Prediction of SARS-CoV-2 infection with a Symptoms-Based model to aid public health decision making in Latin America and other low and middle income settings.

Symptoms-based models for predicting SARS-CoV-2 infection may improve clinical decision-making and be an alternative to resource allocation in under-resourced settings. In this study we aimed to test a model based on symptoms to predict a positive test result for SARS-CoV-2 infection during the COVID-19 pandemic using logistic regression and a machine-learning approach, in Bogotá, Colombia. Participants from the CoVIDA project were included. A logistic regression using the model was chosen based on biological plausibility and the Akaike Information criterion. Also, we performed an analysis using machine learning with random forest, support vector machine, and extreme gradient boosting. The study included 58,577 participants with a positivity rate of 5.7%. The logistic regression showed that anosmia (aOR = 7.76, 95% CI [6.19, 9.73]), fever (aOR = 4.29, 95% CI [3.07, 6.02]), headache (aOR = 3.29, 95% CI [1.78, 6.07]), dry cough (aOR = 2.96, 95% CI [2.44, 3.58]), and fatigue (aOR = 1.93, 95% CI [1.57, 2.93]) were independently associated with SARS-CoV-2 infection. Our final model had an area under the curve of 0.73. The symptoms-based model correctly identified over 85% of participants. This model can be used to prioritize resource allocation related to COVID-19 diagnosis, to decide on early isolation, and contact-tracing strategies in individuals with a high probability of infection before receiving a confirmatory test result. This strategy has public health and clinical decision-making significance in low- and middle-income settings like Latin America.

Factors Associated With SARS-CoV-2 Infection in Bogotá, Colombia: Results From a Large Epidemiological Surveillance Study.

BACKGROUND: Epidemiologic surveillance of COVID-19 is essential to collect and analyse data to improve public health decision making during the pandemic. There are few initiatives led by public-private alliances in Colombia and Latin America. The CoVIDA project contributed with RT-PCR tests for SARS-CoV-2 in mild or asymptomatic populations in Bogotá. The present study aimed to determine the factors associated with SARS-CoV-2 infection in working adults. METHODS: COVID-19 intensified sentinel epidemiological surveillance study, from April 18, 2020, to March 29, 2021. The study included people aged 18 years or older without a history of COVID-19. Two main occupational groups were included: healthcare and essential services workers with high mobility in the city. Social, demographic, and health-related factors were collected via phone survey. Afterwards, the molecular test was conducted to detect SARS-CoV-2 infection. FINDINGS: From the 58,638 participants included in the study, 3,310 (5·6%) had a positive result. A positive result was associated with the age group (18-29 years) compared with participants aged 60 or older, participants living with more than three cohabitants, living with a confirmed case, having no affiliation to the health system compared to those with social health security, reporting a very low socioeconomic status compared to those with higher socioeconomic status, and having essential occupations compared to healthcare workers. INTERPRETATION: The CoVIDA study showed the importance of intensified epidemiological surveillance to identify groups with increased risk of infection. These groups should be prioritised in the screening, contact tracing, and vaccination strategies to mitigate the pandemic. FUNDING: The CoVIDA study was funded through donors managed by the philanthropy department of Universidad de los Andes.

COVID-19 spread, detection, and dynamics in Bogota, Colombia.

Latin America has been severely affected by the COVID-19 pandemic but estimations of rates of infections are very limited and lack the level of detail required to guide policy decisions. We implemented a COVID-19 sentinel surveillance study with 59,770 RT-PCR tests on mostly asymptomatic individuals and combine this data with administrative records on all detected cases to capture the spread and dynamics of the COVID-19 pandemic in Bogota from June 2020 to early March 2021. We describe various features of the pandemic that appear to be specific to a middle income countries. We find that, by March 2021, slightly more than half of the population in Bogota has been infected, despite only a small fraction of this population being detected. The initial buildup of immunity contributed to the containment of the pandemic in the first and second waves. We also show that the share of the population infected by March 2021 varies widely by occupation, socio-economic stratum, and location. This, in turn, has affected the dynamics of the spread with different groups being infected in the two waves.

