Assessment of Factors Influencing Personal Exposure to Air Pollution on Main Roads in Bogota: A Mixed-Method Study.

Background and Objectives: Particulate Matter (PM), particles of variable but small diameter can penetrate the respiratory system via inhalation, causing respiratory and/or cardiovascular diseases. This study aims to evaluate the association of environmental particulate matter (PM2.5) and black carbon (BC) with respiratory health in users of different transport modes in four roads in Bogotá. Materials and Methods: this was a mixed-method study (including a cross sectional study and a qualitative description of the air quality perception), in 300 healthy participants, based on an exploratory sequential design. The respiratory effect was measured comparing the changes between pre- and post-spirometry. The PM2.5 and black carbon (BC) concentrations were measured using portable devices. Inhaled doses were also calculated for each participant according to the mode and route. Perception was approached through semi-structured interviews. The analysis included multivariate models and concurrent triangulation. Results: The concentration of matter and black carbon were greater in bus users (median 50.67 µg m-3; interquartile range (-IR): 306.7). We found greater inhaled dosages of air pollutants among bike users (16.41 µg m-3). We did not find changes in the spirometry parameter associated with air pollutants or transport modes. The participants reported a major sensory influence at the visual and olfactory level as perception of bad air quality. Conclusions: We observed greater inhaled doses among active transport users. Nevertheless, no pathological changes were identified in the spirometry parameters. People's perceptions are a preponderant element in the assessment of air quality.

Psychosocial risk profiles to address future health emergencies: a country study during the COVID-19 lockdown period in Colombia.

Introduction: The different strategies used worldwide to curb the COVID-19 pandemic between 2020 and 2021 had a negative psychosocial impact, which was disproportionately higher for socially and economically vulnerable groups. This article seeks to identify the psychosocial impact of the confinement period during the COVID-19 pandemic for the Colombian population by identifying profiles that predict the levels of different mental health indicators (feelings of fear, positive emotions or feelings during free time, and work impact) and based on them, characterize the risk factors and protection that allows us to propose guidelines for prevention or recovery from future health emergencies. Methods: This is an observational, cross-sectional, retrospective ex post facto study. Multistage cluster probabilistic sampling and binary logistic regression analysis were used to predict extreme levels of various mental health indicators based on psychosocial indicators of the COVID-19 confinement period and to identify risk and protection factors. Results: A relationship was established between the combination of some of the different psychosocial factors evaluated (this combination being the predictive profile identified) with each of the three main variables: feeling of fear (n = 8,247; R = 0.32; p = 0.00; Poverall = 62.4%; 𝜔overall = 0.25; 1-𝛽overall = 1.00), positive emotions or feelings during free time (n = 6,853; R = 0.25; p = 0.00; Poverall = 59.1%; 𝜔overall = 0.18; 1-𝛽overall = 1.00) and labour impact (n = 4,573; R = 0.47; p = 0.63; Poverall = 70.4%; 𝜔overall = 0.41; 1-𝛽overall = 1.00), with social vulnerability determined by sociodemographic factors that were common in all profiles (sex, age, ethnicity and socioeconomic level) and conditions associated with job insecurity (unemployed, loss of health insurance and significant changes to job's requirements) and place of residence (city). Conclusion: For future health emergencies, it is necessary to (i) mitigate the socio-employment impact from emergency containment measures in a scaled and differentiated manner at the local level, (ii) propose prevention and recovery actions through psychosocial and mental health care accessible to the entire population, especially vulnerable groups, (iii) Design and implement work, educational and recreational adaptation programs that can be integrated into confinement processes.

The Effects of Nature Exposure Therapies on Stress, Depression, and Anxiety Levels: A Systematic Review.

BACKGROUND: Mental well-being plays a pivotal role within the broader spectrum of health and illness, encompassing factors such as stress, depression, and anxiety. Nature-based therapeutic interventions have emerged as a promising approach to addressing these mental health challenges. This study seeks to assess the impact of these interventions on stress, depression, and anxiety levels. METHODS: We conducted an extensive search for randomized clinical trials that examined stress, anxiety, and depression levels. The selected studies underwent a rigorous risk-of-bias assessment following the guidelines outlined in the Cochrane Handbook for Systematic Reviews. RESULTS: Our review encompassed findings from eight publications. Among them, two studies measuring cortisol levels revealed significant differences between the pre-test and post-test measurements within the intervention groups. In two studies that employed the Stress Response Inventory, a significant decrease in stress levels was observed within the intervention groups in contrast to the control groups. However, no significant differences were noted in studies that utilized the Restorative Outcome Scale. In the assessment of anxiety and depression levels, three studies employed the Positive and Negative Affect Schedule, while four studies utilized The Profile of Mood States scale; none of these studies demonstrated significant differences. CONCLUSIONS: The current body of evidence offers limited support for advocating nature-based therapeutic interventions as a primary approach to reducing stress, depression, and anxiety.

