The decline of measles antibody titers in previously vaccinated adults: a cross-sectional analysis

ABSTRACT The global reemergence of measles in 2018-2019 reinforces the relevance of high-coverage immunization to maintain the disease elimination. During an outbreak in the Sao Paulo State in 2019, several measles cases were reported in individuals who were adequately vaccinated according to the current immunization schedule recommends. This study aimed to assess measles IgG antibody seropositivity and titers in previously vaccinated adults. A cross-sectional study was conducted at CRIE-HC-FMUSP (Sao Paulo, Brazil) in 2019. It included healthy adults who had received two or more Measles-Mumps-Rubella vaccines (MMR) and excluded individuals with immunocompromising conditions. Measles IgG antibodies were measured and compared by ELISA (Euroimmun®) and chemiluminescence (LIASON®). The association of seropositivity and titers with variables of interest (age, sex, profession, previous measles, number of measles-containing vaccine doses, interval between MMR doses, and time elapsed since the last MMR dose) was analyzed. A total of 162 participants were evaluated, predominantly young (median age 30 years), women (69.8%) and healthcare professionals (61.7%). The median interval between MMR doses was 13.2 years, and the median time since the last dose was 10.4 years. The seropositivity rate was 32.7% by ELISA and 75.3% by CLIA, and a strong positive correlation was found between the tests. Multivariate analyses revealed that age and time since the last dose were independently associated with positivity. Despite being a single-center evaluation, our results suggest that measles seropositivity may be lower than expected in adequately immunized adults. Seropositivity was higher among older individuals and those with a shorter time since the last MMR vaccine dose.

Prevalencia de toxoplasmosis en niños de entre uno y seis años de edad

Fundamento: la toxoplasmosis adquirida en niños durante los primeros años de vida es la consecuencia de la transmisión por vía oral de esta parasitosis. Objetivo: determinar la prevalencia de infección por Toxoplasma gondii en niños en los primeros años de vida y relacionarlos con variables epidemiológicas de infestación. Métodos: estudio descriptivo y transversal para examinar la presencia de anticuerpos IgG anti-Toxoplasma gondii en niños de uno a seis años de edad en el área rural del municipio Cueto durante el periodo 2020-2021. Se utilizó un muestreo probabilístico por cuotas y se recopilaron variables demográficas y epidemiológicas. Se obtuvo una muestra de 200 niños, a los que se les tomó suero a través de venopunción. Se utilizó la técnica de IFI para determinar la presencia de anticuerpos IgG anti-Toxoplasma gondii y se aplicó la prueba no paramétrica Chi-Cuadrado de Pearson para comprobar hipótesis de investigación. Resultados: la seropositividad a T. gondii fue de un 58 % en la muestra estudiada; se encontró relación entre la infestación y la convivencia con gatos domésticos y con la procedencia del agua. No se encontraron diferencias significativas en la prevalencia de T. gondii en relación con la edad, el sexo, nivel social, cultural y la higiene ambiental, consumo de carnes, frutas y hortalizas, convivencias con animales de corral. Conclusiones: se evidencia seroprevalencia a T. gondii en la población infantil de uno a seis años de edad y su relación con la procedencia del agua y la convivencia con gatos.

Foundation: acquired toxoplasmosis in children during the first years of life is the consequence of the oral transmission of this parasitosis. Objective: to determine the prevalence of Toxoplasma gondii infection in children in the first years of life and relate them to epidemiological variables of infestation. Methods: descriptive and cross-sectional study to examine the presence of IgG anti-Toxoplasma gondii antibodies in children from one to six years of age in the rural area of ​​the Cueto municipality during the period 2020-2021. Quota probabilistic sampling was used and demographic and epidemiological variables were collected. A sample of 200 children was obtained, from whom serum was taken through venipuncture. The IFI technique was used to determine the presence of IgG anti-Toxoplasma gondii antibodies and the Pearson Chi-Square non-parametric test was applied to verify research hypotheses. Results: seropositivity to T. gondii was 58% in the studied sample; A relationship was found between the infestation and the coexistence with domestic cats and with the origin of the water. No significant differences were found in the prevalence of T. gondii in relation to age, sex, social and cultural level, and environmental hygiene, consumption of meat, fruit, and vegetables, and living with farm animals. Conclusions: T. gondii seroprevalence is evidenced in the child population from one to six years of age and its relationship with the source of water and living with cats.

Severe acute respiratory syndrome coronavirus 2 seroprevalence among patients with pulmonary tuberculosis

SUMMARY OBJECTIVE: The objective of this study was to estimate the seroprevalence of severe acute respiratory syndrome coronavirus 2 antibodies in patients with tuberculosis. METHODS: This cross-sectional study was conducted at an outpatient tuberculosis clinic in Alvorada, RS, Brazil, with data collection between October and December 2020. Outpatients aged>18 years with active pulmonary tuberculosis, no prior history of coronavirus disease 2019, and no suspected coronavirus disease 2019 were included in the study. Whole blood samples were collected to perform the severe acute respiratory syndrome coronavirus 2 antibodies test. RESULTS: During the study period, 52 patients met the inclusion and were included in the analysis. Severe acute respiratory syndrome coronavirus 2 antibodies were positive in 16 (30.8%) patients. Male sex was more frequent among patients with negative severe acute respiratory syndrome coronavirus 2 antibodies than in patients with positive severe acute respiratory syndrome coronavirus 2 antibodies (86.1 vs. 56.3%, p=0.031). Contact with coronavirus disease 2019 case was more common in patients with positive severe acute respiratory syndrome coronavirus 2 antibodies compared with patients with negative severe acute respiratory syndrome coronavirus 2 antibodies (87.5 vs. 8.3%, p<0.0001). In a multivariate analysis, in a model including the variables such as male sex and contact with coronavirus disease 2019 case, only contact with coronavirus disease 2019 was independently associated with positive severe acute respiratory syndrome coronavirus 2 antibodies (OR 77.0, 95%CI 11.5-512.4, p<0.0001). CONCLUSION: This study revealed a seroprevalence of 30.8% severe acute respiratory syndrome coronavirus 2 among patients with tuberculosis.

Seropositividad de Chlamydia psittaci en trabajadores expuestos a aves y revisión de la literatura: evidencia de circulación en Antioquia / Chlamydia psittaci seropositivity in workers exposed to birds and review of the literature: Evidence of circulation in Antioquia

Introducción. La psitacosis es una enfermedad zoonótica causada por Chlamydia psittaci. Esta bacteria es catalogada como un agente con potencial bioterrorista y ha causado múltiples brotes en trabajadores con exposición laboral a aves en diferentes lugares del mundo. En Colombia, no se hace seguimiento epidemiológico de la infección y existe una gran brecha en el conocimiento. Objetivos. Determinar la frecuencia de anticuerpos contra C. psittaci en trabajadores con exposición laboral a aves y sus factores asociados. Además, revisar la literatura en relación con los estudios sobre el tema realizados en Colombia. Materiales y métodos. Se llevó a cabo un estudio descriptivo, transversal, con intención analítica, en trabajadores en contacto con aves y se revisó la literatura científica relacionada en Colombia. Se detectaron anticuerpos IgM e IgG contra C. psittaci en suero por microinmunofluorescencia. La descripción de las características sociodemográficas y de exposición se hizo con frecuencias y medidas de resumen. Se exploraron factores asociados por análisis bivariados y multivariados. La revisión de la literatura científica y gris se hizo con búsqueda estructurada. Resultados. Se analizaron 54 trabajadores en contacto con aves y se encontró una prevalencia de anticuerpos del 31,5 %. El ejercer funciones de sacrificio y faenado de las aves sin ser médico veterinario fue un factor de riesgo para la presencia de anticuerpos. Solo se encontraron cuatro estudios previos sobre C. psittaci hechos en Colombia. Conclusiones. Este estudio constituye la primera evidencia de la circulación de C. psittaci en trabajadores en contacto con aves en Antioquia y el segundo reporte en el país. Estos hallazgos aportan desde la salud pública a la estrategia One Health.