Serosurveillance for vaccine-preventable diseases: A look inside the pertussis experience / Serovigilancia de enfermedades prevenibles por vacunación: una mirada desde la experiencia con la tosferina

INTRODUCTION: Serological surveillance (serosurveillance) provides the most direct measure of herd immunity of vaccine-preventable diseases. Little is known about the opportunities and challenges of serosurveillance experiences, particularly pertussis. OBJECTIVE: To describe the process of serosurveillance for vaccine-preventable diseases with an emphasis on the experience of pertussis in the metropolitan area of Antioquia (Valle de Aburrá) in 2015 and 2016 and analyze the contributions and challenges for its sustainability. MATERIALS AND METHODS: We described the planning and conduction of serosurveillance of pertussis antibodies of mothers and in the umbilical cord at the time of delivery in eight hospitals based on random sampling and their capacity to advance the serosurveillance periodically. We compared the contributions and the challenges of this experience with other probabilistic and non-probabilistic programs. RESULTS: We achieved the participation of hospitals and mothers respecting the delivery care process. We established a serum bank following ethical and technical guidelines. This program based on the random selection of hospitals and mothers has enabled the estimation of antibodies prevalence in mothers and in the umbilical cord, which has been possible given the high coverage of hospital care during childbirth at a lower cost and fewer risks than a population-based survey in conflictive areas. The main challenges for the sustainability of this program are the creation of stable jobs and access to funding and legal and methodological long-term frameworks. CONCLUSIONS: Hospital serosurveillance as described is an option to monitor the impact of vaccination on the population. Our experience could be reproduced in other regions under similar conditions if the above-mentioned challenges are solved.

Introducción. La vigilancia serológica es la forma más directa de medir la inmunidad de rebaño frente a las enfermedades prevenibles por vacunación. Poco se sabe acerca de las oportunidades y los desafíos de las experiencias de serovigilancia, en general y, específicamente, la de la tosferina.Objetivo. Describir el proceso de serovigilancia de enfermedades prevenibles por vacunación con énfasis en la experiencia en el caso de la tosferina en el área metropolitana de Antioquia (Valle de Aburrá) en el 2015 y el 2016 y analizar lo que dicha experiencia ha aportado y los desafíos que persisten para su sostenibilidad.Materiales y métodos. Se describió el proceso de planeación y el desarrollo de la serovigilancia de tosferina en el momento del parto en ocho hospitales seleccionados al azar, así como la capacidad para adelantar el programa de manera periódica. Se compararon los aportes y los desafíos en el curso de esta experiencia con los de otros programas poblacionales probabilistas e institucionales no probabilistas.Resultados. Se logró la participación de los hospitales y de las madres con pleno respeto del proceso de atención del parto, y se conformó un banco de sueros siguiendo lineamientos éticos y técnicos. El programa permitió estimar la prevalencia de anticuerpos en la madre y en el cordón umbilical, lo que se facilitó por la alta cobertura de atención hospitalaria del parto, a un menor costo y menos riesgos que los programas poblacionales en zonas conflictivas. Los principales desafíos para la sostenibilidad del programa son la estabilidad laboral del personal de salud, así como normas y una financiación de largo plazo.Conclusiones. La serovigilancia hospitalaria es una opción para monitorizar el impacto poblacional de la vacunación. Esta experiencia se podría extender a otras regiones en condiciones similares si se resuelven los retos mencionados.

Serosurveillance for vaccine-preventable diseases: A look inside the pertussis experience / Serovigilancia de enfermedades prevenibles por vacunación: una mirada desde la experiencia con la tosferina

Abstract Introduction: Serological surveillance (serosurveillance) provides the most direct measure of herd immunity of vaccine-preventable diseases. Little is known about the opportunities and challenges of serosurveillance experiences, particularly pertussis. Objective: To describe the process of serosurveillance for vaccine-preventable diseases with an emphasis on the experience of pertussis in the metropolitan area of Antioquia (Valle de Aburrá) in 2015 and 2016 and analyze the contributions and challenges for its sustainability. Materials and methods: We described the planning and conduction of serosurveillance of pertussis antibodies of mothers and in the umbilical cord at the time of delivery in eight hospitals based on random sampling and their capacity to advance the serosurveillance periodically. We compared the contributions and the challenges of this experience with other probabilistic and non-probabilistic programs. Results: We achieved the participation of hospitals and mothers respecting the delivery care process. We established a serum bank following ethical and technical guidelines. This program based on the random selection of hospitals and mothers has enabled the estimation of antibodies prevalence in mothers and in the umbilical cord, which has been possible given the high coverage of hospital care during childbirth at a lower cost and fewer risks than a population-based survey in conflictive areas. The main challenges for the sustainability of this program are the creation of stable jobs and access to funding and legal and methodological long-term frameworks. Conclusions: Hospital serosurveillance as described is an option to monitor the impact of vaccination on the population. Our experience could be reproduced in other regions under similar conditions if the above-mentioned challenges are solved.