Assessment of Personal Exposure to Particulate Air Pollution in Different Microenvironments and Traveling by Several Modes of Transportation in Bogotá, Colombia: Protocol for a Mixed Methods Study (ITHACA).

BACKGROUND: Air pollution in most countries exceeds the levels recommended by the World Health Organization, causing up to one-third of deaths due to noncommunicable diseases. Fine particulate matter (PM2.5) and black carbon (BC) from mobile sources are the main contaminants. OBJECTIVE: The aim of this study is to assess the relationship of exposure to air pollutants (PM2.5 and BC) in microenvironments according to respiratory health and physical activity in users traveling by different types of transportation in Bogotá, Colombia. METHODS: A mixed methods study based on a convergent parallel design will be performed with workers and students. The sample will include 350 healthy transport users traveling by different urban transportation modes in three main routes in Bogotá. The study is broken down into two components: (1) a descriptive qualitative component focused on assessing the individual perception of air pollution using semistructured interviews; and (2) a cross-sectional study measuring the individual exposure to PM2.5 and BC using portable instruments (DustTrak and microAeth, respectively), pulmonary function by spirometry, and physical activity with accelerometry. The analysis will include concurrent triangulation and logistic regression. RESULTS: The findings will be useful for the conception, design, and decision-making process in the sectors of health and mobility from public, academy, and private perspectives. This study includes personal measurements of PM2.5 and BC during typical trips in the city to assess the exposure to these contaminants in the major roadways in real time. The study further compares the performance of two different lung tests to identify possible short-term respiratory effects. As a limitation, the protocol will include participants from different institutions in the city, which are not necessarily representative of all healthy populations in Bogotá. In this sense, it is not possible to draw causation conclusions. Moreover, a convergent parallel design could be especially problematic concerning integration because such a design often lacks a clear plan for making a connection between the two sets of results, which may not be well connected. Nevertheless, this study adopts a procedure for how to integrate qualitative and quantitative data in the interpretation of the results and a multilevel regression. The time that participants must live in the city will be considered; this will be controlled in the stratified analysis. Another limitation is the wide age range and working status of the participants. Regional pollution levels and episodes (PM2.5) will be handled as confounding variables. The study is currently in the enrollment phase of the participants. Measurements have been made on 300 participants. Pandemic conditions affected the study schedule; however, the results are likely to be obtained by late 2022. CONCLUSIONS: This study investigates the exposure to air pollutants in microenvironments in Bogotá, Colombia. To our knowledge, this is the first mixed methods study focusing on PM2.5, BC, and respiratory health effects in a city over 2 meters above sea level. This study will provide an integration of air pollution exposure variables and respiratory health effects in different microenvironments. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/25690.

Prolonged SARS-CoV-2 nucleic acid conversion time in military personnel outbreaks with presence of specific IgG antibodies.

Coronavirus disease 2019 (COVID-19) is transmitted person-to-person mainly by close contact or droplets from respiratory tract. However, the actual time of viral shedding is still uncertain as well as the different routes of transmission. We aimed to characterize RNA shedding from nasopharyngeal and rectal samples in prolonged cases of mild COVID-19 in young male soldiers. Seventy patients from three different military locations were monitored after recommending to follow more strict isolation measures to prevent the spread of the virus. Then, nasopharyngeal, rectal, and blood samples were taken. SARS-CoV-2 RNA was detected by RT-PCR and specific antibodies by chemiluminescent immunoassays. The median nucleic acid conversion time (NACT) was 60 days (IQR: 7-85 days). Rectal swabs were taken in 60 % of patients. Seven patients (10 %) were positive in nasopharyngeal and rectal swabs, and five (7.14 %) remained positive in rectal swabs, but negative in nasopharyngeal samples. Four patients (5.71 %) that had been discharged, were positive again after 15 days. No significant difference was found in nucleic acid conversion time between age groups nor clinical classification. Maintaining distancing among different positive patients is essential as a possible re-exposure to the virus could cause a longer nucleic acid conversion time in SARS-COV-2 infections.

