Respiratory Syncytial Virus (RSV) is a common cause of acute lower respiratory tract infection (LRTI) in pediatrics. The lymphocyte-to-C-reactive protein ratio (LCR) has been studied as a predictor of inflammation, sepsis, and severity in viral respiratory infections. Objectives: To estimate the LCR in hospitalized infants with RSV-associated acute LRTI and assess its ability to identify disease severity. Patients and Method: A cross-sectional study including infants hospitalized with a diagnosis of RSV-associated acute LRTI over 12 months. Absolute lymphocyte count (cells/mm3), C-reactive protein (CRP) level (mg/L), and the Argentine Respiratory Distress Assessment Scale (EDRAR) score at admission were recorded. The LCR was calculated and categorized into two groups: LCR < 100 and >= 100, and its relationship with EDRAR was analyzed. Results: A total of 209 patients were included, with a mean age of 7.4 +/- 6.3 months. According to the EDRAR, only 6.7% (n = 14) were classified as severe. The median LCR was 305.7 (IQR 109.3-1201.5), with no significant difference between severe and non-severe patients (p = 0.9). In 23.4% of patients, LCR was < 100, with a sensitivity of 70.3% (95% CI: 63.2-76.4) and specificity of 28.57% (95% CI: 9.58-58) for predicting severity. Conclusion: In infants hospitalized with RSV-associated acute LRTI, the LCR was not useful in predicting disease severity.

Introduction. The medical residency system is a professional training program. In Argentina, the Unified Exam (UE) centralizes admission to most residencies. In 2025, a five-point bonus was added for graduates of Argentine universities to compensate for differences observed in graduation averages compared to those of foreign graduates. Objective. To analyze the average grade point average, UE score, and differences according to foreign status. Population and methods. Cross-sectional study. It included 470 applicants for pediatric residency; 32.8% were foreign nationals, and 28.3% were graduates of foreign universities. Results. Foreign university graduates had higher academic averages (7.8 vs. 7.4; p <0.001) but lower UE performance (58.8 vs. 72.6; p <0.001). The correlation between career average and UE score was significant (R-2 = 0.25). Conclusion. These results provide evidence for evaluating the impact and relevance of the applied bonus to ensure equity in access to residencies.

BACKGROUND:Argentina pioneered the implementation of maternal immunization (MI) with RSVpreF to prevent RSV hospitalizations in infants. This study aims to assess the residual burden of RSV-related hospitalizations in infants under 12 months during Argentina's first season of MI. METHODS:This multicentre, retrospective cohort study utilized the RIMA network across five tertiary hospitals in the Metropolitan Area of Buenos Aires. We analysed RSV-related hospitalizations in infants <12 months old during the first post-MI season (2024) and compared them with historical data (2018-2023). The primary objective was to characterize the "protection gap" among hospitalized infants. FINDINGS:Overall, 10,860 infants aged <12 months were hospitalized with ALRTI during the study; 3967 (36.29%) were RSV-positive. During the first vaccination season, 91.73% (477/520) of RSV-hospitalized infants were born to unvaccinated mothers. The primary protection gap was temporal: 43.18% (133/308) of infants under 6 months hospitalized during 2024 were born before the vaccination campaign started. Severe RSV disease remained prevalent, with 131/148 infants (88.52%) requiring PICU admission. INTERPRETATIONS:While maternal immunization is a landmark intervention, a substantial residual burden of severe RSV remains in Argentina. This burden is driven by infants born outside the vaccination window and high-risk preterm cohorts. To achieve comprehensive protection, coordinated strategies, including the integration of long-acting monoclonal antibodies alongside maternal vaccines, are necessary to close existing equity and protection gaps. FUNDING:This work was supported by SANOFI and AstraZeneca (RSV00105).

