A discrete model for the evaluation of public policies: The case of Colombia during the COVID-19 pandemic.

In mathematical epidemiology, it is usual to implement compartmental models to study the transmission of diseases, allowing comprehension of the outbreak dynamics. Thus, it is necessary to identify the natural history of the disease and to establish promissory relations between the structure of a mathematical model, as well as its parameters, with control-related strategies (real interventions) and relevant socio-cultural behaviors. However, we identified gaps between the model creation and its implementation for the use of decision-makers for policy design. We aim to cover these gaps by proposing a discrete mathematical model with parameters having intuitive meaning to be implemented to help decision-makers in control policy design. The model considers novel contagion probabilities, quarantine, and diffusion processes to represent the recovery and mortality dynamics. We applied mathematical model for COVID-19 to Colombia and some of its localities; moreover, the model structure could be adapted for other diseases. Subsequently, we implemented it on a web platform (MathCOVID) for the usage of decision-makers to simulate the effect of policies such as lock-downs, social distancing, identification in the contagion network, and connectivity among populations. Furthermore, it was possible to assess the effects of migration and vaccination strategies as time-dependent inputs. Finally, the platform was capable of simulating the effects of applying one or more policies simultaneously.

[Estimation of serial interval and basic reproductive number for imported cases of COVID-19]. / Estimación del intervalo serial y número reproductivo básico para los casos importados de COVID-19.

OBJECTIVE: To estimate the serial interval and the basic reproduction number of COVID-19 between imported cases during the containment phase in Pereira-Colombia, 2020. METHOD: A quantitative study was carried out to determine the transmission dynamics for COVID-19. Field epidemiological data were used, which included 12 laboratory-confirmed cases with RT-PCR for imported SARS-CoV-2 and their corresponding confirmed secondary cases, including family and social contacts. RESULTS: The serial intervals in COVID-19 fit a Gamma distribution, with a mean of the serial interval of 3.8 days (2.7) and an R0 of 1.7 (95% CI 1.06-2.7) lower than that found in other populations with onset of the outbreak. CONCLUSIONS: A serial interval lower than the incubation period such as that estimated in this study, suggests a presymptomatic transmission period that according to other investigations reaches an average peak at 3.8 days, suggesting that during the field epidemiological investigation the search for contacts Narrowing is performed from at least 2 days before the onset of symptoms of the initial case.

[SARS-coV-2 spatio - temporal analysis in Cali, Colombia]. / Análisis espacio-temporal del SARS-COV-2 en Cali, Colombia.

OBJECTIVE: To describe the spatio-temporal distribution of the COVID-19 in the city of Cali during the first month of the epidemic. METHODS: An exploratory analysis of spatial data was carried out, consisting of a kernel density analysis and the presence of spatial patterns was verified by the K-Ripley function. RESULTS: The spatial distribution of the cases tends to initially concentrate in the north and south of the city, with a changing dynamic towards the east and west. CONCLUSIONS: The identified spatial pattern may be influenced by the isolation measures taken at the local and national level, but the effect of the low access of the general population to diagnostic tests, delays and restraints to know the results cannot be ruled out and even possible biases due to difficulties in the technique of taking the sample or its conservation.

[Behavior by sex and gender of the COVID-19 pandemic in Colombia]. / Comportamiento por sexo y género de la pandemia de COVID-19 en Colombia.

OBJECTIVE: To determine the importance of mainstreaming from the perspective of sex-gender and age to recognize the differences and their inequality in the current situation of COVID-19. MATERIALS AND METHODS: Quantitative, exploratory, non-experimental, cross-sectional approach. Polynomial regressions were determined that better explain the current trends for sex-gender and age, the corresponding R2 was calculated. RESULTS: The trends of confirmed contagion cases are very similar between men and women. In deaths there is a greater relationship between men than women. Regarding age, there are differences in confirmed cases concentrated between 21 and 60 years and in those who died in those over 50 years of age. CONCLUSIONS: The COVID-19 pandemic affects both sexes. However, the number of death men is higher than that of women. Regarding age, contagion is concentrated between 21 and 60 years, mortality in over 50 years. The information provided by the National Institute of Health of Colombia is limited, but it has good characteristics in age groups, although improvements can be made based on sex-gender in terms of race, health personnel, the military, and the policemen infected by COVID-19.

