
Introduction: Zika epidemic in America was declared a public health emergency of international co... more Introduction: Zika epidemic in America was declared a public health emergency of international concern after the rapid spread in the region. Stratification of the potential transmission of the disease is needed to address the efforts surveillance and disease control. The goal of this research is to compare the basic reproductive number of Zika in different municipalities, from an SIR model with implicit vector dynamics, based on the daily case reporting data of Antioquia, Colombia, the second most affected country after Brazil. Methods: An simple SIR model with implicit vector dynamics was derived and used. The approximate solution of the model in terms of individuals recovered in each time unit, allowed to obtain estimate of the model parameters including the basic reproduction number (Ro) and its 95% confidence intervals. These parameters were estimated via fitting the solution of the model to the daily reported cumulative cases data from the regional surveillance system. Results:...
International Journal for Computational Methods in Engineering Science and Mechanics, 2016
An analytical expression for the optimal control of an Ebola problem is obtained. The analytical ... more An analytical expression for the optimal control of an Ebola problem is obtained. The analytical solution is found as a first-order approximation to the Pontryagin Maximum Principle via the Euler-Lagrange equation. An implementation of the method is given using the computer algebra system Maple. Our analytical solutions confirm the results recently reported in the literature using numerical methods.
Tropical medicine & international health : TM & IH, Oct 7, 2017
To stratify and understand the potential transmission processes of Zika virus in Colombia, in ord... more To stratify and understand the potential transmission processes of Zika virus in Colombia, in order to effectively address the efforts on surveillance and disease control. We compare R0 , of Zika for municipalities based on data from the regional surveillance system of Antioquia, Colombia. The basic reproduction number (R0 ) and its 95% confidence intervals were estimated from an SIR model with implicit vector dynamics, in terms of recovered individuals in each time unit, using an approximate solution. These parameters were estimated fitting the solution of the model to the daily cumulative frequency of each Zika case according to symptoms onset date relative to the index case reported to the local surveillance system. R0 was estimated for 20 municipalities with a median of 30,000 inhabitants, all located less than 2,200 m above sea level. The reported cases ranged from 17 to 347 between these municipalities within four months (January to April of 2016). The results suggest that 15 ...
Smart Biomedical and Physiological Sensor Technology XII, 2015
Chikungunya fever is a global concern due to the occurrence of large outbreaks, the presence of p... more Chikungunya fever is a global concern due to the occurrence of large outbreaks, the presence of persistent arthropathy and its rapid expansion throughout various continents. Globalization and climate change have contributed to the expansion of the geographical areas where mosquitoes Aedes aegypti and Aedes albopictus (Stegomyia) remain. It is necessary to improve the techniques of vector control in the presence of large outbreaks in The American Region. We derive measures of disease control, using a mathematical model of mosquito-human interaction, by means of three scenarios: a) a single vector b) two vectors, c) two vectors and human and non-human reservoirs. The basic reproductive number and critical control measures were deduced by using computer algebra with Maple (Maplesoft Inc, Ontario Canada). Control measures were simulated with parameter values obtained from published data. According to the number of households in high risk areas, the goals of effective vector control to reduce the likelihood of mosquito-human transmission would be established. Besides the two vectors, if presence of other non-human reservoirs were reported, the monthly target of effective elimination of the vector would be approximately double compared to the presence of a single vector. The model shows the need to periodically evaluate the effectiveness of vector control measures.
SPIE Proceedings, 2008
The threshold theorem of an epidemic SIR model was compared when infectious and susceptible indiv... more The threshold theorem of an epidemic SIR model was compared when infectious and susceptible individuals have homogeneous mixing and heterogeneous social status and when individuals of random networks have contact heterogeneity. Particularly the effect of vaccination in ...
Epidemiology and Infection, 2014
SUMMARYWe simulated the frequency of tuberculosis infection in healthcare workers in order to cla... more SUMMARYWe simulated the frequency of tuberculosis infection in healthcare workers in order to classify the risk of TB transmission for nine hospitals in Medellín, Colombia. We used a risk assessment approach to estimate the average number of infections in three risk groups of a cohort of 1082 workers exposed to potentially infectious patients over 10- and 20-day periods. The risk level of the hospitals was classified according to TB prevalence: two of the hospitals were ranked as being of very high priority, six as high priority and one as low priority. Consistent results were obtained when the simulation was validated in two hospitals by studying 408 healthcare workers using interferon gamma release assays and tuberculin skin testing. The latent infection prevalence using laboratory tests was 41% [95% confidence interval (CI) 34·3–47·7] and 44% (95% CI 36·4–51·0) in those hospitals, and in the simulation, it was 40·7% (95% CI 32·3–49·0) and 36% (95% CI 27·9–44·0), respectively. Sim...