BackgroundMost children in Argentina received only the initial COVID-19 vaccine series, with presumed hybrid immunity after multiple Omicron waves. However, the durability of immune memory, particularly in immunocompromised (IC) children, remains poorly studied.MethodsA cohort of IC (n=45) and healthy children (HC, n=79) was assessed between 13 to 17 months after receiving two or three doses of BBIBP-CorV and/or BNT162b2. Plasma anti-spike IgG, neutralizing activity and antigen-specific CD4+ and CD8+ T cells against Wuhan and Omicron BA.5 variants were assessed.ResultsMost children remained seropositive after two vaccine doses, but compared with HC, IC exhibited lower neutralizing titers against both Wuhan and Omicron BA.5, particularly those vaccinated with BBIBP-CorV. Even after three vaccine doses, IC showed weaker neutralizing antibody response, CD8+ T cell responses and lower IFN-γ production compared with HC. Integrated analysis of neutralizing antibodies, memory CD4+, and CD8+ T cells revealed a weak immune memory among IC with an important compromise in memory CD8+ T cell responses.ConclusionsImmunity can last up to 17 months, but reduced effectiveness against new variants highlights the need for updated COVID-19 vaccines, especially for IC children. Additional efforts are essential to enhance vaccination coverage and protect this vulnerable population.

Introduction. In Pediatrics, communication involves children and their families. Students with the highest interaction with children can approach this subject with greater confidence. Objective. To assess the interaction with children of medical students in their daily lives and its correlation with confidence at the start of the Pediatrics course. Methods. A self-administered survey study of pediatric students of the School of Medicine of the Universidad de Buenos Aires inquired about the frequency of interaction with children under 12 years of age and confidence in this interaction. Results. A total of 286/450 responses were obtained. Only 27 students lived with children, and 14 were parents. Most had little interaction (1-2 times a year or less) with children (64% infants, 64.3% preschoolers, 54.6% schoolchildren). A positive correlation was found between interaction level and confidence (p < 0.01). Conclusion. Medical students have limited interaction with minors in their daily lives, which affects their confidence in taking a Pediatrics course.

Introduction. Acute lower respiratory infections (ALRI) due to respiratory syncytial virus (RSV) are a significant cause of disease. Most of them are treated outpatient without etiological investigation, making it difficult to estimate the disease burden. In 2020, an algorithm was developed to identify consultations for ALRI in electronic health records. We evaluated the algorithm's behavior in patients with RSV ALRI. Methods. The cross-sectional study included children under 5 years of age who consulted for ALRI with viral screening. The algorithm was applied to their health records, calculating diagnostic capacity to identify RSV ALRI. Results. We included 133 patients (age 4.9 ± 4.1 years). RSV was identified in 21.8%. The algorithm identified ALRI in 33.8% (95%CI: 26.3-42.2) and showed a limited ability to identify RSV infection (sensitivity: 55.2%, specificity: 72.1%). Conclusion. An algorithm for identifying ALRI consultations in electronic health records does not adequately distinguish those caused by RSV.

Background:Respiratory syncytial virus (RSV) is a major cause of hospitalizations and mortality in young infants worldwide. The RSVpreF maternal immunization (MI) was recently introduced in Argentina. Methods:This study assessed the impact of RSVpreF MI on RSV-related acute lower respiratory tract infections (ALRTI) hospitalizations through a hospital-based, multicentre, retrospective surveillance cohort study, and measured vaccine effectiveness (VE) using a nested test-negative case-control study. Data of hospitalized infants under 18 months of age was collected and analysed within seven years from three Argentine tertiary hospitals. VE analysis included ALRTI-hospitalized infants who were born between March 1 and November 9, 2024, were under 6 months of age when tested for RSV, and whose mothers were eligible for prenatal RSV immunization. Expected RSV-ALRTI hospitalizations were compared with observed cases using a Poisson model. We estimated the VE of RSVpreF MI against RSV-ALRTI hospitalizations, paediatric intensive care unit (PICU) admissions, and extended hospital stays by comparing these rates in vaccinated and unvaccinated under 3 and 6 months. Findings:A total of 3373 participants were included in the impact analysis, fromof whom 323 were born during the vaccination period and were eligible for the VE analysis. The VE of RSVpreF MI was 80·8% (95% CI: 62·8-90·5%), and 66·1% (95% CI 30·1-83·8) for infants under 3 and 6 months, respectively, adjusted for age, sex, comorbidities, and epidemiological weeks. VE for PICU admission was 87·2% (95% CI 52·6-97·0) and 88·6% (95% CI 62·3-97·1) for extended hospital stays in infants under 6 months. The vaccine reduced RSV-ALRTI hospitalizations in infants under 6 months by 33·6% (95% CI 29·5-37·2) in 2024 compared to expected cases from previous years. The number needed to immunize to prevent one RSV-related hospitalization was 83·9 (95% CI 65·9-185·4). Interpretation:RSVpreF MI significantly reduced RSV-ALRTI hospitalizations, averting one-third of such hospitalizations in infants under 6 months. These findings provide valuable evidence for policymakers and health authorities. Funding:Gates Foundation and Thrasher Research Fund.