Resumen Introducción. La vigilancia serológica es la forma más directa de medir la inmunidad de rebaño frente a las enfermedades prevenibles por vacunación. Poco se sabe acerca de las oportunidades y los desafíos de las experiencias de serovigilancia, en general y, específicamente, la de la tosferina. Objetivo. Describir el proceso de serovigilancia de enfermedades prevenibles por vacunación con énfasis en la experiencia en el caso de la tosferina en el área metropolitana de Antioquia (Valle de Aburrá) en el 2015 y el 2016 y analizar lo que dicha experiencia ha aportado y los desafíos que persisten para su sostenibilidad. Materiales y métodos. Se describió el proceso de planeación y el desarrollo de la serovigilancia de tosferina en el momento del parto en ocho hospitales seleccionados al azar, así como la capacidad para adelantar el programa de manera periódica. Se compararon los aportes y los desafíos en el curso de esta experiencia con los de otros programas poblacionales probabilistas e institucionales no probabilistas. Resultados. Se logró la participación de los hospitales y de las madres con pleno respeto del proceso de atención del parto, y se conformó un banco de sueros siguiendo lineamientos éticos y técnicos. El programa permitió estimar la prevalencia de anticuerpos en la madre y en el cordón umbilical, lo que se facilitó por la alta cobertura de atención hospitalaria del parto, a un menor costo y menos riesgos que los programas poblacionales en zonas conflictivas. Los principales desafíos para la sostenibilidad del programa son la estabilidad laboral del personal de salud, así como normas y una financiación de largo plazo. Conclusiones. La serovigilancia hospitalaria es una opción para monitorizar el impacto poblacional de la vacunación. Esta experiencia se podría extender a otras regiones en condiciones similares si se resuelven los retos mencionados.

Effect of maternal immunization against pertussis in Medellin and the metropolitan area, Colombia, 2016-2017.

BACKGROUND: In 2013, pertussis immunization (Tdap) for pregnant women was implemented in Colombia to protect newborns in response to increased pertussis incidence. OBJECTIVE: To assess the effect of Tdap maternal immunization on the concentration of mother/umbilical cord antibodies and the occurrence of pertussis in infants during their first six months of life. METHODS: A cohort study in eight randomly selected hospitals in Medellin and metropolitan area of Antioquia, Colombia was conducted in 2015-2016. IgG PT antibody levels in paired maternal and umbilical cord sera were measured from 805 mothers immunized recruited during labor and 200 mothers recruited during the prenatal care before immunization and followed until delivery. Antibodies were analyzed by commercial ELISA kits. 896 infants were followed to detect acute respiratory infections and paroxysms of coughing, inspiratory whoop, apnea, cyanosis or post-tussive vomiting. For laboratory confirmation, B. pertussis- specific real time PCR was performed. RESULTS: We observed a high prevalence of titers >100 IU/mL (mother: 18.40% [95% CI 16-21%]; umbilical cord: 23.1% [95% CI 19.2-27.4%]), positive correlation of umbilical cord and maternal antibodies, higher antibody concentration in vaccinated than in non-vaccinated mothers and significant difference in antibody levels before and after vaccination (Wilcoxon test p = 0.000). The trans placental transport ratio was higher if the mother was vaccinated between 26 and 30 weeks of pregnancy and maximum eight weeks before delivery. Two cases of pertussis were confirmed in infants (incidence of 1.99 per 1000). CONCLUSION: The expected effect of Tdap maternal vaccination against pertussis was observed.