OBJETIVO: Determinar la importancia de la transversalidad desde la prespectiva del sexo-género y edad para reconocer las diferencias y su desigualdad en la actual situación de COVID-19. MATERIALES Y MÉTODOS: Enfoque cuantitativo, exploratorio, no experimemental, de corte transversal. Se determinaron regresiones polinomiales que explican mejor las tendencias actuales para sexo-género y edad y se calculó el correspondiente R2. RESULTADOS: Las tendencias de casos de contagios confirmados son muy similares entre hombres y mujeres. En fallecimientos, existe una mayor relación entre hombres que en mujeres. En cuanto a la edad, existen diferencias en los casos confirmados concentrados entre 21 y 60 años y en los fallecidos en mayores de 50 años. CONCLUSIONES: La pandemia de COVID-19 afecta a ambos sexos. Sin embargo, es más alto el número de hombres fallecidos que de mujeres. En cuanto a la edad, se concentra el contagio entre los 21 y 60 años y la mortalidad en mayores de 50 años. La información suministrada por el Instituto Nacional de Salud de Colombia es limitada, pero cuenta con buenas características en grupos de edad pese a que se pueden realizar mejoras en función del sexo-género en cuanto a raza, el personal de salud, las fuerzas militares y la policía nacional infectados de COVID-19.

[SARS-C0V.2/COVID-I9 in Colombia: tendencies, predictions, and tensions about health system]. / SARS-COV.2/COVID-19 en Colombia: tendencias, predicciones y tensiones sobre el sistema sanitario.

OBJECTIVE: To analyze the temporal progress in the early stage of COVID-19 in Colombia using the SIRD model. METHODS: We analyzed the temporal progress of COVID-19 based on the number of infected persons between March 6th and April 15th, 2020. The SIRD model was implemented with variation in the rate of transmission (b) in three ways. A. Quarantine until July 11. 2. B. Flexible quarantine, [b=4%]. C. Flexible quarantine2 [b=8%]. Consecutively, we aimed to predict the number of total cases and 5% of infected persons in ICU to match them with the hospital beds and ICU staff. RESULTS: The results show that the number of COVID-19 cases will increase from 54 105 to 116 081 approximately, if the quarantine is lifted on May 11. If the infection rate increase, more hospital beds and a bigger ICU staff will be mandatory. The currently 2 650 beds won't be enough in the flexible quarantine2, and five intensive care specialist and four nurses per patient will be needed. CONCLUSION: Measures like mandatory social distancing help delay the saturation of the health care system. However, it's impracticable to maintain them due to a possible economic crisis. Therefore, it's necessary to take action to enhance the ability of the health care system to avoid a collapse.

A postmortem study of patients vaccinated for SARS-CoV-2 in Colombia.

INTRODUCTION AND OBJECTIVE: A new coronavirus produces a disease designated as coronavirus disease 2019 (COVID-19). Vaccination against COVID-19 has resulted in decreased mortality. Postmortems of vaccinated patients play an important part in the forensic analysis of adverse effects after vaccination, which is essential for determining its efficacy and security. The main objective of this study was to describe the results of autopsies of patients vaccinated for SARS-CoV-2 carried out in two major centers in Colombia. MATERIALS AND METHODS: A descriptive cross-sectional study of 121 autopsies was performed following Colombian regulations in two main hospitals in Bogotá, Colombia, between March 1st and April 31st, 2021. RESULTS: 118 of the 121 patients (97.52%) had been vaccinated with CoronaVac (Sinovac); only 3 had received other vaccines. Sudden cardiac death was the leading cause of death, with pulmonary embolism another critical finding. No relation between the cause of death and vaccination against SARS-CoV-2 was found. CONCLUSIONS: A clinical autopsy is a vital for an accurate post-mortem diagnosis. Any relation between the SARS-CoV-2 vaccine and the cause of death should be carefully studied in order to provide the general public with evidence-based information about the safety of the vaccination.

[Mathematical models for COVID-19 infection estimation: essential considerations and projections in Colombia]. / Modelos matemáticos estimadores de la infección por COVID-19: consideraciones esenciales y proyecciones en Colombia.