Seroprevalence of anti-SARS-CoV-2 antibodies in Colombia, 2020: A population-based study.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to cause very high morbidity and mortality throughout Latin American countries. However, few population-based seroprevalence surveys have been conducted to quantify attack rates and characterize drivers of transmission. METHODS: We conducted a population-based cross-sectional study to assess the seroprevalence of antibodies against SARS-CoV-2 in ten cities in Colombia between September and December 2020. The study involved multi-stage cluster sampling at each city. Participants provided a serum sample and answered a demographic and risk factor questionnaire. Prior infection by SARS-CoV-2 was ascertained using the "SARS-CoV-2 Total (COV2T) Advia Centaur - Siemens" chemiluminescence assay. FINDINGS: A total of 17863 participants from 7320 households participated in the study. Seroprevalence varied substantially between cities, ranging from 26% (95%CI 23-29 %) in Medellín to 68% (95%CI 62-74 %) in Guapi. There were no differences in seroprevalence by sex, but seropositivity was higher in certain ethnic groups. There was substantial heterogeneity in seroprevalence within cities, driven to a large extent by a strong association between socioeconomic stratum and seropositivity. INTERPRETATION: Colombia has been one of the Latin American countries most affected by the COVID-19 pandemic. This study documented very high attack rates in several Colombian cities by the end of 2020 and identified key drivers of heterogeneities including ethnicity and socioeconomic stratum. Few studies of seroprevalence of SARS-CoV-2 have been conducted in Latin America, and therefore this study contributes to the fundamental understanding of the pandemic in the region. FUNDING: The study was sponsored by, Ministerio de Ciencia y Tecnología e Innovación -CT361/2020, Ministerio de Salud y Protección Social, Fundación Universitaria del Norte, Imperial College of London, Universidad Nacional de Colombia (Sede Medellín), Universidad de Córdoba, California University, Unidad Nacional de Gestión del Riesgo, Centro de Atención y Diagnóstico de Enfermedades Infecciosas -CDI-, Centro Internacional de Entrenamiento e Investigaciones Médicas -CIDEIM-, Departamento Administrativo Nacional de Estadística - DANE, Fondo Nacional de Turismo -FONTUR-, Secretarías de Salud Departamentales, Distritales y Municipales and Instituto Nacional de Salud.

SARS-CoV-2 and RT-PCR in asymptomatic patients: Results of a cohort of workers at El Dorado International Airport in Bogotá, 2020 / [SARS-CoV-2 y RT-PCR en pacientes asintomáticos: resultados de una cohorte de trabajadores del Aeropuerto Internacional El Dorado de Bogotá, 2020].

Introduction: The 2019 coronavirus pandemic (COVID-19) has caused around 25 million cases worldwide. Asymptomatic patients have been described as potential sources of transmission. However, there are difficulties to detect them and to establish their role in the dynamics of virus transmission, which hinders the implementation of prevention strategies. Objective: To describe the behavior of asymptomatic SARS-CoV-2 virus infection in a cohort of workers at the El Dorado "Luis Carlos Galán Sarmiento" International Airport in Bogotá, Colombia. Materials and methods: A prospective cohort of 212 workers from the El Dorado airport was designed. The follow-up began in June, 2020. A survey was used to characterize health and work conditions. Every 21 day, a nasopharyngeal swab was taken to identify the presence of SARS-CoV-2 using RT-PCR. We analyzed the behavior of the cycle threshold (ORF1ab and N genes) according to the day of follow-up. Results: In the first three follow-ups of the cohort, we found an incidence of SARS-CoV-2 infection of 16.51%. The proportion of positive contacts was 14.08%. The median threshold for cycle threshold was 33.53. Conclusion: We characterized the asymptomatic SARS-CoV-2 infection in a cohort of workers. The identification of asymptomatic infected persons continues to be a challenge for epidemiological surveillance systems.