Hepatitis B infection control in Colombian Amazon after 15 years of hepatitis B vaccination. Effectiveness of birth dose and current prevalence.

BACKGROUND: Hepatitis B virus (HBV) infection is highly endemic in the Colombian Amazon basin. In Colombia, the universal hepatitis B vaccination in that area has been active since 1993. The program targets children aged under five years. Newborns receive at least three doses, and in 2001, HBV vaccine birth dose was included. This study aimed to evaluate the advances on HBV control in the Colombian Amazon. METHODS: A population-based cross-sectional study was conducted in children less than 11 years old in rural areas of the Colombian Amazon, in order to assess the current levels of HBV prevalence and evaluate the effectiveness of HBV vaccination. Participants were selected from villages scattered along the Amazon, Putumayo and Loretoyaco Rivers. Blood samples were taken from children. All the samples were examined for surface antigen (HBsAg) and IgG antibodies against core antigen (AntiHBc) of HBV. Data on HBV vaccination status and other risk factors were also collected. RESULTS: Blood samples from 1275 children were included in the study. The positivity for IgG AntiHBC and HBsAg was 3.8% and 0.5%, respectively. It was observed that receiving a dose of HBV vaccine within 48 h after birth decreased the risk of HBV infection and carriage by 95%. Being born to an AntiHBc positive mother increased 8 times the risk of HBV infection (OR = 7.8 CI 95% 3.3-10.2) and 7 times the risk of HBsAg carriage (OR = 6.6 CI 95% 2.1-10.1). CONCLUSION: The prevalence of HBV infection and HBsAg carriage continues to decrease among children living in the Colombian Amazon. The high protective effectiveness of an HBV birth does suggest that perinatal transmission is important in endemic areas of Latin America, an aspect that has not been fully studied in the region.

Prevalencia y factores asociados a la infección por C. trachomatis, N. gonorrheae, t. vaginalis, C. albicans, sífilis, VIH y vaginosis bacteriana en mujeres con síntomas de infección vaginal en tres sitios de atención de Bogotá, Colombia, 2010 / The prevalence of and factors associated with C. trachomatis, N. gonorrheae, t. vaginalis, C. albicans infection, syphilis, Hiv and bacterial vaginosis in females suffering lower genital tract infection symptoms in three healthcare attention sites in bogotá, colombia, 2010

Objetivo: estimar la prevalencia y etiología de las infecciones de transmisión sexual, y de las infecciones endógenas en mujeres en edad reproductiva con síntomas de infección del tracto genital inferior sintomáticas, y describir los factores asociados.Materiales y métodos: estudio de corte transversal en tres centros de atención en Bogotá. Se realizó el diagnóstico etiológico mediante puntaje de Nugent para vaginosis bacteriana (VB), cultivo para Candida, y frotis en fresco para trichomonas. En un subgrupo de pacientes se realizó cultivo In Pouch TM para T. vaginalis (TV), PCR para C. trachomatis (CT) y N. gonorroheae (NG), y pruebas serológicas para sífilis y VIH. Los factores de riesgo fueron evaluados comparando los dos grupos por medio del Odds Ratio (OR) y el intervalo de confianza del 95 por ciento. Resultados: 1385 mujeres fueron incluidas, de ellas 115 (8,3 por ciento) eran trabajadoras sexuales. Se confirmó la presencia de alguna infección del tracto genital (ITG) en 731 (52,7 por ciento) de las mujeres; 560 (40,4 por ciento) presentaron infecciones endógenas y 170 (12,3 por ciento) infecciones de transmisión sexual (ITS). La etiología más frecuente fue la VB en 549 (39,6 por ciento), seguida por candidiasis en 153 (11 por ciento). CT fue detectada en 134 (9,7 por ciento y NG en 19 (1,4 por ciento). TV fue detectada por frotis en fresco en 11 (0,8 por ciento) y por cultivo en 8 de 634 (1,2 por ciento), sífilis en 12 (0,8 por ciento) y VIH en 1 (0,07 por ciento). Las mujeres trabajadoras sexuales tuvieron mayor riesgo de presentar cualquier ITS (OR: 2,0; IC 95 por ciento 1,2-3,3). Las mujeres con ITS tuvieron una edad promedio de 27,9 (± 7,8), y aquellas que no tenían ITS de 31,9 (± 8,9) años. El consumo de licor con frecuencia entre diaria y semanal fue mayor en las mujeres con ITS (OR: 2,6; IC 95 por ciento: 1,4-4,5). Conclusiones: se identificó la etiología en el 52,7 por ciento de las mujeres que consultaron por síntomas de infección del tracto genital inferior. La infección más frecuente fue vaginosis bacteriana, y clamidia dentro de la infecciones de transmisión sexual. No se identificó ninguna etiología infecciosa específica en el 47,3 por ciento de las mujeres aun cuando se utilizó el patrón de oro diagnóstico para los diferentes microorganismos.