Introduction. Psittacosis is a zoonotic disease caused by Chlamydia psittaci, a bacterium classified as an agent with bioterrorist potential. It has caused multiple outbreaks in exposed poultry workers around the world. Colombia has no epidemiological follow-up of the infection and a big knowledge gap. Objectives. To determine the antibodies' frequency against C. psittaci in workers with occupational exposure to birds and to review the literature on studies conducted in Colombia. Materials and methods. We conducted a cross-sectional descriptive study with analytical intent on workers in contact with birds and reviewed the related literature in Colombia. IgM and IgG serum antibodies against C. psittaci were detected by microimmunofluorescence. The sociodemographic and exposure characteristics were expressed as frequencies and summary measures. Associated factors were explored by bivariate and multivariate analysis. The scientific and gray literature review was done with a structured search. Results. We analyzed 54 workers in contact with birds. Antibody prevalence was 31.5%. Slaughtering and evisceration by non-veterinarians was a risk factor for antibody presence. There are only four previous studies on C. psittaci in Colombia. Conclusions. Here, we present the first evidence of C. psittaci circulation among workers exposed to birds in Antioquia and the second report in the country. These findings contribute to the "One Health" public health strategy.

Vigilancia serológica de la zoonosis parasitaria en 13 regiones de la sierra del Perú: Periodo 2016-2019 / Serological surveillance of parasitic zoonoses in 13 highlands regions of Peru: Period 2016-2019

RESUMEN Objetivos. Determinar la seropositividad a anticuerpos anti-IgG por infección de Echinococcus granulosus, Fasciola hepatica y cisticerco de Taenia solium y describir las características de los infectados en 13 regiones de la sierra peruana entre 2016 y 2019. Materiales y métodos. Estudio observacional transversal, que analizó 7811 fichas epidemiológicas de la vigilancia basada en laboratorio de las zoonosis parasitarias del periodo 2016-2019. El diagnóstico se realizó mediante la detección de anticuerpos tipo IgG anti E. granulosus, F. hepatica y cisticerco de T. solium utilizando antígenos nativos mediante el ensayo inmunoabsorbente ligado a enzimas (ELISA) e Inmunoblot. La diferencia en la frecuencia de casos de estas zoonosis según características identificadas se realizó mediante la prueba chi-cuadrado de Pearson y prueba exacta de Fisher. Resultados. Se determinó una seropositividad de 7,9% para fascioliasis, 4,9% para equinococosis quística, y 2,3% para cisticerco de T. solium. Estas frecuencias fueron mayores en Cerro de Pasco para equinococosis quística (24,5%), en Ayacucho para cisticerco de T. solium (4,5%) y en Puno para fascioliasis (40,6%). Entre las características sociodemográficas, se encontró una diferencia estadísticamente significativa en la frecuencia de casos para todas las zoonosis según grupo etario, ocupación, y región de residencia. Además, se encontró diferencia con el consumo de verduras en emolientes, y entre las características clínico-epidemiológicas con tener antecedentes familiares de las zoonosis parasitarias. Conclusiones. A partir de las 7811 muestras evaluadas, se encontró que estas zoonosis parasitarias están distribuidas en 13 regiones de la sierra del Perú, ocasionando un problema de salud importante, con frecuencias que varían según diversas características.

ABSTRACT Objectives. To determine seropositivity to anti-IgG antibodies against Echinococcus granulosus, Fasciola hepatica and Taenia solium cysticercus infection and to describe the characteristics of the infected patients in 13 regions of the Peruvian highlands between 2016 and 2019. Materials and methods. Cross-sectional, observational study, in which we analyzed 7811 epidemiological records of laboratory-based surveillance of parasitic zoonoses from 2016 to 2019. Diagnosis was established by detecting IgG type anti-E. granulosus, F. hepatica and T. solium cysticercus antibodies using native antigens by enzyme-linked immunosorbent assay (ELISA) and Immunoblot. We evaluated the difference in the frequency of the cases according to identified characteristics using Pearson's chi-square test and Fisher's exact test. Results. Seropositivity was 7.9% for fascioliasis, 4.9% for cystic echinococcosis, and 2.3% for T. solium cysticercus. These rates were higher in Cerro de Pasco for cystic echinococcosis (24.5%), in Ayacucho for T. solium cysticercus (4.5%) and in Puno for fascioliasis (40.6%). Regarding the sociodemographic characteristics, we found a statistically significant difference in the frequency of cases for all zoonoses according to age group, occupation, and region of residence. We also found a difference with the consumption of vegetables in emollients, and between clinical-epidemiological characteristics and having a family history of parasitic zoonoses. Conclusions. From the 7811 samples, we found that these parasitic zoonoses are distributed in 13 regions of the Peruvian highlands, and represent a major health problem, with frequencies that change according to different characteristics.

Niveles de protección contra Haemophilus influenzae tipo b en niños, adolescentes y adultos cubanos / Levels of protection against Haemophilus influenzae type b in Cuban children, adolescents and adults

La concentración de los anticuerpos contra el polisacárido capsular polirribosilribitol fosfato del Haemophilus influenzae tipo b se considera un buen indicador serológico para evaluar protección contra la enfermedad invasiva. Existen pocos reportes que estudien la inmunidad serológica en Cuba. El objetivo general de este estudio fue determinar los niveles de protección séricos contra Haemophilus influenzae tipo b en niños, adolescentes y adultos cubanos, en una muestra de 575 individuos. Se cuantificó la concentración de IgG anti-polirribosilribitol fosfato de Haemophilus influenzae tipo b mediante un inmunoensayo enzimático estandarizado y validado en el laboratorio de inmunología del Centro Nacional de Genética Médica, La Habana, Cuba. Se determinaron las concentraciones medias geométricas de anticuerpos y los niveles de protección frente a la enfermedad invasiva por Haemophilus influenzae tipo b. La concentración media geométrica de IgG anti-polirribosilribitol fosfato fue de 1,94 μg/mL (IC95 por ciento 1,80; 2,08) y fue mayor en el grupo de 16 a 22 años. El porcentaje con protección de larga duración fue mayor para el sexo femenino que para el masculino (82,2 por ciento vs 71,4 por ciento; p=0,0339) entre los que poseían inmunidad natural. El grupo de sujetos nacidos en el periodo en que se vacunó con la vacuna conjugada cubana QUIMI-HIB® presentó concentraciones medias geométricas superiores (2,75 μg/mL, IC95 por ciento 2,00; 3,79). El 99,1 por ciento de los participantes presentó protección frente a la enfermedad invasiva por Haemophilus influenzae tipo b, el 19,8 por ciento a corto plazo y el 79,3 por ciento protección de larga duración. El inmunoensayo validado para la cuantificación de IgG anti-polirribosilribitol fosfato podría emplearse en estudios de seroprevalencia. En los sujetos estudiados, se encontró un predominio de elevadas concentraciones de IgG anti- polirribosilribitol fosfato del Haemophilus influenzae tipo b que confieren protección de larga duración(AU)