INTRODUCTION:The rate of hospital readmission within 30 days of discharge is a quality indicator in health care. Paediatric patients with complex chronic conditions have high readmission rates. Failure in the transition between hospital and home care could explain this phenomenon. OBJECTIVES:To estimate the incidence rate of 30-day hospital readmission in paediatric patients with complex chronic conditions, estimate how many are potentially preventable and explore factors associated with readmission. MATERIALS AND METHOD:Cohort study including hospitalised patients with complex chronic conditions aged 1 month to 18 years. Patients with cancer or with congenital heart disease requiring surgical correction were excluded. The outcomes assessed were 30-day readmission rate and potentially preventable readmissions. We analysed sociodemographic, geographic, clinical and transition to home care characteristics as factors potentially associated with readmission. RESULTS:The study included 171 hospitalizations, and 28 patients were readmitted within 30 days (16.4%; 95% CI, 11.6%-22.7%). Of the 28 readmissions, 23 were potentially preventable (82.1%; 95% CI, 64.4%-92.1%). Respiratory disease was associated with a higher probability of readmission. There was no association between 30-day readmission and the characteristics of the transition to home care. CONCLUSIONS:The 30-day readmission rate in patients with complex chronic disease was 16.4%, and 82.1% of readmissions were potentially preventable. Respiratory disease was the only identified risk factor for 30-day readmission.

IntroducciónLa tasa de reingreso hospitalario a 30 días del alta es una medida de calidad de la atención médica. Los pacientes pediátricos con enfermedades crónicas complejas tienen altas tasas de reingreso. La falla en la transición entre el cuidado hospitalario y domiciliario podría explicar este fenómeno.ObjetivosEstimar la tasa de incidencia de reingreso hospitalario a 30 días en pacientes pediátricos con enfermedades crónicas complejas, estimar cuántos son potencialmente prevenibles y explorar posibles factores asociados a reingreso.Materiales y métodoEstudio de cohorte prospectivo incluyendo pacientes hospitalizados con enfermedades crónicas complejas de un mes a 18 años de edad. Se excluyeron pacientes con enfermedad oncológica y cardiopatías congénitas. Se evaluaron el reingreso a 30 días y el reingreso potencialmente prevenible. Se valoraron características sociodemográficas, geográficas, clínicas y de la transición hacia el cuidado domiciliario.ResultadosSe incluyeron 171 hospitalizaciones; dentro de los 30 días reingresaron 28 pacientes (16,4%; IC95% 11,6-22,7). De los 28 reingresos, 23 (82,1%; IC95% 64,4-92,1) fueron potencialmente prevenibles. La enfermedad respiratoria se asoció con mayor probabilidad de reingreso. No se encontró asociación entre el reingreso a 30 días y los factores de la transición al cuidado domiciliario evaluados.ConclusionesLa tasa de reingreso a 30 días en pacientes con enfermedad crónica compleja fue del 16,4%, y el 82,1% fueron potencialmente prevenibles. Únicamente la enfermedad respiratoria se comportó como factor de riesgo para reingreso a 30 días.

Introduction.Childhood overweight and obesity are a public health problem.The onset of the COVID-19 pandemic may have contributed to this condition.The body mass index (BMI) Z-score has been accepted as an indicator for overweight and obesity diagnosis and follow-up.Objective.To assess whether the prevalence of overweight and obesity and the BMI Z-score in children aged 2 to 5 years increased during the pandemic. Population and methods.Retrospective, cohort study.Patients included were those seen at public health care facilities in the City of Buenos Aires (CABA), who were aged 2 to 5 years, had weight and height values recorded at 2 different visits, before and after the establishment of the preventive and mandatory social isolation policy.Patients' nutritional status (BMI Z-score) and the variation in this indicator between both visits were recorded. Results.A total of 3866 subjects were assessed; their average age was 3.4 ± 0.8 years; 48.1% were girls.The average interval between both visits was 14.3 ± 2.5 months.The prevalence of overweight/ obesity increased from 12.6% (95% CI: 11.6-13.6)to 20.9% (95% CI: 19.6-22.2),p < 0.001, and so did the BMI Z-score (0.4 ± 1.1 versus 0.8 ± 1.3, p < 0.001). Conclusion.The prevalence of overweight and obesity and the BMI Z-score in children aged 2 to 5 years increased significantly during the pandemic.