Introducción. La pandemia de COVID-19 ha ocasionado cerca de 25 millones de casos en el mundo. Se ha descrito que los pacientes asintomáticos pueden ser fuentes de transmisión. Sin embargo, es difícil detectarlos y no es claro su papel en la dinámica de transmisión del virus, lo que obstaculiza la implementación de estrategias para la prevención. Objetivo. Describir el comportamiento de la infección asintomática por SARS-CoV-2 en una cohorte de trabajadores del Aeropuerto Internacional El Dorado "Luis Carlos Galán Sarmiento" de Bogotá, Colombia. Materiales y métodos. Se diseñó una cohorte prospectiva de trabajadores del Aeropuerto El Dorado. El seguimiento se inició en junio de 2020 con una encuesta a cada trabajador para caracterizar sus condiciones de salud y trabajo. Cada 21 días se tomó una muestra de hisopado nasofaríngeo para detectar la presencia del SARS-CoV-2 mediante reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR). Se analizó el comportamiento del umbral del ciclo (cycle threshold) de los genes ORF1ab y N según el día de seguimiento. Resultados. En los primeros tres seguimientos de la cohorte se encontró una incidencia de la infección por SARS-CoV-2 del 16,51 %. La proporción de contactos positivos fue del 14,08 %. La mediana del umbral del ciclo fue de 33,53. Conclusión. Se determinaron las características de la infección asintomática por el SARSCoV-2 en una cohorte de trabajadores. La detección de infectados asintomáticos sigue siendo un reto para los sistemas de vigilancia epidemiológica.

Prevention of osteoporosis in population older than 50 from Colombia: An intervention model from a nutrieconomics perspective

Introduction: Osteoporosis is a chronic disease characterized by a decrease in the density of bone mass, making bone more porous, less resistant and of lower quality than normal bone. This leads to the deterioration of its microstructure, making the bone more fragile and therefore increasing the risk of fracture. It has been found that high concentrations of Lactobacillus and Bifidobacterium promote the absorption of minerals such as calcium, magnesium, and phosphorus and thus increase mineral density. Due to the great social and economic impacts of osteoporosis, it is necessary to develop interventions that can be easily adopted at the population level, improving the quality of life of individuals without significantly affecting the health system. Objective: Assessing the impact of increased dairy consumption on the Colombian population diagnosed with osteoporosis between 2015 and 2020 through the simulation of the potential impact fraction (PIF). Methods: Using data from the Integrated Social Protection Information System (SISPRO) and National Nutritional Situation Survey (ENSIN), the incidence, the frequency of milk consumption, the potential impact fraction (PIF), and disability-adjusted life years (DALYs) were estimated. Results: A total of 63,640 cases of osteoporosis were identified. The highest incidence was observed in 2019. Seventeen food groups were identified in the ENSIN, and the most frequent products consumed by respondents over 50 years of age were milk, cheese, and yogurt. The PIF was then analysed, with a calcium intake of 600 mg/ day, and a significant difference in the decrease in the number of cases was observed. In 2019, a higher estimated DALY loss of 9.9 was observed. In women, years of life lost due to fractures were the highest in the 65-69 age group. In men, they were highest in the 75-79 age group. Discussion: We observed that the departments with the highest consumption of dairy products were the capital of the country and regions where dairy products factories are located. It was not possible to establish an association between socioeconomic strata and low dairy intake. Nevertheless, some authors have proposed that westernization of diets and low income reduce access to fresh fruits and milk derivates. Conclusion: Years lost due to disability increased in the population over 60 years of age. In the PIF analysis, a decrease in cases was observed when the population increased consumption of dairy products.

Introducción: La osteoporosis es una enfermedad crónica caracterizada por una disminución de la densidad de la masa ósea que hace que el hueso sea más poroso, menos resistente y de menor calidad que el hueso normal. Esto conduce al deterioro de su microestructura, por lo que el hueso se hace más frágil y, por lo tanto, aumenta el riesgo de fractura. Se ha encontrado que las altas concentraciones de Lactobacillus y Bifidobacterium promueven la absorción de minerales como calcio, magnesio y fósforo y, por lo tanto, aumentan la densidad mineral. Debido a los grandes impactos sociales y económicos de la osteoporosis, es necesario desarrollar intervenciones que puedan ser fácilmente adoptadas a nivel poblacional con el fin de mejorar la calidad de vida de los individuos sin afectar significativamente el sistema de salud. Objetivo: Evaluar el impacto del aumento del consumo de lácteos en la población colombiana con diagnóstico de osteoporosis entre 2015 y 2020 mediante la simulación de la fracción de impacto potencial (PIF). Materiales y métodos: Estudio ecológico realizado en adultos mayores de 50 años con diagnóstico de osteoporosis. A partir de los registros del Sistema Integrado de Información de Protección Social (SISPRO) y la Encuesta Nacional de Situación Nutricional (ENSIN), se estimó la incidencia, la frecuencia de consumo de leche, el PIF y los años de vida ajustados por discapacidad (AVAD). Resultados: Se identificaron un total de 63 640 casos de osteoporosis en SISPRO, la mayor incidencia se observó en 2019. Se establecieron 17 grupos de alimentos en la ENSIN, los productos más frecuentes consumidos en población mayor de 50 años fueron leche, queso y yogur. En el cálculo del PIF se encuentra que con una ingesta de calcio de 600 mg/día se reduciría significativamente el número de casos. En 2019 se observó una mayor pérdida estimada de AVAD de 9,9. En las mujeres, los años de vida perdidos debido a fracturas fueron más altos en el grupo de edad de 65 a 69 años. En los hombres, fue más alta en el grupo de edad de 75-79 años. Discusión: Observamos que los departamentos con mayor consumo de productos lácteos fueron la capital y las regiones donde se encuentran las fábricas de productos lácteos. No fue posible establecer una asociación entre los estratos socioeconómicos y la baja ingesta de lácteos. Sin embargo, algunos autores han propuesto que la occidentalización de las dietas y los bajos ingresos reducen el acceso a frutas frescas y derivados de la leche. Conclusión: Los años perdidos por discapacidad aumentaron en la población mayor de 60 años. En el análisis PIF, se observó una disminución en los casos (reducción de 2329 casos/ año) cuando la población aumentó el consumo de productos lácteos.