The levels of antibodies directed against the capsular polysaccharide polyribosylribitol phosphate of Haemophilus influenzae type b are considered a good serological indicator to assess the immunity against invasive disease. In Cuba, there are few reports that study serological immunity. The general objective was to determine serum protection levels against Haemophilus influenzae type b in Cuban children, adolescents and adults, in a sample of 575 Cuban individuals. The concentration of IgG against Haemophilus influenzae type b was quantified by means of an indirect ELISA standardized and validated in the immunology laboratory of the National Center of Medical Genetics, Havana, Cuba. The geometric mean concentration of IgG anti- polyribosylribitol phosphate and the levels of protection against invasive Haemophilus influenzae type b disease were determined. The geometric mean concentration of IgG anti- polyribosylribitol phosphate was 1.94 μg/mL (95percentCI 1.80;2.08) and the group from 16 to 22 years old presented the highest. Among those with natural immunity, the percentage with long-term protection was higher for females vs. males (82.2percent vs. 71.4percent; p=0.0339). The group of subjects born in the period in which they were vaccinated with the Cuban conjugate vaccine QUIMI-HIB® presented higher geometric mean concentration (2.75 μg/mL, CI95percent 2.00; 3.79). The 99.1percent of the participants had protection against invasive Haemophilus influenzae type b disease, 19.8percent short-term and 79.3percent long-term protection. The ELISA for the quantification of anti- Haemophilus influenzae type b IgG antibodies, developed and validated, could be used in seroprevalence studies. In the subjects studied, there was a predominance of high IgG anti- Haemophilus influenzae type b polyribosylribitol phosphate concentration values that confer long-term protection(AU)

Seroprevalence of SARS-CoV-2 antibodies in schoolchildren in the city of São Paulo, 2020 / Soroprevalência de anticorpos do vírus SARS-CoV-2 em escolares no município de São Paulo, 2020

ABSTRACT OBJECTIVE To estimate seroprevalence of SARS-CoV-2 antibodies in schoolchildren aged 4 to 14 years living in the city of São Paulo, according to clinical, demographic, epidemiological, and social variables, during the school closure period as a measure against covid-19 spread. METHODS A serological survey was made in September 2020 with a random sample stratified by school system (municipal public, state public and private) type. A venous blood sample was collected using the Wondfo SARS-CoV-2 Antibody Test (lateral flow method) for detection of total SARS-CoV-2 virus antibodies. Semi-structured questionnaires were applied to collect clinical, demographic, social, and epidemiological data. RESULTS Seroprevalence of SARS-CoV-2 antibodies in schoolchildren was of 16.6% (95%CI 15.4-17.8). The study found higher seroprevalence in the municipal (18.5%; 95%CI 16.6-20.6) and state (16.2%; 95%CI 14.4-18.2) public school systems compared to the private school system (11.7; 95%CI 10.0-13.7), among black and brown students (18.4%; 95%CI 16.8-20.2) and in the most vulnerable social stratum (18.5 %;95%CI 16.9-20.2). Lower seroprevalence was identified in schoolchildren who reported following the recommended protective measures against covid-19. CONCLUSION Seroprevalence of SARS-CoV-2 antibodies is found mainly in the most socially vulnerable schoolchildren. This study can contribute to support public policies that reinforce the importance of suspending face-to-face classes and developing strategies aimed at protective measures and monitoring of the serological status of those who have not yet been included in the vaccination schedule.

RESUMO OBJETIVO Estimar a soroprevalência de anticorpos do vírus SARS-CoV-2 em escolares de quatro a 14 anos de idade residentes no município de São Paulo, segundo variáveis clínicas, demográficas, epidemiológicas e sociais, durante o período de fechamento das escolas como medida de controle da covid-19. MÉTODOS Realizou-se um inquérito sorológico em setembro de 2020 com amostra aleatória estratificada por tipo de rede de ensino (pública municipal, pública estadual e privada). Foi coletada amostra de sangue venoso utilizando-se o teste de imunoensaio de fluxo lateral da fabricante Wondfo para detecção de anticorpos totais contra o vírus SARS-CoV-2. Aplicaram-se questionários semiestruturados para o levantamento de dados clínicos, demográficos, sociais e epidemiológicos. RESULTADOS A soroprevalência de anticorpos do vírus SARS-CoV-2 em escolares foi de 16,6% (IC95% 15,4-17,8). O estudo encontrou soroprevalências mais elevadas na rede pública municipal (18,5%; IC95% 16,6-20,6) e estadual (16,2%; IC95% 14,4-18,2) em relação à rede privada (11,7; IC95% 10,0-13,7) e entre escolares da raça/cor preta e parda (18,4%; IC95% 16,8-20,2) e no estrato social mais vulnerável (18,5%; IC95% 16,9-20,2). A pesquisa identificou menores soroprevalências nos escolares que relataram seguir as medidas recomendadas de proteção contra a covid-19. CONCLUSÃO A soroprevalência de anticorpos contra o vírus SARS-CoV-2 atinge principalmente os escolares socialmente mais vulneráveis. Este estudo pode contribuir para embasar políticas públicas que reforcem a importância da suspensão das aulas presenciais e da necessidade de estratégias de medidas de proteção e acompanhamento do status sorológico daqueles que ainda não foram contemplados no calendário vacinal.

Seroprevalencia de SARS-CoV-2 y factores asociados en migrantes con vocación de permanencia, Bucaramanga, Colombia / SARS-CoV-2 seroprevalence and associated factors among migrants with a vocation for permanence, Bucaramanga, Colombia / Soroprevalência de SARS-CoV-2 e fatores associados em migrantes com vocação de permanência, Bucaramanga, Colômbia

Introducción: Existen pocos reportes que evalúen la seroprevalencia contra SARS-CoV-2 en población migrante en el mundo. Estos estudios ayudan a conocer la exposición al virus en las poblaciones para implementar acciones que reduzcan el impacto de la infección por SARS-CoV-2. Objetivo: Determinar la seroprevalencia contra SARS CoV-2 en migrantes con vocación de permanencia en Bucaramanga, e identificar factores asociados a la infección previa por SARS-CoV-2. Materiales y métodos: Estudio de corte transversal analítico con muestreo consecutivo. Se incluyeron migrantes adultos en Bucaramanga durante febrero/2021. Se realizaron encuestas e inmunoensayos de quimioluminiscencia para IgM e IgG contra SARS-CoV-2 en suero. Se calcularon razones de prevalencia (RP) con regresión log-binomial. Resultados:Se incluyeron 462 participantes. La seroprevalencia de IgM fue 11,7% (IC95% 9,1­14,9), de IgG fue 32,9% (IC95% 28,8­37,3) y de IgM o IgG fue 36,1% (IC95% 31,9-40,6). Exposición a un caso confirmado (RP:1,54; IC95%1,04-2,29) o sospechoso (RP:1,56; IC95%1,13-2,16) de COVID-19, seis o más convivientes (RP:1,52; IC95%1,05-2,20), estancia en Colombia ≥2 años (RP:1,43; IC95%1,11-1,92) y presencia de síntomas (RP:1,62; IC95%1,26 - 2,10) se asociaron con mayor seroprevalencia de IgG. Discusión:En Bucaramanga, la seroprevalencia en migrantes fue similar a la de migrantes en Kuwait, pero menor que en Paris y Singapur. Conclusión: En migrantes con vocación de permanencia la seroprevalencia contra SARS-CoV-2 fue similar a la reportada en residentes de Bucaramanga. El contacto con casos sospechosos/confirmados de COVID-19 y las condiciones de hacinamiento fueron algunos de los factores asociados a la seroprevalencia.