BackgroundFollicular helper T cells (Tfh) are pivotal in B cell responses. Activation of the purinergic receptor P2X7 on Tfh cells regulates their activity. We investigated the ATP-P2X7R axis in circulating Tfh (cTfh) cells during Respiratory Syncytial Virus (RSV) infection.MethodsWe analyzed two cohorts: children with RSV infection (moderate, n=30; severe, n=21) and healthy children (n=23). We utilized ELISA to quantify the levels of PreF RSV protein-specific IgG antibodies, IL-21 cytokine, and soluble P2X7R (sP2X7R) in both plasma and nasopharyngeal aspirates (NPA). Additionally, luminometry was employed to determine ATP levels in plasma, NPA and supernatant culture. The frequency of cTfh cells, P2X7R expression, and plasmablasts were assessed by flow cytometry. To evaluate apoptosis, proliferation, and IL-21 production by cTfh cells, we cultured PBMCs in the presence of Bz-ATP and/or P2X7R antagonist (KN-62) and a flow cytometry analysis was performed.ResultsIn children with severe RSV disease, we observed diminished titers of neutralizing anti-PreF IgG antibodies. Additionally, severe infections, compared to moderate cases, were associated with fewer cTfh cells and reduced plasma levels of IL-21. Our investigation revealed dysregulation in the ATP-P2X7R pathway during RSV infection. This was characterized by elevated ATP levels in both plasma and NPA samples, increased expression of P2X7R on cTfh cells, lower levels of sP2X7R, and heightened ATP release from PBMCs upon stimulation, particularly evident in severe cases. Importantly, ATP exposure decreased cTfh proliferative response and IL-21 production, while promoting their apoptosis. The P2X7R antagonist KN-62 mitigated these effects. Furthermore, disease severity positively correlated with ATP levels in plasma and NPA samples and inversely correlated with cTfh frequency.ConclusionOur findings indicate that activation of the ATP-P2X7R pathway during RSV infection may contribute to limiting the cTfh cell compartment by promoting cell death and dysfunction, ultimately leading to increased disease severity.

Respiratory syncytial virus (RSV) causes significant morbidity and mortality in children aged ≤ 5 years and adults aged ≥ 60 years worldwide. Despite this, RSV-specific therapeutic options are limited. Rilematovir is an investigational, orally administered inhibitor of RSV fusion protein-mediated viral entry. To establish the antiviral activity, clinical outcomes, safety, and tolerability of rilematovir (low or high dose) in children aged ≥ 28 days and ≤ 3 years with RSV disease. CROCuS was a multicenter, international, double-blind, placebo-controlled, randomized, adaptive phase II study, wherein children aged ≥ 28 days and ≤ 3 years with confirmed RSV infection who were either hospitalized (Cohort 1) or treated as outpatients (Cohort 2) were randomized (1:1:1) to receive rilematovir (low or high dose) or placebo. Study treatment was administered daily as an oral suspension from days 1 to 7, with dosing based on weight and age groups. The primary objective was to establish antiviral activity of rilematovir by evaluating the area under the plasma concentration–time curve of RSV viral load in nasal secretions from baseline through day 5. Severity and duration of RSV signs and symptoms and the safety and tolerability of rilematovir were also assessed through day 28 (± 3). In total, 246 patients were randomized, treated, and included in the safety analysis population (Cohort 1: 147; Cohort 2: 99). Of these, 231 were included in the intent-to-treat-infected analysis population (Cohort 1: 138; Cohort 2: 93). In both cohorts, demographics were generally similar across treatment groups. In both cohorts combined, the difference (95