Revista de Saúde Pública, 2013
OBJECTIVE: To estimate the seroprevalence of rubella and associated factors. METHODS: Population-... more OBJECTIVE: To estimate the seroprevalence of rubella and associated factors. METHODS: Population-based seroprevalence study in a random sample of 2,124 individuals, aged six to 64 years, representative by age, sex and area in Medellín, Colombia, 2009. Biological and socioeconomic variables were analyzed for their association with serum protection against rubella, according to birth-year cohort; those born before (1954-1990) and after (1991-2003) the introduction of universal immunization. Titer of IgG antibodies against the rubella virus was detected using a high sensitivity (AxSYM ® Rubella IgG-Abbott Laboratories) and a high specificity test (VIDAS RUB IgG II ®-BioMerieux Laboratories). Proportions and weighted averages derived from a complex sample, including a correction factor for differences in gender participation, were estimated. Association with protection for groups of biological and social variables according to birth cohort was analyzed using a logistic regression model. RESULTS: Titers of IgG antibodies were higher in those born before (mean 110 UI/ml, 95%CI 100.5;120.2) compared to those born after (mean 64 UI/ml; 95%CI 54.4;72.8; p = 0.000) the introduction of mass immunization. The proportion of protection increased from 88.9% in those born 1990-1994, to 89.2% in those born 1995-1999 and to 92.1% in those born between 2000 and 2003, possibly due to boosters being administered from 1998 onwards. In those born before the introduction of the immunization, seroprotection was associated with previous contact with cases (OR 2.6; 95%CI 1.1;5.9), self-perceived health status (OR 2.5; 95%CI 1.05;6.0), educational level (OR 0.2; 95%CI 0.08;0.8) and years of residence in the neighborhood (RD 0,96; 95%CI 0.98;1.0) after adjusting for all variables. In those born after, serum protection was associated with effective sleep time (OR 1,4; 95%CI 1.09;1.8) and self-perceived health status (OR 5.5; 95%CI 1.2;23.8). CONCLUSIONS: The seroprevalence profile changed with the mass immunization plan, with higher titers of IgG antibodies in those born before the start of the immunization. It is recommended that the level of long-term protection be monitored and concerted action taken to improve potentially associated socioeconomic conditions.
Revista de Saúde Pública, 2003
OBJETIVO: Aplicar una técnica que oriente la distribución de recursos financieros del Plan de Ate... more OBJETIVO: Aplicar una técnica que oriente la distribución de recursos financieros del Plan de Atención Básico para acciones colectivas, según las condiciones de salud diferenciales. MÉTODOS: Se parte de la estimación previa de un índice global de salud mediante análisis de componentes principales, que jerarquiza las localidades de Bogotá, Colombia, en grupos según su estado de salud: "peor" estado, "intermedio" y "mejor" que los anteriores. Se aplica una técnica de mínimos cuadrados que minimice la diferencia entre el índice global de salud observado y un índice esperado con la inversión de tales recursos. RESULTADOS: Se obtiene la distribución de los recursos del Plan de Atención Básico para las veinte Localidades, destinando una cifra superior a la mediana Distrital en las Localidades con "peor" estado de salud. Además, se identifican las Localidades con déficit para el cubrimiento universal de la población de acuerdo con la destinación per ...
Revista de Saúde Pública, 2006
OBJETIVO: Estimar el ritmo reproductivo básico en un brote de varicela, aplicar el teorema umbral... more OBJETIVO: Estimar el ritmo reproductivo básico en un brote de varicela, aplicar el teorema umbral estocástico para estimar la probabilidad de la ocurrencia del brote e identificar medidas preventivas. MÉTODOS: El estudio fue realizado en una guardería de 16 niños, con 13 susceptibles, un infectado inicial y dos niños inmunes por antecedente de enfermedad. Se partió de un modelo estocástico: susceptible - infectado - removido. Se estimó el ritmo de reproducción básico de la enfermedad R0, usando un método de máxima verosimilitud basado en el conocimiento de la distribución de probabilidades para el tamaño total de la epidemia y haciendo una aproximación de epidemia casi-completa. Con el R0 obtenido se aplicó el teorema de umbral estocástico para obtener algunas medidas preventivas que podrían impedir la irrupción del brote de varicela. RESULTADOS: Cada infectado inicial produjo tres casos nuevos de infección, requiriendo para impedir el brote, una cobertura mínima de vacunación del 6...