Introduction:There are few reports assessing anti-SARS-CoV-2 seroprevalence in the migrant population in the world. These studies help to understand the exposure of populations to the virus to take actions to reduce the impact of SARS-CoV-2 infection. Objetive: To determine the anti-SARS-CoV-2 seroprevalence in migrants with a vocation for permanence in Bucaramanga and to identify factors associated with previous SARS-CoV-2 infection. Materials and Methods:Analytical cross-sectional study using consecutive sampling, which included adult migrants in Bucaramanga in February 2021. Surveys were conducted, and chemiluminescent immunoassays were performed to detect IgM and IgG antibodies to SARS-CoV-2 in serum samples. Prevalence ratios (PR) were estimated using a log-binomial regression model. Results:The study enrolled 462 participants. IgM seroprevalence was 11.7% (95% CI 9.1­14.9), IgG seroprevalence was 32.9% (95% CI 28.8­37.3), and IgM or IgG seroprevalence was 36.1% (95% CI 31.9­40.6). Contact with a confirmed case of COVID-19 (PR:1.54; 95% CI 1.04-2.29) or suspected case (PR:1.56; 95% CI 1.13­2.16); living with six or more people (PR: 1.52; 95% CI 1.05­2.20); stay in Colombia ≥ 2 years (PR:1.43; 95% CI 1.11­1.92), and presence of symptoms (PR:1.62; 95%CI 1.26­2.10) were some factors associated with higher IgG seroprevalence. Discussion: In Bucaramanga, SARS-CoV-2 seroprevalence among migrants was similar to the seroprevalences of migrants in Kuwait but lower than migrants in Paris and Singapore. Conclusions: The anti-SARS-CoV-2 seroprevalence among migrants with a vocation for permanence was similar to that reported among residents of Bucaramanga. Contact with suspected or confirmed COVID-19 cases and crowded conditions were some of the factors associated with seroprevalence.

Introdução: Existem poucos relatos que avaliam a soroprevalência contra SARS-CoV-2 na população migrante no mundo. Esses estudos ajudam a conhecer a exposição ao vírus nas populações para implementar ações que reduzam o impacto da infecção por SARS-CoV-2. Objetivo: Determinar a soroprevalência contra SARS CoV-2 em migrantes que pretendem permanecer em Bucaramanga e identificar fatores associados à infecção anterior por SARS-CoV-2. Materiais e Métodos: Estudo analítico transversal com amostragem consecutiva. Foram incluídos migrantes adultos em Bucaramanga durante fevereiro/2021. Foram realizados levantamentos e imunoensaios de quimioluminescência para IgM e IgG contra SARS-CoV-2 no soro. As razões de prevalência (RP) foram calculadas com regressão log-binomial. Resultados: foram incluídos 462 participantes. A soroprevalência de IgM foi de 11,7% (IC 95% 9,1-14,9), de IgG foi de 32,9% (IC 95% 28,8-37,3) e de IgM ou IgG foi de 36,1% (IC95% 31,9-40,6). Exposição a um caso confirmado (RP: 1,54; IC 95% 1,04-2,29) ou caso suspeito (RP: 1,56; IC 95% 1,13-2,16) de COVID-19, seis ou mais coabitantes (RP: 1,52; IC 95% 1,05 -2,20), permanência na Colômbia ≥2 anos (RP: 1,43; IC 95% 1,11-1,92) e presença de sintomas (RP: 1,62; IC95%1,26 - 2,10) foram associados a maior soroprevalência de IgG. Discussão: Em Bucaramanga, a soroprevalência em migrantes foi semelhante à de migrantes no Kuwait, mas menor do que em Paris e Cingapura. Conclusão: Em migrantes com vocação de permanência, a soroprevalência contra SARS-CoV-2 foi semelhante à relatada em residentes de Bucaramanga. O contato com casos suspeitos/confirmados de COVID-19 e as condições de superlotação foram alguns dos fatores associados à soroprevalência.

Chikungunya, Zika and Dengue seroprevalence rates among pregnant women in a hospital of southeastern Brazil / Soroprevalência de chikungunya, zika e dengue em gestantes de um hospital do sudeste do Brasil / Seroprevalencia de chikungunya, zika y dengue en mujeres embarazadas en un hospital del sureste de Brasil

Background and objectives: For decades, dengue outbreaks have been affecting vast territories of the Americas. In 2010's decade, Chikungunya and Zika virus (CHIKV and ZIKV) emerged as new arboviruses in the region. While several seroprevalence rates have been reported for dengue virus (DENV) infection in Brazil, serological surveys for the latest are scarce. We aimed to evaluate the seroprevalence of CHIKV, ZIKV, and DENV infections in pregnant women at admission to a public maternity hospital of Nova Iguaçu, state of Rio de Janeiro. Methods: A simple questionnaire was applied, containing limited demographic, obstetric, and clinical data, alongside with blood collection. Different commercial test kits, based on enzyme-linked immunosorbent assay (ELISA), were used. Results: Among 349 pregnant women enrolled from July to December 2017, there was a 28.4% seroreactivity for CHIKV, 47.2% for ZIKV, and 88.8% for DENV. Conclusion: These findings reflect the high dengue endemicity scenario and suggest a significant reach of the recent outbreaks of ZIKV and CHIKV infections in the region.(AU)

Justificativas e objetivos: Há décadas, surtos de dengue afetam vastos territórios das Américas. Na década de 2010, os vírus Chikungunya e Zika (CHIKV e ZIKV) surgiram como arbovírus emergentes na região. Embora diversas taxas de soroprevalência tenham sido relatadas para a infecção pelo vírus da dengue (DENV) no Brasil, pesquisas sorológicas para chikungunya e zika são escassas. Objetivou-se avaliar a soroprevalência das infecções por CHIKV, ZIKV e DENV em gestantes admitidas em uma maternidade pública de Nova Iguaçu, estado do Rio de Janeiro. Métodos: Foi aplicado um questionário simples, contendo dados demográficos, obstétricos e clínicos limitados, sendo realizada coleta de sangue na mesma visita. Diferentes kits de teste comerciais, baseados em ensaio imunoenzimático (ELISA), foram utilizados. Resultados: De 349 gestantes recrutadas de julho a dezembro de 2017, houve sororreatividade de 28,4% para CHIKV, 47,2% para ZIKV e 88,8% para DENV. Conclusão: Esses achados refletem o cenário de alta endemicidade da dengue e sugerem um alcance significativo dos surtos recentes causados por ZIKV e CHIKV na região.(AU)

Justificación y objetivos: Durante décadas, los brotes de dengue han afectado a vastos territorios de las Américas. En la década de 2010, los virus Chikungunya y Zika (CHIKV y ZIKV) surgieron como arbovirus emergentes en la región. Aunque se han reportadas varias tasas de seroprevalencia para la infección por el virus del dengue (DENV) en Brasil, la investigación serológica para el chikungunya y el Zika es escasa. Este estudio tuvo como objetivo evaluar la seroprevalencia de infecciones por CHIKV, ZIKV y DENV en mujeres embarazadas ingresadas en una maternidad pública en Nova Iguaçu, estado de Rio de Janeiro. Métodos: Se aplicó un sencillo cuestionario, que contenía datos demográficos, obstétricos y clínicos limitados, y se extrajo sangre en la misma visita. Se utilizaron diferentes kits de prueba comerciales basados en el ensayo inmunoabsorbente ligado a enzimas (ELISA). Resultados: De 349 mujeres embarazadas reclutadas de julio a diciembre de 2017, hubo serorreactividad de 28,4% para CHIKV, 47,2% para ZIKV y 88,8% para DENV. Conclusión: Estos hallazgos reflejan el escenario de alta endemicidad para el dengue y sugieren una variedad significativa de brotes recientes causados por ZIKV y CHIKV en la región.(AU)