Objective: Determining the prevalence and aetiology of sexually-transmitted infections and endogenous infections in women of childbearing age having lower genital tract infection symptoms and describing the pertinent risk factors. Materials and methods: This cross-sectional study was carried out at three outpatient healthcare centres in Bogotá, Colombia. Etiologic diagnosis was made using Nugent’s criteria for bacterial vaginosis, blood agar culture for Candida and wet mount for T. vaginalis. The In-pouch culture technique was used for T. vaginalis, the polymerase chain reaction for C. trachomatis and N. gonorroheae and serological tests for syphilis (RPR, TPHA) and HIV on a sample of the afore mentioned population. Results: 1,385 females were recruited in 2010. 115 (8.3 percent) were sex workers. An LGTI was confirmed in 731 (52.7 percent); 560 (40.4 percent) had an endogenous infection and 170 (12.3 percent) a sexually-transmitted infection (STI). The most frequent aetiology were bacterial vaginosis (39.6 percent), candidiasis (11 percent), C. trachomatis (9.7 percent) and N. gonorroheae (1.4 percent); Trichomona was detected by wet mount (0.8 percent) and culture (1.2 percent), as were syphilis (0.8 percent) and HIV (1 case). Sex workers had a higher risk of having an STI (2.0 OR; 1.2-3.3 95 percent CI), as were younger females (28 ± 7.8 cf 32 ± 8.9) (p = 0.001) and alcohol users (2.6 OR; 1.4-4.5 95 percent CI). Conclusions: Aetiology was identified for 52.7 percent of the females who consulted for lower genital tract infection symptoms; bacterial vaginosis was the most common and Chlamydia the most frequent sexually-transmitted infection. No specific aetiology was identified in almost the same number of females (47.3 percent), even when using gold-standard diagnostic technology for each microorganism.

[Chronology of a pandemic: the new influenza A (H1N1) in Bogota, 2009-2010]. / Cronología de una pandemia: la nueva Influenza A H1N1 en Bogotá, 2009-2010.

OBJECTIVES: Describing the behaviour of the A H1N1/09 virus related to time, age and gender in patients having suspected infection, medical health care and laboratory diagnosis. METHOD: This was a descriptive and retrospective study of patients diagnosed as having the influenza A H1N1/09 virus between April 2009 and July 2010 by the Bogotá Public Health Laboratory. RESULTS: The first cases of A H1N1/09 virus were confirmed since week 17, 2009; positivity increased gradually, reaching maximum expression between weeks 31-36, 2009 (43 % to 53 %) and decreased during the 37th week. The age groups most affected were 6-15 years (35.4 %) and 16-25 years (28 %) (p=0.0044); the lowest percentages were found in children aged less than 1 year (8.7 %) and people older than 65 years (7.2 %) (Chi 1.98, p=0.119). The gender ratio was similar: female (18.6 %) and male (17.6 %) (Chi 1.82, p=0.1768). CONCLUSIONS: There was a significant increase in influenza A cases during 2009. However, this did not alter the behaviour of the endemic respiratory syncytial virus; on the other hand, the H1N1/09 subtype replaced the seasonal virus circulating amongst the population of Bogotá, similarly affecting men and women, mainly young adults. The highest prevalence of cases occurred between August and September 2009.

First Colombian multicentric newborn screening for congenital toxoplasmosis.