OBJECTIVE: To estimate the COVID-19 infection behavior in Colombia using mathematical models. METHODS: Two mathematical models were constructed to estimate imported confirmed cases and related confirmed cases of COVID-19 infection in Colombia, respectively. The phenomenology of imported confirmed cases is modeled with sigmoidal function, while related confirmed cases are modeled using a combination of exponential functions and polynomial algebraic functions. The fitting algorithms based on least squares methods and direct search methods are used to determine the parameters of the models. RESULTS: The sigmodial model performs a highly convergent estimation of the reported confirmed cases of COVID-19 infection to May 28, 2020. This model achieved a prediction error of 0.5 % measured using the normalized root mean square error. The model of the confirmed cases reported as related shows a 3.5 % prediction error and a low bias of -0.01 associated with overestimation. CONCLUSIONS: This work shows that the mathematical models allow to predict the behavior of the infection efficiently and effectively by COVID 19 in Colombia when the imported cases and the related cases of infection are independently considered.

OBJETIVO: Estimar el comportamiento de la infección por COVID-19 en Colombia mediante modelos matemáticos. MÉTODOS: Se construyeron dos modelos matemáticos para estimar los casos confirmados importados y los casos confirmados relacionados de la infección por COVID-19 en Colombia, respectivamente. La fenomenología de los casos confirmados importados es modelada con una función sigmoidal, mientras que los casos confirmados relacionados son modelados mediante una combinación de funciones exponenciales y funciones algebraicas polinomiales. Se utilizan algoritmos de ajuste basados en métodos de mínimos cuadrados y métodos de búsqueda directa para la determinación de los parámetros de los modelos. RESULTADOS: El modelo sigmodial realiza una estimación altamente convergente de los datos reportados, al 28 de mayo de 2020, de los casos confirmados importados de infección por COVID-19. El modelo muestra un error de predicción de 0,5%, que se mide usando la raíz del error cuadrático medio normalizado. El modelo para los casos confirmados reportados como relacionados muestra un error en la predicción del 3,5 % y un sesgo bajo del -0,01 asociado a la sobrestimación. CONCLUSIONES: El presente trabajo evidencia que los modelos matemáticos permiten eficaz y efectivamente predecir el comportamiento de la infección por COVID-19 en Colombia cuando los casos importados y los casos relacionados de infección son consideradores de manera independiente.

An interactive web-based dashboard to track COVID-19 in Colombia. Case study: five main cities.

OBJECTIVE: Design and implement an interactive web-based dashboard to track COVID-19 in Colombia. METHODS: A tool was designed and implemented to analyze the data of Covid-19 positive cases in Colombia and published by the Instituto Nacional de Salud. The tool is based on the implementation of business intelligence methods with which you can understand the behavior of the pandemic in Colombia and generate structured data for decision-making by government levels. The tool displays, on a single screen, information on the number of cases, patient status, age ranges, city, location department, and gender. This information can be dynamically filtered and focus analyzes on the national, departmental, or municipal order. Additionally, methods are implemented for trend analysis, both on a linear and semi-log scale, as well as for calculating the case fatality rate in each of the municipalities. RESULTS: A web-based data analysis dashboard is implemented for semi-continuous monitoring of the COVID-19 pandemic in Colombia. With the use of the tool, a situational analysis is carried out for five of the most important cities in Colombia. CONCLUSIONS: The application is effective, flexible, and easy to use. The situational analysis reflects that public policies for the control of the disease have been favorable for Medellín, but for Cartagena, Bogotá, Barranquilla, and Cali, complementary measures are required.

[Underlying conditions on the southern border between Colombia and Venezuela to face the COVID-19 pandemic]. / Condiciones en la frontera sur entre Colombia y Venezuela ante la pandemia de COVID-19.