Hepatitis A and E among immigrants and refugees in Central Brazil

ABSTRACT OBJECTIVE To estimate the prevalence of hepatitis A virus (HAV) and hepatitis E virus (HEV) among immigrants and refugees in Goiás, Central Brazil. METHODS Overall, 355 individuals were interviewed, and blood samples were tested for anti-HAV and anti-HEV IgG. Anti-HEV-positive samples were similarly tested for HEV RNA. RESULTS All participants were from Latin American countries, most of whom, young adult males. The overall anti-HAV IgG prevalence was 87.4% (95%CI: 83.5-90.4), of whom 94.9%, 75.6%, and 60% were from Haiti, Venezuela, and other Latin American countries, respectively (p < 0.001). Age above 19 years and more than 36 months residing in Brazil were associated with a higher prevalence of previous HAV and HEV infection, respectively. Of the children eligible for HAV vaccination according to the National Immunization Program, only eight (44%) had been vaccinated. The overall anti-HEV IgG prevalence was 6.5% (95%CI: 4.4-9.5). All anti-HEV IgG-positive individuals were Haitians, including a child born in Brazil. HEV RNA was detected in two of the anti-HEV IgG-positive samples. CONCLUSION The survey detected a high prevalence of anti-HAV and anti-HEV IgG among immigrants and refugees, and active HEV infection among some Haitian participants. Prevention measures are urgently required to interrupt enteric virus transmission in this emergent and vulnerable population.

Kashmiri refugees at the verge of hepatitis B and C epidemic in the State of Azad Jammu and Kashmir, Pakistan

ABSTRACT OBJECTIVE To determine the seroprevalence of hepatitis B and C among immigrants residing refugee camps in Muzaffarabad, Azad Kashmir, Pakistan, and to identify possible risk factors for hepatitis B virus (HBV) and hepatitis C virus (HCV) transmission. METHODS Around 1,225 individuals inhabiting Muzaffarabad refugee camps, participated in the study. A qualitative Immuno-Chromatographic Technique was used for initial screening and PCR test was used for detection of HBV and HCV in participants. The major risk factors for HBV and HCV transmission were assessed using a questionnaire approach. RESULTS Around 86 (7.0%) individuals were observed for hepatitis B surface antigen (HBsAg) presence, and 215 (17.5%) individuals were found positive for Anti-HCV. Only 32 (2.6%) individuals were confirmed for HBV DNA and 126 (10.3%) individuals were positive for HCV RNA after PCR. Demographically, both HBsAg and Anti-HCV were found more prevalent in female (4.4% HBsAg and 10.8% Anti-HCV) population as compared to male (2.6% HBsAg and 6.7% Anti-HCV) population. Surprisingly, the HBsAg (23.5%) and Anti-HCV (41.1%) appeared to be more frequent in the age group 62-75 years. Previous history of hepatitis in the family (p < 0.0001), blood transfusion (p = 0.0197) dental treatment (p < 0.0001) and tattooing or piercing on any part of the body (p = 0.0028) were assessed as significant risk factors in HBV and HCV transmission. CONCLUSIONS Presence of 7.0% HBsAg and 17.5% Anti-HCV in a small fragment of the migrant population cannot be overlooked. Lack of awareness among people and negligence of health department could escalate the situation.

Seroprevalencia de infección reciente por dengue en una zona de riesgo

RESUMEN Introducción: El dengue se ha convertido en una de las enfermedades de mayor impacto epidemiológico, social y económico a nivel mundial. Objetivo: Estimar la prevalencia de la infección reciente por dengue en una zona de riesgo. Métodos: Estudio de corte transversal realizado en la Isla de la Juventud, Cuba, en el período comprendido entre julio y septiembre de 2021. Para el estudio epidemiológico se escogieron 12 manzanas, 57 viviendas y 2 participantes por cada una. Para la determinación serológica se utilizó el diagnosticador Umelisa Dengue IgM plus. Se calcularon frecuencias absolutas y relativas, prueba de chi-cuadrada e intervalos de confianza. Se mapificó análisis de focalidad en el radio de acción, así como los casos seropositivos. Se estimó la densidad demográfica y se tuvieron en cuenta variables de temperatura y precipitaciones. Resultados: Se estudiaron 106 individuos y se detectó una seroprevalencia de 10,3 % (IC95%: 5,29-17,81). El sexo femenino tuvo mayor prevalencia (14,7 %) (IC95%: 7,28-25,39); así como los mayores de 60 años 11,9 % (IC95%: 3,98-25,63). Se encontró relación significativa entre la seroprevalencia y el sexo. Se geolocalizaron 11 casos seropositivos donde la presencia del vector quedó documentada. Las temperaturas medias resultaron similares en los tres meses abordados, mientras que las precipitaciones fueron superiores en el mes de agosto. La focalidad marcó una tendencia al incremento, con su mayor pico en el mes de septiembre. Conclusiones: La seroprevalencia de la infección por dengue en la Isla de la Juventud, en el período analizado es alta y se asocia con el sexo.

ABSTRACT Introduction: Dengue has become one of the diseases with the greatest epidemiological, social and financial impact worldwide. Objective: To estimate the prevalence of recent dengue infection in a risk area. Methods: A cross-sectional study conducted between July and September 2021 on the Isle of Youth, Cuba. 12 blocks, 57 houses and 2 residents per house were selected for the epidemiological study. The UMELISA Dengue IgM Plus Kit was used for the serological determination. Absolute and relative frequencies, chi-square test and confidence interval were calculated. The seropositive cases and the analysis of the positive breeding sites in the radius of action were mapped. Population density was estimated and temperature and rainfall variables were taken into account. Results: A total of 106 individuals were studied and a seroprevalence of 10.3% (95% CI, 5.29-17.81) was found. Females had a higher prevalence rate (14.7%) (95% CI, 7.28-25.39), as well as individuals aged over 60 years (11.9%) (95% CI, 3.98-25.63). A significant association was identified between seroprevalence and sex. Eleven positive cases were mapped and the presence of the vector was documented. Average temperature was similar over the three months under study, while rainfall was higher in August. Positive breeding sites tended to increase with a higher peak in September. Conclusions: Seroprevalence of dengue infection on the Isle of Youth in the period under study is high and is associated with the sex.

Soroprevalência de marcadores de triagem sorológica para doenças transmissíveis por transfusão em doadores de sangue em Sergipe, Brasil / Seroprevalence of serological screening markers for transfusion-transmitted diseases in blood donors in Sergipe, Brazil / Seroprevalencia de marcadores de cribado serológico para enfermedades transmisibles por transfusión en donantes de sangre en Sergipe, Brasil

A transfusão de sangue é um procedimento comum nos serviços de saúde, embora não seja isento de riscos. O descarte sorológico e a análise do perfil do doador fornecem informações essenciais para a segurança da transfusão. Este artigo avalia a prevalência e a tendência de descarte das bolsas de sangue por positividade sorológica para doenças transmissíveis por transfusão do hemocentro de Sergipe. Trata-se de um estudo observacional, relativo às doações realizadas entre janeiro de 2007 e dezembro de 2018. Das 308.953 doações, 16.828 (5,45%) foram descartadas devido à positividade em alguma sorologia de triagem. Verificou-se uma tendência de diminuição do descarte de bolsas de sangue nas sorologias testadas. As sorologias responsáveis pelo descarte foram: anti-HBc (2,09%), sífilis (1,49%), anti-HIV (0,82%), HBsAg (0,62%), anti-HCV (0,52%), anti-HTLV-1/2 (0,23%) e Chagas (0,15%). Com relação ao perfil do doador, houve maior descarte de doadores homens, de reposição e de faixas etárias avançadas. Neste estudo foi encontrada uma alta prevalência de descarte, embora com tendência decrescente para todas as sorologias, exceto sífilis, que permaneceu estacionária no período. Os resultados reforçam a necessidade dos processos de triagem sorológica para garantir a segurança transfusional, tendo em vista que essas doenças ainda são frequentes na população. Evidencia-se a importância da realização de campanhas educativas, de testagem e tratamento para as principais infecções de risco transfusional para que diminua a taxa de descarte de bolsas de sangue e melhore a qualidade transfusional.