AIMS: To determine the incidence of congenital toxoplasmosis in Colombian newborns from 19 hospital or maternal child health services from seven different cities of five natural geographic regions (Caribbean, Central, Andean, Amazonia and Eastern). MATERIALS AND METHODS: We collected 15,333 samples from umbilical cord blood between the period of March 2009 to May 2010 in 19 different hospitals and maternal-child health services from seven different cities. We applied an IgM ELISA assay (Vircell, Spain) to determine the frequency of IgM anti Toxoplasma. The results in blood cord samples were confirmed either by western blot and repeated ELISA IgM assay. In a sub-sample of 1,613 children that were negative by the anti-Toxoplasma IgM assay, the frequency of specific anti-Toxoplasma IgA by the ISAGA assay was determined. All children with positive samples by IgM, IgA, clinical diagnosis or treatment during pregnancy were recalled for confirmatory tests after day 10 of life. RESULTS: 61 positive samples for specific IgM (0.39%) and 9 positives for IgA (0.5%) were found. 143 questionnaires were positive for a clinical diagnosis or treatment for toxoplasmosis during pregnancy. 109 out of the 218 children that had some of the criteria for postnatal confirmatory tests were followed. Congenital toxoplasmosis infection was confirmed in 15 children: 7 were symptomatic, and three of them died before the first month of life (20% of lethality). A significant correlation was found between a high incidence of markers for congenital toxoplasmosis and higher mean annual rainfall for the city. CONCLUSIONS: Incidence for congenital toxoplasmosis is significantly different between hospitals or maternal child health services from different cities in Colombia. Mean annual rainfall was correlated with incidence of congenital toxoplasmosis.

Validación de pruebas ELISA IgM anti-Toxoplasma para uso en programas de tamización en recién nacidos / Validation of anti-Toxoplasma IgM ELISA tests in newborn screening programs

Objetivos. Evaluar y determinar el punto de corte para la detección de IgM anti-Toxoplasma por el método ELISA, en muestras de sangre de cordónumbilical, mediante dos ensayos comerciales diferentes, y correlacionar los resultados obtenidos con el diagnóstico de toxoplasmosis congénitarealizado por seguimiento serológico y los datos clínicos. Métodos. Se evaluó la prueba IgM anti-Toxoplasma ELISA de Vircell®, frente a los resultados por Western blot e IgM ELISA de Labsystems®. Seestudiaron 105 muestras de cordón umbilical de niños colombianos, obtenidas de seis ciudades diferentes por Western blot y seguimiento clínico yserológico en aquellos positivos. Se obtuvo una curva receptor-operador (ROC) para la prueba ELISA IgM anti-Toxoplasma de Vircell® y de Labsystems®. Se analizó la concordancia entre pruebas en 105 sueros obtenidos de cordón umbilical. Resultados. El mejor desempeño para la prueba Vircell® fue con un punto de corte de índice 8 y la prueba de Labsystems® con un punto de cortede 16 inmunounidades enzimáticas. Frente al Western blot, la prueba Vircell® tuvo una sensibilidad de 100 % (IC 95%; 71,8-100) y una especificidadde 78 % (IC 95%; 69-85,7), la prueba Labsystems® tuvo una sensibilidad de 100 % (IC95%; 71,8-100) y una especificidad de 100 % (IC95%; 96-100). Laconcordancia entre ambas pruebas (Labsystems® y Vircell®) fue de 80 %, con un índice kappa de 0,45. Conclusiones. Un punto de corte de un índice 8 para la prueba ELISA IgM anti-Toxoplasma de Vircell® y un punto de corte de 16 inmunounidadesenzimáticas por Labsystems®, permiten identificar infecciones congénitas en sangre de cordón umbilical en niños colombianos.