OBJECTIVES: To size human migration on the southern border between Colombia and Venezuela (Guainía department), and characterize the social, access and health care conditions relevant to the COVID-19 pandemic. METHODS: Mixed epidemiological and ethnographic study. Rate of Venezuelan migrants was calculated according to Migration Colombia data until December 31st, 2019, also effective access to medical care, and provision of health posts were calculated, with information from each Guainía health post collected from June 2017 to June 2019, through semi-structured interviews, participant observations, Google Earth™ and Wikiloc™. Stata™ was used to calculate and graph median times of effective access. Cultural dynamics and health care conditions were described by the field work information and a permanent documentary review. RESULTS: Guainía is the 23rd department, according to the total number of Venezuelans, but the fourth in Venezuelans density (14,4%). In the Guainía river, the median times to the real reference health institution were 8,7 hours in winter and 12,3 in summer, and complex cases require air referrals. In the Inírida river, the median times to the real reference health institution were 11,9 hours in winter and 16,1 in summer. Only 57% of the health posts had supplies for acute respiratory infections. CONCLUSIONS: Facing COVID-19 in south border territories, it is necessary to immediately strengthen medical and public health services to avoid high fatality rates.

[Impact of the COVID-19 pandemic on the Colombian population according to mitigation measures. Preliminary data from epidemiological models for the period March 18 to April 18, 2020]. / Proyecciones de impacto de la pandemia COVID-19 en la población colombiana, según medidas de mitigación. Datos preliminares de modelos epidemiológicos para el periodo del 18 de marzo al 18 de abril de 2020.

INTRODUCTION: First case of COVID-19 in Colombia was diagnosed on March 6th. Two weeks later, cases have rapidly increased, leading the government to establish some mitigation measures. OBJECTIVES: The first objective is to estimate and model the number of cases, use of hospital resources and mortality by using different R0 scenarios in a 1-month scenario (from March 18 to April 18, 2020), based on the different isolation measures applied. This work also aims to model, without establishing a time horizon, the same outcomes given the assumption that eventually 70% of the population will be infected. MATERIALS AND METHODS: Data on the number of confirmed cases in the country as of March 18, 2020 (n=93) were taken as the basis for the achievement of the first objective. An initial transmission rate of R0= 2.5 and a factor of 27 for undetected infections per each confirmed case were taken as assumptions for the model. The proportion of patients who may need intensive care or other in-hospital care was based on data from the Imperial College of London. On the other hand, an age-specific mortality rate provided by the Instituto Superiore di Sanità in Italy was used for the second objective. RESULTS: Based on the 93 cases reported as of March 18, if no mitigation measures were applied, by April 18, the country would have 613 037 cases. Mitigation measures that reduce R0 by 10% generate a 50% reduction in the number of cases. However, despite halving the number of cases, there would still be a shortfall in the number of beds required and only one in two patients would have access to this resource. CONCLUSION: This model found that the mitigation measures implemented to date by the Colombian government and analyzed in this article are based on sufficient evidence and will help to slow the spread of SARS-CoV-2 in Colombia. Although a time horizon of one month was used for this model, it is plausible to believe that, if the current measures are sustained, the mitigation effect will also be sustained over time.

[Predictions of a SEIR model for COVID-19 cases in Cali-Colombia]. / Predicciones de un modelo SEIR para casos de COVID-19 en Cali, Colombia.

OBJECTIVE: To predict the number of cases of COVID-19 in the city of Cali-Colombia through the development of a SEIR model. METHODS: A SEIR compartmental deterministic model was used considering the states: susceptible (S), exposed (E), infected (I) and recovered (R). The model parameters were selected according to the literature review, in the case of the case fatality rate data from the Municipal Secretary of Health were used. Several scenarios were considered taking into account variations in the basic number of reproduction (R0), and the prediction until april 9 was compared with the observed data. RESULTS: Through the SEIR model it was found that with the highest basic number of reproduction [2,6] and using the case fatality rate for the city of 2,0%, the maximum number of cases would be reached on June 1 with 195 666 (prevalence). However, when comparing the observed with the expected cases, at the beginning the observed occurrence was above the projected, but then the trend changes decreasing the slope. CONCLUSIONS: SEIR epidemiological models are widely used methods for projecting cases in infectious diseases, however it must be taken into account that they are deterministic models that can use assumed parameters and could generate imprecise results.

[Risk of transmission of SARS-CoV-2: multi-criteria spatial evaluation in a municipality of Colombia, 2020]. / Riesgo de transmisión de SARS-CoV-2: evaluación espacial multicriterio en un municipio de Colombia, 2020.