Although a common health care procedure, blood transfusion is not risk-free. Serological disposal and donor profile analysis provide key information for transfusion safety. This study evaluates the prevalence and tendency of discarding blood bags due to serological positivity for transfusion-transmitted diseases at a blood center in Sergipe, Brazil. An observational study was conducted on donations made between January 2007 and December 2018. Of the 308,953 donations received, 16,828 (5.45%) were discarded due to positive screening serology, with a decrease trend in discard for the serologies tested. Anti-HBc (2.09%), syphilis (1.49%), anti-HIV (0.82%), HBsAg (0.62%), anti-HCV (0.52 %), anti-HTLV-1/2 (0.23%) and Chagas (0.15%) were the serologies responsible for disposal. As for donor profile, greater discard was observed for men, replacement and advanced age donors. Results showed a high prevalence of discard, but with a decreasing trend for all serologies excepting syphilis, which remained stationary in the period. They reinforce the importance of serological screening processes for ensuring transfusion safety, as these diseases are still common among the population. Carrying out educational, testing and treatment campaigns for the main transfusion risk infections is essential to reduce blood bag disposal rate and improve transfusion quality.

La transfusión de sangre es un procedimiento común en los servicios de salud, aunque no está libre de riesgos. La eliminación serológica y el análisis del perfil del donante proporcionan información esencial para la seguridad de las transfusiones. Este estudio tiene como objetivo evaluar la prevalencia y tendencia del descarte de bolsas de sangre por positividad serológica para enfermedades transmisibles por transfusión en el hemocentro de Sergipe (Brasil). Se trata de un estudio observacional, relacionado con las donaciones realizadas entre enero de 2007 y diciembre de 2018. De las 308.953 donaciones, 16.828 (5,45%) se descartaron por positividad en alguna serología de cribado. Hubo una tendencia a disminuir el descarte de bolsas de sangre en las serologías probadas. Las serologías responsables de la eliminación fueron: anti-HBc (2,09%), sífilis (1,49%), anti-VIH (0,82%), HBsAg (0,62%), anti-HCV (0,52%), anti-HTLV-1/2 (0,23%) y Chagas (0,15%). En cuanto al perfil del donante, hubo un mayor descarte en los donantes masculinos, de reemplazo y en edad avanzada. En el estudio se constató una alta prevalencia de descarte, aunque con tendencia decreciente para todas las serologías, excepto para sífilis, que se mantuvo estacionaria en el período. Los resultados refuerzan la necesidad de procesos de cribado serológico para garantizar la seguridad transfusional, dado que estas enfermedades aún son comunes en la población. Se resalta la importancia de realizar campañas de educación, testeo y tratamiento de las principales infecciones de riesgo transfusional para reducir la tasa de eliminación de bolsas de sangre y mejorar la calidad transfusional.

Seroprevalencia de SARS-CoV-2 en adultos y adultos mayores en México y su asociación con enfermedades crónicas. Ensanut 2020 Covid-19 / Seroprevalence of SARS-CoV-2 in adults and older adults in Mexico and its association with chronic diseases. Ensanut 2020 Covid-19

Resumen: Objetivo: Analizar la asociación entre seropositividad a SARS-CoV-2 y enfermedades crónicas en adultos y adultos mayores mexicanos. Material y métodos: Se utilizó la Encuesta Nacional de Salud y Nutrición 2020 sobre Covid-19 (Ensanut 2020 Covid-19) para evaluar la asociación de seropositividad a SARS-CoV-2 con hipertensión arterial sistémica, diabetes tipo 2, índice de masa corporal, LDL-c elevado, HDL-c bajo, colesterol total elevado e hipertrigliceridemia. Resultados: Se observó una mayor seropositividad en personas con mayor índice de masa corporal. La seroprevalencia fue 25% mayor entre los adultos que presentaban obesidad en comparación con aquellos de peso normal en modelos ajustados (RP: 1.25 IC95%: 1.08,1.46). No se observó asociación entre seropositividad y otras enfermedades crónicas en adultos o adultos mayores. Conclusiones: Las personas con obesidad podrían tener una mayor susceptibilidad a la infección por SARS-CoV-2. Este hallazgo debe ser confirmado con estudios longitudinales. No se encontró evidencia de asociación para otras enfermedades.

Abstract: Objective: To analyze the association between seropositivity to SARS-CoV-2 and chronic diseases in Mexican adults and older adults. Materials and methods: We used the 2020 National Health and Nutrition Survey on Covid-19 to evaluate the association of seropositivity to SARS-CoV-2 with high blood pressure, type 2 diabetes, body mass index, elevated LDL-c, low HDL-c, high total cholesterol, and hypertriglyceridemia. Results: We observed a higher seropositivity at higher body mass index levels. In adjusted models, seroprevalence was 25% higher among adults with obesity compared to those of normal weight (PR: 1.25 95%CI: 1.08,1.46). We did not observe any association between seropositivity and other chronic diseases in adults or older adults. Conclusions: Adults with obesity could be at increased susceptibility of SARS-CoV2 infection. This observation needs to be confirmed through longitudinal studies. We did not find evidence of an association with other chronic diseases.

Hábitos alimentarios y de higiene asociados a la seroprevalencia de Helicobacter pylori en estudiantes universitarios peruanos / Dietary and hygiene habits associated with the Helicobacter pylori seroprevalence in Peruvian university students / Hábitos alimentares e de higiene associados à soroprevalência do Helicobacter pylori em estudantes universitários peruanos

RESUMEN Introducción: La infección por Helicobacter pylori es cada vez más frecuente en los jóvenes peruanos e incrementa su riesgo de padecer neoplasias gástricas. Objetivo: Determinar los hábitos alimentarios y de higiene asociados a la seroprevalencia de infección por Helicobacter pylori en estudiantes universitarios del departamento de Cajamarca, Perú, durante los meses de septiembre a octubre de 2019. Método: Estudio observacional, transversal, prospectivo con un diseño no experimental. La población estuvo conformada por 367 estudiantes de la carrera profesional de Tecnología Médica. El tamaño de la muestra fue de 188 estudiantes de ambos géneros. Se detectaron anticuerpos IgG frente a Helicobacter pylori en suero, mediante el método de inmunocromatografía. Los hábitos alimentarios y de higiene se recopilaron utilizando una encuesta estructurada. Resultados: El 51,1 % de estudiantes presentó anticuerpos IgG frente a Helicobacter pylori. El 31,38 % de los estudiantes que consumía "a veces" alimentos elaborados en la calle resultaron seropositivos a Helicobacter pylori. Aquellos estudiantes que manifestaron lavarse las manos "a veces" (29,79 %) y "siempre" (21,28 %) antes de ingerir los alimentos presentaron anticuerpos IgG contra la bacteria. Además, los estudiantes seropositivos frente a Helicobacter pylori lavaban sus frutas y verduras con el agua del grifo (43,62 %) y consumían agua de grifo no tratada (29,79 %). Conclusión: El consumo de alimentos preparados en la calle, lavado de manos antes de consumir alimentos, tipo de agua para consumo y lavado de frutas y verduras antes de ingerirlas son hábitos alimentarios y de higiene asociados a la seroprevalencia de Helicobacter pylori.