Usefulness of the Diagnosis "Decreased Cardiac Output (00029)" in Patients With Chronic Heart Failure.

OBJECTIVE: To determine the clinical and construct validity of the nursing diagnosis "decreased cardiac output" (DCO) in patients with chronic heart failure. METHODS: Cross-sectional study. RESULTS: A total of 200 people were studied. The defining characteristics with the highest prevalence were as follows: arrhythmia (62.5%) and fatigue (61.5%). Adjustment measures such as infit and outfit were maintained between 0.50 and 1.56 and the total variance explained by the measures was 29.3%. CONCLUSIONS: This study determined the clinical validity of the nursing diagnosis DCO. Regarding construct validity, adjustment of the defining characteristics to the Rasch model was observed. IMPLICATIONS FOR NURSING PRACTICE: This study improves the evidence-based practice of nursing and strengthened the role of the nurse who leads care to this population. OBJETIVO: Determinar la validez clínica y de constructo del diagnóstico de enfermería "Disminución del Gasto Cardíaco" en pacientes con falla cardíaca crónica. MÉTODOS: Estudio de corte transversal. RESULTADOS: Un total de 200 pacientes fueron estudiados. Las características definitorias con las mayores prevalencias fueron: arritmia (62.5%) y fatiga (61.5%). Medidas de ajuste como el infit y outfit se mantuvieron entre 0.50 y 1.56. El total de la varianza explicada por las medidas fue de 29.3%. CONCLUSIONES: Este estudio determinó la validez clínica del diagnóstico de enfermería "Disminución del Gasto Cardíaco". En cuanto a la validez de constructo, se observó que 19 de las 21 características definitorias se ajustaron al modelo Rasch. IMPLICACIONES PARA LA PRÁCTICA DE ENFERMERÍA: Este estudio mejora la práctica basada en la evidencia de enfermería y fortalece el rol de las enfermeras que lideran el cuidado en esta población.

Analysis of COVID-19 Mortality and Survival in Colombia: A prospective Cohort Study / Análisis de la mortalidad y supervivencia para COVID-19 en Colombia: Un estudio de cohorte prospectiva

Abstract Objective: To determine the mortality and survival of COVID-19 cases in Colombia between March and July 2020. Materials and methods: A retrospective cohort study in the Colombian population between March 6 to July 8, 2020, with the data reported to the National Institute of Health. Survival analysis was performed considering the real-time PCR results, died or recovered, the onset of symptoms until the date of death, or the final time of the cohort. The actuarial variation and Long-Rank test were applied for survival. Risk factors were determined by Cox regression. Results: The overall survival rate was 100%, 98%, 97%, and 95% for day 1, 10, 20 and 30, respectively. Differences were found in survival in age, sex, region, and hospitaliza tion time spending (p <0.01), the 30-day survival rate was 96% and 95% for females and males, respectively. The region with the highest survival was Antioquia with 99% and the lower Barranquilla with 93%. The age group with the lowest survival was ≥80 years of age with 60%, and being hospitalized represented a survival rate of 68%. Conclusions: This study is one of the first to estimate survival in the Colombian population diagnosed with COVID-19.