OBJECTIVE: To zoning the risk of SARS-CoV-2 transmission in Villavicencio, Colombia, through a multi-criteria spatial evaluation. MATERIALS AND METHODS: A multi-criteria evaluation model was implemented, through a hierarchical analysis process, integrated into a Geographic Information System. As criteria, descriptive attributes of the threats and vulnerabilities of viral transmission identified by means of an epidemiological model were included, on the same dimensionless numerical scale and proportional to the probability of contagion; the alternatives evaluated correspond to spatial entities represented by pixels. The criteria were weighted according to the expert judgment of the evaluators, with whom the calculation of a normalized matrix of relative priorities was performed, which allowed the estimation of a vector of weights, the degree of inconsistency of which was admissible. The magnitude of the risk was calculated with a weighted summation of the evaluation of the criteria, according to a map algebra geoprocessing. RESULTS: The spatial heterogeneity of the risk of SARS-CoV-2 transmission was described in Villavicencio, allowing the identification of the areas with the highest probability of transmission, located in neighborhoods characterized by high socioeconomic vulnerability. CONCLUSIONS: The cartographic representation derived from the implementation of a multicriteria model, integrated to a Geographical Information System, in the SARS-CoV-2 transmission risk analysis, constitutes a relevant methodological contribution for decision-making defining strategies of mitigation at the local level, facilitating the location and optimization of resources by the health authorities.

[SIR model of the COVID-19 pandemic in Colombia]. / Modelo SIR de la pandemia de COVID-19 en Colombia.

OBJECTIVE: To develop a prognostic SIR model of the COVID-19 pandemic in Colombia. MATERIALS AND METHODS: A SIR model with a deterministic approach was used to forecast the development of the COVID-19 pandemic in Colombia. The states considered were susceptible (S), infectious (i) and recovered or deceased (R). Population data were obtained from the National Administrative Department of Statistics (DANE) - Population Projections 2018-2020, released in January 2020-, and data on daily confirmed cases of COVID-19 from the National Institute of Health. Different models were proposed varying the basic reproduction number (R0). RESULTS: Based on the cases reported by the Ministry of Health, 4 simulated environments were created in an epidemiological SIR model. The time series was extended until May 30, the probable date when 99% of the population will be infected. R0=2 is the basic reproduction number and the closest approximation to the behavior of the pandemic during the first 15 days since the first case report; the worst scenario would occur in the first week of April with R0=3. CONCLUSIONS: Further mitigation and suppression measures are necessary in the containment and sustained transmission phases, such as increased diagnostic capacity through testing and disinfection of populated areas and homes in isolation.

Reflections on the performance of the Colombian Minister of Health regarding the management of the COVID-19 pandemic, sexual and reproductive health and public health / Reflexiones acerca del desempeño del ministro de Salud de Colombia en el manejo de la pandemia de COVID-19, la salud sexual y reproductiva, y la salud pública

Objectives: To offer a critical assessment of the incumbent Health Minister's performance at the end of the Ivan Duque administration regarding the management of the pandemic, sexual and reproductive health, and public health in Colombia. Material and methods: Based on the description of challenges faced during this time period, we present evidence regarding performance results which, together with the author's opinion, offer an assessment of the work done. Conclusions: The Health Minister's performance in managing the pandemic fell short, in particular as concerns sexual and reproductive health, as well as public health.

Objetivos: hacer una evaluación crítica de la gestión del ministro de Salud en ejercicio al terminar el gobierno de Iván Duque en el manejo de la pandemia, la salud sexual y reproductiva, y la salud pública en Colombia. Materiales y métodos: a partir de la descripción de situaciones problemáticas enfrentadas en ese periodo se presenta evidencia sobre los resultados de la gestión que, sumados a la opinión del autor, proveen un balance de la gestión realizada. Conclusiones: la gestión del ministro de Salud fue deficiente en el manejo de la pandemia y, en especial, en su atención a la salud sexual y reproductiva, y la salud pública.

Diminishing returns: Nudging Covid-19 prevention among Colombian young adults.