ABSTRACT Introduction: Helicobacter pylori infection is becoming more frequent in the young population of Peru and at the same time increases the risk of gastric neoplasms. Objective: To identify the dietary and higiene habits associated with the seroprevalence of Helicobacter pylori infection in university students at the Cajamarca Department. Assesed period from September throughout October 2019. Method: An observational, cross-sectional, prospective study with a non-experimental design was carried out. A population of 367 students on Medical technology career were involved and 188 of them, in both sex, were selected as trial. It was detected, using the immunochromatography method in serum assay, IgG antibodies against Helicobacter pylori. Dietary and hygiene habits were collected using a well-structed enquiry. Results: It was identified IgG antibodies against Helicobacter pylori infection in 51.1% of students. The 31.38% of those who, not frequently, had consumed food prepared outdoors were seropositive for Helicobacter pylori. Those students who revealed wash their hands, not frequently (29.79%) and frequently (21.28%) before eating, produced antibodies against this bacterial infection. In addition, Helicobacter pylori seropositive students washed their fruits and vegetables with obtained water from the tap (43.62%) and consumed untreated water fom the tap too (29.79%). Conclusions: Food intake outdoors, wash of hands, fruits and vegetables before eating, and the quality of water to be consumption are dietary and hygiene habits associated with the Helicobacter pylori seroprevalence.

RESUMO Introdução: A infecção por Helicobacter pylori é cada vez mais comum em jovens peruanos e aumenta o risco de neoplasias gástricas. Objetivo: Determinar os hábitos alimentares e de higiene associados à soroprevalência da infecção por Helicobacter pylori em universitários do departamento de Cajamarca, Peru, durante os meses de setembro a outubro de 2019. Método: Estudo observacional, transversal, prospectivo com um não experimental. A população foi composta por 367 alunos da carreira de Tecnologia Médica. O tamanho da amostra foi de 188 alunos de ambos os sexos. Os anticorpos IgG contra Helicobacter pylori foram detectados no soro pelo método de imunocromatografia. Os hábitos alimentares e de higiene foram coletados por meio de questionário estruturado. Resultados: 51,1% dos alunos apresentaram anticorpos IgG contra Helicobacter pylori. 31,38% dos alunos que comeram "às vezes" alimentos preparados na rua eram soropositivos para Helicobacter pylori. Os alunos que relataram lavar as mãos "às vezes" (29,79%) e "sempre" (21,28%) antes de comer apresentaram anticorpos IgG contra a bactéria. Além disso, os alunos soropositivos para Helicobacter pylori lavavam frutas e vegetais com água da torneira (43,62%) e consumiam água da torneira não tratada (29,79%). Conclusão: O consumo de alimentos preparados na rua, a lavagem das mãos antes de consumir os alimentos, o tipo de água para consumo e a lavagem de frutas e verduras antes de ingeri-los são hábitos alimentares e de higiene associados à soroprevalência do Helicobacter pylori.

Severe acute respiratory syndrome Coronavirus 2. Seroepidemiology study in Argentinian slum / Estudio seroepidemiológico de enfermedad por Coronavirus 2019 en un barrio de Argentina

Abstract Most countries in Latin America have already reported thousands of confirmed cases and vulnerable populations are the most affected by the coronavirus disease 2019 (COVID-19) pandemic. Preventive measures such as hygiene, social distancing, and isolation, essential to stop the spread of coronavirus, are difficult to accomplish for vulnerable populations due to their living conditions. Seroepidemiological surveys are assets to measure the transmission for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Until July 1st, the incidence rate of SARS-CoV-2 infection in Barrio Padre Mugica, one of the largest slums in Buenos Aires City, was 5.9%. This study aimed to establish the prevalence of SARS-CoV-2 antibodies immunoglobulin G (IgG) immediately after the outbreak, and to identify neighbourhood, household and individual factors associated with seroconversion. The prevalence based on IgG was 53.4% (95% CI 52.8% to 54.1%). For each polymerase chain reaction (RT-qPCR) confirmed case, nine people tested IgG positive, indicating a high rate of undetected (probably asymptomatic) infections. Hence, the high rate of undiagnosed people suggests that clinical criteria and epidemiological nexus should be considered. The high seroprevalence observed in the context of an intense epidemic in a vulnerable area might serve as a reference to other countries. This study contributes to future decision making by understanding population immunity against SARS-CoV2 and its relation to living conditions and foccus that comprehensive biosocial, household-level interventions are needed.

Resumen Muchos países de América Latina han informado miles de casos confirmados y las poblaciones vulnerables son las más afectadas por la pandemia de la enfermedad por coronavirus 2019 (COVID-19). Las medidas preventivas como la higiene, el distanciamiento social y el aislamiento, fundamentales para frenar la propagación del coronavirus, son difíciles de lograr en estas poblaciones debido a sus condiciones de vida. Los estudios seroepidemiológicos son de gran utilidad para medir la transmisión del síndrome respiratorio agudo severo coronavirus 2 (SARS-CoV-2). Hasta el 1 de julio, la tasa de incidencia de la infección por SARS-CoV-2 en el Barrio Padre Mugica, uno de los barrios marginales más grandes de la ciudad de Buenos Aires, era del 5.9%. Este estudio tuvo como objetivo estimar la prevalencia de anticuerpos inmunoglobulina G (IgG) para SARS-CoV-2 inmediatamente después del brote, e identificar factores del barrio, hogar e individuales asociados con la seroconversión. La prevalencia basada en IgG fue del 53.4% (IC del 95%: 52.8% a 54.1%). Para cada caso confirmado por reacción en cadena de la polimerasa (RT-qPCR), nueve personas dieron positivo en IgG, lo que indica una alta tasa de infecciones no detectadas y probablemente asintomáticas. La alta tasa de personas no diagnosticadas sugiere que se deben considerar los criterios clínicos y el nexo epidemiológico. La alta seroprevalencia observada en el contexto de una intensa epidemia en una zona vulnerable podría servir de referencia a otros países. Este estudio contribuye a la toma de decisiones futuras al comprender la inmunidad de la población contra el SARS-CoV2 en su relación con las condiciones de vida y por su enfoque en la necesidad de intervenciones integrales a nivel del hogar.

Seroepidemiologicalmonitoring of SARS-CoV-2 IgG in main railway stations in the city of Buenos Aires, Argentina / Monitoreo seroepidemiológico de igg contra el sars-cov-2 en estaciones ferroviarias cabeceras de la ciudad autónoma de buenos aires, argentina

RESUMEN INTRODUCCIÓN : Los estudios de seroprevalencia permiten monitorear la circulación del SARS-CoV-2 y dan información para evaluar medidas sanitarias. El objetivo fue conocer la proporción y evolución de la seropositividad en puntos de gran circulación de la Ciudad Autónoma de Buenos Aires (CABA) y las características clínico-epidemiológicas de los seropositivos, de abril a octubre de 2020. MÉTODOS : Se realizó un estudio descriptivo transversal de seis rondas de testeos rápidos serológicos y una encuesta de datos epidemiológicos. Se realizó un muestreo por conveniencia en tres estaciones ferroviarias cabeceras de CABA consideradas puntos de alto tránsito bidireccional del Área Metropolitana de Buenos Aires. RESULTADOS : Participaron 7339 personas. La proporción de seropositivos fue 0,6% (IC95%: 0,2-0,9) en la primera ronda y aumentó a 5,6% en la última (IC95%: 4,3-7). Al inicio aumentó la seropositividad en residentes de CABA y de la zona sur de la Región Metropolitana de Buenos Aires. El antecedente de haber presentado síntomas y el de contacto con personas con COVID-19 fueron las únicas variables relacionadas con el resultado de inmunoglobulina G positivo (p <0,05). El 56,1% (n = 97) de los seropositivos no tuvo síntomas. El 78,4% (n = 134) no fue diagnosticado en la etapa aguda. DISCUSIÓN : La seropositividad fue en ascenso en cada ronda, en coincidencia con la situación epidemiológica de la zona de residencia. Las características epidemiológicas como la proporción de seropositivos sin antecedentes de síntomas, reafirman la importancia de las medidas sanitarias poblacionales.