Resumen Objetivo: determinar la mortalidad y supervivencia de casos de COVID-19 en Colombia entre marzo y julio de 2020. Materiales y métodos: Estudio de cohorte retrospectivo en población colombiana entre el 6 de marzo al 8 de julio de 2020, con los datos reportados al Instituto Nacional de Salud. El análisis de supervivencia se realizó considerando los resultados de la PCR en tiempo real, fallecido o recuperado, el inicio de los síntomas hasta la fecha del fallecimiento o el momento final de la cohorte. Para la supervivencia se aplicó la variación actuarial y la prueba de rango largo. Los factores de riesgo se determinaron mediante regresión de Cox. Resultados: La tasa de supervivencia general fue del 100%, 98%, 97% y 95% para los días 1, 10, 20 y 30, respectivamente. Se encontraron diferencias en la su pervivencia en cuanto a edad, sexo, región y tiempo de hospitalización (p <0,01), la tasa de supervivencia a 30 días fue del 96% y 95% para mujeres y hombres, respectivamente. La región con mayor supervivencia fue Antioquia con 99% y la Baja Barranquilla con 93%. El grupo de edad con menor supervivencia fue el ≥80 años con 60%, y la hospitalización representó una tasa de supervivencia del 68%. Conclusiones: Este estudio es uno de los primeros en estimar la supervivencia en la población colombiana diagnosticada con COVID-19.

SARS-CoV-2 y RT-PCR en pacientes asintomáticos: resultados de una cohorte de trabajadores del Aeropuerto Internacional El Dorado de Bogotá, 2020 / SARS-CoV-2 and RT-PCR in asymptomatic patients: Results of a cohort of workers at El Dorado International Airport in Bogotá, 2020

Introducción. La pandemia de COVID-19 ha ocasionado cerca de 25 millones de casos en el mundo. Se ha descrito que los pacientes asintomáticos pueden ser fuentes de transmisión. Sin embargo, es difícil detectarlos y no es claro su papel en la dinámica de transmisión del virus, lo que obstaculiza la implementación de estrategias para la prevención. Objetivo. Describir el comportamiento de la infección asintomática por SARS-CoV-2 en una cohorte de trabajadores del Aeropuerto Internacional El Dorado "Luis Carlos Galán Sarmiento" de Bogotá, Colombia. Materiales y métodos. Se diseñó una cohorte prospectiva de trabajadores del Aeropuerto El Dorado. El seguimiento se inició en junio de 2020 con una encuesta a cada trabajador para caracterizar sus condiciones de salud y trabajo. Cada 21 días se tomó una muestra de hisopado nasofaríngeo para detectar la presencia del SARS-CoV-2 mediante reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR). Se analizó el comportamiento del umbral del ciclo (cycle threshold) de los genes ORFlab y N según el día de seguimiento. Resultados. En los primeros tres seguimientos de la cohorte se encontró una incidencia de la infección por SARS-CoV-2 del 16,51 %. La proporción de contactos positivos fue del 14,08 %. La mediana del umbral del ciclo fue de 33,53. Conclusión. Se determinaron las características de la infección asintomática por el SARS-CoV-2 en una cohorte de trabajadores. La detección de infectados asintomáticos sigue siendo un reto para los sistemas de vigilancia epidemiológica.

Introduction: The 2019 coronavirus pandemic (COVID-19) has caused around 25 million cases worldwide. Asymptomatic patients have been described as potential sources of transmission. However, there are difficulties to detect them and to establish their role in the dynamics of virus transmission, which hinders the implementation of prevention strategies. Objective: To describe the behavior of asymptomatic SARS-CoV-2 virus infection in a cohort of workers at the El Dorado "Luis Carlos Galán Sarmiento" International Airport in Bogotá, Colombia. Materials and methods: A prospective cohort of 212 workers from the El Dorado airport was designed. The follow-up began in June, 2020. A survey was used to characterize health and work conditions. Every 21 day, a nasopharyngeal swab was taken to identify the presence of SARS-CoV-2 using RT-PCR. We analyzed the behavior of the cycle threshold (ORFlab and N genes) according to the day of follow-up. Results: In the first three follow-ups of the cohort, we found an incidence of SARS-CoV-2 infection of 16.51%. The proportion of positive contacts was 14.08%. The median threshold for cycle threshold was 33.53. Conclusion: We characterized the asymptomatic SARS-CoV-2 infection in a cohort of workers. The identification of asymptomatic infected persons continues to be a challenge for epidemiological surveillance systems.