Objectives: To evaluate and validate the detection of anti-Toxoplasma IgM ELISA in umbilical cord blood by means of two different commercialassays and to correlate the results with the diagnosis of congenital infection in children by serological follow up and clinical data. Materials and methods: We evaluated the commercial anti-Toxoplasma IgM ELISA kitÔ from Vircell (Granada, Spain) compared to the results of Toxoplasma IgM Western blotÔ (LDbio, Lyon, France) and IgM ELISA testÔ from Labsystems (Finland). We obtained the receptor-operator curve (ROC) for the IgMELISA assay form Vircell and Labsystems. We studied 105 umbilical cord blood serum samples from Colombian children from six different cities by Westernblot, and clinical and serological follow up for positive cases. The kappa agreement index was determined for the 105 sera obtained from umbilical cords. Results: The Vircell assay showed a better performance with a cut-off index of 8 against a 16 for Labsystems for enzyme immunounits (EUI). Whenthe results were evaluated against the Western blot assay, the Vircell IgM assay had a sensitivity of 100% (IC95%: 71.8-100) and a specificity of 78%(IC95%: 69-85.7), the IgM assay from Labsystems had a sensitivity of 100% (IC95%; 71.8-100) and a specificity of 100% (IC95%; 96-100). Agreement between both tests (Labsystems and Vircell) was 80% and had a kappa index of 0.45. Conclusions: A cut-off point of 8 for the anti-Toxoplasma IgM ELISA assay from Vircell and 16 EIU for the Labsystems assay allow the identificationof congenital infections in umbilical cord blood samples from Colombian children.

Cronología de una pandemia: la nueva Influenza A H1N1 en Bogotá, 2009-2010 / Chronology of a pandemic: the new influenza A (H1N1) in Bogota, 2009-2010

Objetivo Describir el comportamiento del virus de Influenza A H1N1/09 según variables de tiempo, edad y sexo, en pacientes con sospecha de infección, atención médica y diagnóstico por laboratorio. Método Estudio descriptivo retrospectivo de pacientes diagnosticados con Influenza A H1N1/09 entre abril 2009 y julio de 2010 en el Laboratorio de salud Pública de Bogotá D.C. Resultados Se confirmaron los primeros casos de Influenza A H1N1/09 desde la semana 17 de 2009; a continuación la positividad creció gradualmente, hasta manifestar su máxima expresión entre las semanas 31 a 36 de 2009 (43 por ciento a 53 por ciento), descendiendo a partir de la semana 37. Los grupos de edad más afectados fueron los de 6 a 15 años (35,4 por ciento) y de 16 a 25 años (28 por ciento) (p=0.0044); las proporciones más bajas se hallaron en menores de 1 año (8,7 por ciento) y mayores de 65 años (7,2 por ciento) (Chi 1,98, p=0.119). La proporción por sexo fue similar: femenino (18,6 por ciento) y masculino (17,6 por ciento) (Chi 1,82, p=0.1768). Conclusiones Durante el año 2009, el virus Influenza A presentó un aumento significativo de casos; sin embargo, no modificó el comportamiento endémico del virus Sincitial Respiratorio. Por otra parte, el subtipo H1N1/09 reemplazó casi en su totalidad al virus estacional que tradicionalmente circulaba entre la población Bogotana y afectó en forma similar a hombres y mujeres, principalmente adultos jóvenes. El mayor predominio de casos se presentó entre los meses de agosto y septiembre de 2009.

Objectives Describing the behaviour of the A H1N1/09 virus related to time, age and gender in patients having suspected infection, medical health care and laboratory diagnosis. Method This was a descriptive and retrospective study of patients diagnosed as having the influenza A H1N1/09 virus between April 2009 and July 2010 by the Bogotá Public Health Laboratory. Results The first cases of A H1N1/09 virus were confirmed since week 17, 2009; positivity increased gradually, reaching maximum expression between weeks 31-36, 2009 (43 percent to 53 percent) and decreased during the 37th week. The age groups most affected were 6-15 years (35.4 percent) and 16-25 years (28 percent) (p=0.0044); the lowest percentages were found in children aged less than 1 year (8.7 percent) and people older than 65 years (7.2 percent) (Chi 1.98, p=0.119). The gender ratio was similar: female (18.6 percent) and male (17.6 percent) (Chi 1.82, p=0.1768). Conclusions There was a significant increase in influenza A cases during 2009. However, this did not alter the behaviour of the endemic respiratory syncytial virus; on the other hand, the H1N1/09 subtype replaced the seasonal virus circulating amongst the population of Bogotá, similarly affecting men and women, mainly young adults. The highest prevalence of cases occurred between August and September 2009.

Cervical cancer screening with naked-eye visual inspection in Colombia.