Revista Panamericana de Salud Pública, 2012
Objective Illustrating disease transmission as a complex system according to complexity theory. M... more Objective Illustrating disease transmission as a complex system according to complexity theory. Methods A SIR mathematical model (S=number susceptible, I=number infectious, and R=number recovered or immune) reflecting disease transmission from the connection between states of susceptibility, infection, disease, recovery and
Revista Facultad Nacional De Salud Publica, 2012
Objetivo Se ilustra el proceso de transmisión de una enfermedad, entendido como un sistema comple... more Objetivo Se ilustra el proceso de transmisión de una enfermedad, entendido como un sistema complejo a la luz de la teoría de la complejidad. Métodos Se simula el comportamiento de un modelo matemático SEIR que refleja el proceso de transmisión de una enfermedad a partir de la conexión de los estados de susceptibilidad, infección, enfermedad y recuperación y no linealidad en la interacción de susceptibles e infectados. Se asume una tasa de infección con oscilaciones en el tiempo, descrito por un mapeo logístico. Resultados La transmisión transcurre en el tiempo con la reducción de los susceptibles en la medida que estos se infectan y enferman y el aumento de la recuperación tras el diagnóstico y tratamiento. Con pequeños aumentos en el valor de la tasa de infección, se observan oscilaciones en el número de susceptibles y expuestos y aleatoriedad en la relación entre los susceptibles e infectados, hasta confluir a un patrón regular. Conclusión El modelo refleja la conexión entre los estados, la no linealidad y el comportamiento caótico tras pequeños aumentos del valor de la tasa de infección. Una perspectiva histórica y transdisciplinaria ayudaría a comprender la complejidad de la transmisión y a concertar opciones de control. Palabras Clave: Dinámicas no lineales, modelos teóricos, número básico de reproducción (fuente: DeCS, BIREME).
Revista de salud pública (Bogotá, Colombia)
Illustrating disease transmission as a complex system according to complexity theory. A SIR mathe... more Illustrating disease transmission as a complex system according to complexity theory. A SIR mathematical model (S=number susceptible, I=number infectious, and R=number recovered or immune) reflecting disease transmission from the connection between states of susceptibility, infection, disease, recovery and nonlinearity in the interaction between susceptible and infected was simulated. Infection rate temporal fluctuations were described by logistic mapping. Transmission occurs with the reduction of susceptible states as people become infected and sick, followed by an increase in individuals' recovery following diagnosis and treatment. Small increases in infection rate value led to fluctuations in the number of susceptible and exposed people and randomness in the relationship between being susceptible and infected, until converging towards a regular pattern. The model reflected the connection between states of susceptibility, nonlinearity and chaotic behavior following small incre...
Revista de Salud Pública, 2010
Objective The study was aimed at comparing measles and rubella disease elimination levels in a ho... more Objective The study was aimed at comparing measles and rubella disease elimination levels in a homogeneous and heterogeneous population according to socioeconomic status with interactions amongst low-and high-income individuals and diversity in the average number of contacts amongst them. Methods Effective reproductive rate simulations were deduced from a susceptibleinfected-recovered (SIR) mathematical model according to different immunisation rates using measles (1980 and 2005) and rubella (1998 and 2005) incidence data from Latin-America and the Caribbean. Low-and high-income individuals' social interaction and their average number of contacts were analysed by bipartite random network analysis. MAPLE 12 (Maplesoft Inc, Ontario Canada) software was used for making the simulations. Results The progress made in eliminating both diseases between both periods of time was reproduced in the socially-homogeneous population. Measles (2005) would be eliminated in high-and low-income groups; however, it would only be achieved in rubella (2005) if there were a high immunity rate amongst the low-income group. If the average number of contacts were varied, then rubella would not be eliminated, even with a 95 % immunity rate. Conclusion Monitoring the elimination level in diseases like measles and rubella requires that socioeconomic status be considered as well as the population's interaction pattern. Special attention should be paid to communities having diversity in their average number of contacts occurring in confined spaces such as displaced communities, prisons, educational establishments, or hospitals.
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Papers by DORACELLY HINCAPIE PALACIO