Nonpharmaceutical interventions (NPIs) like social distancing, face masks, and handwashing will continue to be a frontline defense against Covid-19 for some time. But their effectiveness depends critically on compliance by young adults, who are most likely both to become infected and to infect others. We conducted a randomized controlled trial in Bogotá, Colombia, to assess the effectiveness of informational nudges emphasizing the private and public benefits of compliance on university students' concern about Covid-19, recent compliance with NPI recommendations, and intended future compliance. Although nudges boosted concern, they had limited effects on either recent or intended future compliance. We attribute these null results to high baseline levels of information about and compliance with NPIs, an informational diminishing returns scenario that is likely to be increasingly common globally.

Viruses responsible for acute respiratory infections before (2016-2019) and during (2021) circulation of the SARS-CoV-2 virus in pediatric patients in a reference center at Barranquilla Colombia: A pattern analysis.

OBJECTIVE: To evaluate the behavior of the viruses responsible for acute respiratory infections before (2016-2019) and after (2020-2021) the start of the circulation of the SARS-CoV-2 virus in pediatric patients treated at a reference center from Barranquilla, Colombia. MATERIALS AND METHODS: A descriptive observational study was carried out, and data were obtained by reviewing the influenza-like illness and severe acute respiratory infection database in the pediatric population of the sentinel surveillance reference center in the district of Barranquilla during the years 2016-2021, applying inclusion and exclusion criteria. RESULTS: During 2016-2019, the average age of individuals was 1.3 (±1.7) years, during 2021, it was 2.3 (±3.5) years. The distribution by sex was similar, predominantly male. August and February were the months with the highest record of symptoms for 2016-2019 and 2021, respectively, the most frequent being cough, fever, shortness of breath, and diarrhea. By 2021 there was a higher use of antibiotics and antivirals reported than in 2016-2019. Most patients tested negative for viral detection. When comparing the percentage of viruses detected by age group and years of detection, positivity was lower in 2021 by every age group, and respiratory syncytial virus (RSV) was the most frequently detected. CONCLUSIONS: There was less virus positivity in viral detection tests in the pediatric population in 2021. RSV persists as the main etiology affecting this population, especially infants. The use of antibiotic therapy in viral infections continues to be a problematic practice in their management. Sentinel surveillance can be strengthened throughout the country.

Impact of weekday and weekend mobility and public policies on COVID-19 incidence and deaths across 76 large municipalities in Colombia: statistical analysis and simulation.

BACKGROUND: Despite widespread restrictions on residents' mobility to limit the COVID-19 pandemic, controlled impact evaluations on such restrictions are rare. While Colombia imposed a National Lockdown, exceptions and additions created variations across municipalities and over time.  METHODS: We analyzed how weekend and weekday mobility affected COVID-19 cases and deaths. Using GRANDATA from the United Nations Development Program (UNDP) we examined movement in 76 Colombian municipalities, representing 60% of Colombia's population, from March 2, 2020 through October 31, 2020. We combined the mobility data with Colombia's National Epidemiological Surveillance System (SIVIGILA) and other databases and simulated impacts on COVID-19 burden.  RESULTS: During the study period, Colombians stayed at home more on weekends compared to weekdays. In highly dense municipalities, people moved less than in less dense municipalities. Overall, decreased movement was associated with significant reductions in COVID-19 cases and deaths two weeks later. If mobility had been reduced from the median to the threshold of the best quartile, we estimate that Colombia would have averted 17,145 cases and 1,209 deaths over 34.9 weeks, reductions of 1.63% and 3.91%, respectively. The effects of weekend mobility reductions (with 95% confidence intervals) were 6.40 (1.99-9.97) and 4.94 (1.33-19.72) times those of overall reductions for cases and deaths, respectively. CONCLUSIONS: We believe this is the first evaluation of day-of-the week mobility on COVID-19. Weekend behavior was likely riskier than weekday behavior due to larger gatherings and less social distancing or protective measures. Reducing or shifting such activities outdoors would reduce COVID-19 cases and deaths.

Risk factors for SARS-CoV-2 transmission in close contacts of adults at high risk of infection due to occupation: results from the contact tracing strategy of the CoVIDA epidemiological surveillance study in Bogotá, Colombia, in 2020-2021.