ABSTRACT INTRODUCTION : Seroprevalence studies allow monitoring the circulation of SARS-CoV-2, providing information to evalúate public health measures. The aim of this study was to determine the proportion and evolution of seropositivity in high circulation points in the Ciudad Autónoma de Buenos Aires (CABA) and clinical and epidemiological characteristics of seropositive individuals from April to October 2020. METHODS : A descriptive cross-sectional study was conducted during six rounds, using rapid serological testing together with an epidemiological data survey. A convenience sample was selected in three CABA railway stations considered as high bi-directional traffic points in the Buenos Aires Metropolitan Area (AMBA). RESULTS : 7,339 people participated. The seropositive proportion was 0.6% (95%CI: 0.2-0.9) in the first round, and rose to 5.6% in the last one (95%CI: 4.3-7). Initially, seropositivity increased in CABA residents and those living in the southern part of the Buenos Aires Metropolitan Region. Having presented symptoms and history of contact with COVID-19 cases were the only variables found to be related to positive IgG results (p<0.05). Among seropositive participantes, 56.1% (n=97) had no symptoms and 78.4% (n=134) didn't receive a COVID-19 diagnosis in the acute stage. DISCUSSION : Seropositivity increased between rounds, according to the epidemiological situation in the area of residence. Epidemiological characteristics, such as the proportion of seropositive individuals with no history of symptoms, reaffirm the importance of public health and social measures.

Population-level seropositivity trend for SARS-Cov-2 in Rio Grande do Sul, Brazil

ABSTRACT OBJECTIVE To describe the evolution of seropositivity in the State of Rio Grande do Sul, Brazil, through 10 consecutive surveys conducted between April 2020 and April 2021. METHODS Nine cities covering all regions of the State were studied, 500 households in each city. One resident in each household was randomly selected for testing. In survey rounds 1-8 we used the rapid WONDFO SARS-CoV-2 Antibody Test (Wondfo Biotech Co., Guangzhou, China). In rounds 9-10, we used a direct ELISA test that identifies IgG to the viral S protein (S-UFRJ). In terms of social distancing, individuals were asked three questions, from which we generated an exposure score using principal components analysis. RESULTS Antibody prevalence in early April 2020 was 0.07%, increasing to 10.0% in February 2021, and to 18.2% in April 2021. In round 10, self-reported whites showed the lowest seroprevalence (17.3%), while indigenous individuals presented the highest (44.4%). Seropositivity increased by 40% when comparing the most with the least exposed. CONCLUSIONS The proportion of the population already infected by SARS-Cov-2 in the state is still far from any perspective of herd immunity and the infection affects population groups in very different levels.

Prevalence of symptoms of COVID-19 in the state of Rio Grande do Sul: results of a population-based study with 18,000 participants / Prevalência de sintomas característicos de covid-19 no Rio Grande do Sul: resultados de um estudo de base populacional com 18 mil participantes

ABSTRACT OBJECTIVE To evaluate the prevalence of reports of symptoms of COVID-19 among individuals with and without antibodies and identify those with greater capability to predict the presence of antibodies against SARS-CoV-2. METHODS The study uses data collected in phases 5 to 8 of Epicovid-19-RS. The presence of antibodies against SARS-CoV-2 was evaluated by a rapid test. The occurrence of cough, fever, palpitations, sore throat, difficulty breathing, changes in taste and smell, vomiting, diarrhea, body pain, shaking, and headache since March 2020 was also evaluated. Then, the capability to predict the evaluated symptoms concerning the presence of antibodies was calculated. RESULTS A total of 18,000 individuals were interviewed and 181 had antibodies against COVID-19 in phases 5 to 8. The proportion of asymptomatic individuals was 19.9% among participants with antibodies and 49.7% among those without antibodies. All symptoms were reported more frequently by individuals with antibodies. The division of the prevalence of symptoms among individuals with antibodies by the prevalence among individuals without antibodies showed the following prevalence ratios: for changes in smell or taste (9.1), fever (4.2), tremors (3.9), breathing difficulty (3.2) and cough (2.8 times). Anosmia and fever were the symptoms with a greater capability to predict the presence of antibodies. CONCLUSION The prevalence of symptoms was higher among individuals with antibodies against SARS-CoV-2. The proportion of asymptomatic individuals was low. Altered smell or taste and fever were the symptoms that most predict the presence of antibodies. These results can help to identify probable cases, contributing to the clinical diagnosis and screening of patients for testing and isolation guidance in positive cases, especially in scenarios of the scarcity of diagnostic COVID-19 tests.

RESUMO OBJETIVO Avaliar prevalência de relato de sintomas característicos de covid-19 entre indivíduos com e sem anticorpos e identificar aqueles com maior capacidade de predição da presença de anticorpos contra o SARS-CoV-2. MÉTODOS O presente estudo usa dados coletados nas fases de 5 a 8 do Epicovid-19-RS. A presença de anticorpos contra o SARS-CoV-2 foi avaliada por um teste rápido. Avaliou-se também a ocorrência dos sintomas tosse, febre, palpitações, dor de garganta, dificuldade para respirar, alterações no paladar e olfato, vômito, diarreia, dor no corpo, tremedeira e dor de cabeça, desde março de 2020. Então, calculou-se a capacidade de predição dos sintomas avaliados em relação a presença de anticorpos. RESULTADOS Nas fases de 5 a 8, 18 mil indivíduos foram entrevistados e 181 apresentaram anticorpos contra covid-19. A proporção de indivíduos assintomáticos foi de 19,9% entre participantes com anticorpos e 49,7% entre aqueles sem anticorpos. Todos os sintomas foram relatados com maior frequência por indivíduos com presença de anticorpos. A divisão da prevalência de sintomas entre indivíduos com anticorpos pela prevalência entre indivíduos sem anticorpos evidenciou as seguintes razões de prevalência: para alterações de olfato ou paladar (9,1), febre (4,2), tremedeira (3,9), dificuldade respiratória (3,2) e tosse (2,8 vezes). Anosmia e febre foram os sintomas com maior capacidade de predizer a presença de anticorpos. CONCLUSÃO A prevalência de sintomas foi maior entre indivíduos com anticorpos contra SARS-CoV-2. A proporção de indivíduos assintomáticos foi baixa. Alteração de olfato ou paladar e febre foram os sintomas que mais predizem a presença de anticorpos. Esses resultados podem auxiliar a identificação de casos prováveis, contribuindo para o diagnóstico clínico e triagem de pacientes para testagem e orientação de isolamento em casos positivos, especialmente em cenários de escassez de testes diagnósticos de covid-19.

Seroprevalence and risk factors of Chagas disease in a rural population of the Quixeré municipality, Ceará, Brazil

Abstract INTRODUCTION: This study estimated the seroprevalence and risk factors of Chagas disease (CD) in a population of the Quixeré municipality, Ceará. METHODS: We conducted serological methods to detect the Trypanosoma cruzi infection. The other variables were evaluated by a standardized questionnaire. RESULTS: The estimated prevalence of CD was 3.7%. Male sex, age >40 years, being farmers, low education level, origin from rural areas, and being born in Quixeré were significantly associated with infection. CONCLUSION: CD persists in this rural population of Northeast Brazil. Poverty, low education, and limited information regarding CD are critical issues that need to be addressed.