OBJECTIVE: To assess the accuracy of visual inspection provided by nurses through combining acetic acid (VIA) and Lugol's iodine (VILI) in a low-resource region of Colombia. METHODS: A cross-sectional study with 4957 women was conducted to evaluate visual inspection techniques as the basis for see-and-treat approaches in cervical cancer control. All women underwent conventional cytology, VIA performed by nurses, and a combination of VIA and VILI. All women underwent colposcopy and biopsies were obtained for any positive test. RESULTS: A total of 762 women underwent biopsy, 4945 women were included in the analysis of conventional cytology, and 4957 were included in the analysis of VIA and VIA-VILI. Positivity rates were 1.3% and 4.3% for HSIL and LSIL cytology, 7.4% for VIA, and 10.1% for VIA-VILI. Sensitivity for cytology was 52.9% and 36.8% for LSIL and HSIL thresholds, 53.6% for VIA, and 68.1% for VIA-VILI. The corresponding specificity was 95.0%, 99.2%, 93.2%, and 90.8% respectively. The parallel combination of VIA-VILI and cytology LSIL-threshold revealed the best performance as a screening strategy. CONCLUSION: The use of VIA-VILI simulating colposcopic procedures and provided by nurses represents a good alternative for implementing see-and-treat programs in Latin America. Program constraints should be taken into account.

Prevalencia de anormalidades citológicas e histológicas de cuello uterino en un grupo de mujeres en Bogotá, Colombia / Prevalence of cytological and histological cervical uterine abnormalities in a group of women in Bogotá, Colombia

Objetivo: Describir la prevalencia de anormalidades citológicas y de neoplasias de cuello uterino en un grupo de mujeres de Bogotá, Colombia. Métodos: Se realizó un estudio descriptivo en el que se incluyeron mujeres atendidas en centros de salud de tres localidades del sur de Bogotá, pertenecientes a estratos socioeconómicos bajos, entre 25 y 59 años de edad y con antecedente de al menos una relación sexual penetrante. Resultados: Se analizaron 4.957 casos. La edad promedio fue 39,2 años. El 69,1% de las 4.957 citologías fueron negativas, 24,7% reportaron ASC-US; 4,3%, LIE-BG; 1,2%, LIE-AG, y 0,1%, lesión sospechosa de carcinoma infiltrante. Se realizaron 762 biopsias (15,4% de la población). De éstas, 48,29% se reportaron como negativas para neoplasia, y 49,08%, con algún cambio neoplásico. La prevalencia global de neoplasias intraepiteliales y de carcinoma infiltrante fue 7,54%. La prevalencia de NIC II y NIC III fue 1,3% (0,4% y 0,9%). Se detectaron dos carcinomas infiltrantes (0,04%). Conclusiones: La prevalencia de anormalidades citológicas fue inusualmente elevada; por el contrario, los hallazgos de anormalidades histológicas (NIC I o mayor) muestran datos de alta confiabilidad, ya que son producto de biopsias tomadas por indicación de tres métodos de tamización (inspección visual, citología o colposcopia). La prevalencia de neoplasias de alto grado (NIC II y III) y cáncer infiltrante observada en nuestro estudio es mayor que la reportada para otros países.

Objective: To describe the prevalence of cytological abnormalities and neoplasias in a group of women from Bogotá, Colombia. Methods: A descriptive analysis was done among women attended health services in a low-resource area of Bogotá. All women had history of sexual onset, aged 25 to 59 years, and were investigated with conventional cytology. Results: 4,957 cases were analyzed. The average age was 39.2 years. In total 69.1% of pap smears were negative, 24.7% reported ASC-US, 4.3% LSIL, 1.2% HSIL, and 0.1% invasive cancer. 762 biopsies were done (48.29% negative and 49,08% neoplasic changes). The global prevalence of intraepithelial neoplasias and carcinoma was 7.54%. The prevalence of CIN 2 and CIN 3 was 1.3% (0.4% y 0.9%). Two invasive carcinomas were detected (0.04%). Conclusions: The prevalence of cytological abnormalities was unusually high. Histological abnormalities were investigated through three different screening methods representing highly reliable data. The prevalence of HSIL (CIN II and CIN III) and invasive cancer observed is higher than previous reports from other countries.