OBJECTIVES: To estimate the risk factors for SARS-CoV-2 transmission in close contacts of adults at high risk of infection due to occupation, participants of the CoVIDA study, in Bogotá D.C., Colombia. SETTING: The CoVIDA study was the largest COVID-19 intensified sentinel epidemiological surveillance study in Colombia thus far, performing over 60 000 RT-PCR tests for SARS-CoV-2 infection. The study implemented a contact tracing strategy (via telephone call) to support traditional surveillance actions performed by the local health authority. PARTICIPANTS: Close contacts of participants from the CoVIDA study. PRIMARY AND SECONDARY OUTCOME MEASURES: SARS-CoV-2 testing results were obtained (RT-PCR with CoVIDA or self-reported results). The secondary attack rate (SAR) was calculated using contacts and primary cases features. RESULTS: The CoVIDA study performed 1257 contact tracing procedures on primary cases. A total of 5551 close contacts were identified and 1050 secondary cases (21.1%) were found. The highest SAR was found in close contacts: (1) who were spouses (SAR=32.7%; 95% CI 29.1% to 36.4%), (2) of informally employed or unemployed primary cases (SAR=29.1%; 95% CI 25.5% to 32.8%), (3) of symptomatic primary cases (SAR of 25.9%; 95% CI 24.0% to 27.9%) and (4) living in households with more than three people (SAR=22.2%; 95% CI 20.7% to 23.8%). The spouses (OR 3.85; 95% CI 2.60 to 5.70), relatives (OR 1.89; 95% CI 1.33 to 2.70) and close contacts of a symptomatic primary case (OR 1.48; 95% CI 1.24 to 1.77) had an increased risk of being secondary cases compared with non-relatives and close contacts of an asymptomatic index case, respectively. CONCLUSIONS: Contact tracing strategies must focus on households with socioeconomic vulnerabilities to guarantee isolation and testing to stop the spread of the disease.

Variables associated with concordance or discordance for delirium diagnosis between referring and consulting physicians at a Tertiary Hospital in Colombia: Prospective observational study.

Delirium is an acute state of impaired consciousness and a medical urgency. Its broad range of alterations in mental status make diagnosis challenging. Awareness and accurate provisional diagnosis by nonpsychiatric clinicians are important for prompt management. Because delirium symptoms overlap and mimic other neuropsychiatric conditions, a referral to a consultant psychiatrist is often needed. The aim of this study was to determine the discriminating variables that are associated with concordance or discordance for a DSM-5 delirium diagnosis made by the consultation/liaison (C/L) psychiatrist as compared to the referral diagnosis/reasons given by the referring physicians for inpatients from a Tertiary Hospital in a Latin-American country. Prospective study of a cohort of 399 consecutive patients admitted to any ward of a university hospital in Medellin-Colombia and referred by a specialist physician to the C/L Psychiatry service. Analyses for diagnostic concordance used a nested sample of 140 cases diagnosed with delirium by the psychiatrist. Two multivariate logistic models were run, for delirium diagnosis concordance and discordance between the referring physician and C/L psychiatrist. The referral diagnosis was concordant with that of Psychiatry in 90/140 patients in 64.3%, with 35.7% discordance. Increasing age (OR = 1.024) and internal medicine ward (OR = 3.0) were significantly related (Wald statistic P < .05) to concordance in the multivariate analysis whose model accuracy was 68.6%. Trauma/orthopedics ward (OR = 5.7) and SARS-CoV-2 infection (OR = 3.8) were important contributors to the model fit though not significant. Accuracy of the discordance model was 70.7%, where central nervous system (CNS) disorder (OR = 6.1) and referrals from ICU (OR = 4.9), surgery (OR = 4.6), neurology/neurosurgery (OR = 5.1) and another consultant (OR = 4.7) were significantly related (Wald statistic P < .05), while metabolic/endocrine disorder (OR = 2.7) was important for model fit, but not significant. Concordance for delirium diagnosis was higher from services where education, guidelines and working relationships with C/L Psychiatry could have contributed beneficially whereas, surprisingly, CNS disorders and neurology/neurosurgery services had higher discordance, as well as the ICU. Routine use of brief sensitive delirium assessment tools such as the DDT-Pro could enhance provisional delirium diagnosis.