Introducción: El cambio climático global podría alterar la circulación del virus sincicial respiratorio (VSR).Objetivo: Evaluar modificaciones en la circulación de VSR en los últimos 25 años y su correlación con la temperatura ambiente.Métodos: Estudio transversal, utilizando registros de VSR y temperatura de la Ciudad de Buenos Aires (1995-2019). Para cada año, describimos inicio, fin y duración de la temporada de VSR y evaluamos su correlación con la temperatura media anual.Resultados: Se identificaron 10183 infecciones por VSR. La duración de la temporada disminuyó significativamente (1995: 29 semanas vs. 2019: 18 semanas; R: 0.6 (p< 0,001)), debido a una finalización más precoz (1995: semana 45 vs. 2019: semana 34; 0,6 (p<0,001)). No se observó correlación entre temperatura media anual y duración, comienzo ni finalización de la temporada de VSR.Conclusión: En los últimos 25 años, la duración de la temporada de VSR se acortó significativamente, sin correlación con la temperatura.

Introduction:Air pollution would increase the risk of severe infection repiratory in pediatrics. Research Sources: Environmental Protection Agency, National Meteorological. Service and Integral Health History of the Hospital Management System. Population: Patients under 2 years old who consulted for severe infection repiratory in effectors of Buenos Aires City Government and lived commune with continuous environmental monitoring during 2018. Predictors were daily levels of air pollutants (carbon monoxide, nitrous dioxide, particulate matter < 10 μ). Pollutants were measured at three monitoring stations. Temporal variables (media temperature), sex and effector were controlled. Result Variable: Total numbers of visits and total numbers of visits for severe infection respiratory. To select in the data base the visits to analyze an operative definition was made. Objective:Review impact of air pollution visits for severe infection repiratory in effectors of Buenos Aires City Government. Method:Ecologic research, time-series. Results:80.287 visits were registered, 24.847 for severe infection respiratory (30%). The visits for severe infection respiratory had positive correlation in Cordoba station with N2O (RR: 1,13 [1,00-1,28]). The numbers of visits for severe infection respiratory was higher during cold months than warm months. (19,9% vs 11,9%; RR:1,67 [1,61-1,72]). Conclusion:average values of PM10 and N2O show correlation with the numbers of total visits and visits for severe infection respiratory. The visits increase during winter.

Introducción: La contaminación del aire incrementaría el riesgo de infección respiratoria aguda (IRA) en pediatría. Objetivo: evaluar el impacto de la contaminación del aire en las consultas por IRA realizadas en efectores del Gobierno de la Ciudad de Buenos Aires. Método: estudio ecológico, de series temporales. Fuentes de información: Agencia de Protección Ambiental, Servicio Meteorológico Nacional e Historia de Salud Integral del Sistema de Gestión Hospitalaria. Población: Pacientes menores de 2 años que consultaron por IRA a un efector del GCBA y que residían en una comuna con monitoreo ambiental continuo, durante el 2018. Variables de predicción: Niveles diarios de CO, NO2, PM10 de las estaciones de monitoreo ambiental continuo de la Ciudad Autónoma de Buenos Aires. Variables de resultado: número de consultas totales y por IRA. Variables a controlar: efector, sexo y temperatura media. Se construyó una definición operativa para seleccionar en la base de datos a las consultas objeto de estudio. Resultados: Se registraron 80.287 consultas, 24.847 por IRA (30%). Las consultas por IRA tuvieron correlación positiva en la estación “Córdoba” con el N2O (RR: 1,13 [1,00-1,28]). El número de consultas por IRA en los meses fríos fue mayor que en los cálidos (19,9% vs 11,9%; RR:1,67 [1,61-1,72]). Conclusión: Los valores promedios de PM10 y N2O muestran correlación con el número de las consultas totales y por infección respiratoria aguda, respectivamente. Las consultas se incrementaron durante el invierno.

It has been reported that significant variability in the ethics review process affects multisite studies. We analyzed 1,305 applications for multicenter studies (409 unique protocols), from 1st January 2020 to 20th September 2021. We examined the variability in the times to approval and the first observation and the variation in the level of risk assigned. The median [IQR] variabilities were 42.19 [15.23–82.36] days and 8.00 [3.12–16.68] days, for the times to approval and to the first observation, respectively. There was disagreement in the level of risk assigned by the Research Ethics Committee (REC) in 24.0% of cases. Independent predictors of variability included the number of REC members. In our study, we found substantial variability in the ethics review process among health research protocols. Also, we describe methods to readily measure the delays and the variations in the ethics review process.

La bronquiolitis es el principal motivo de hospitalización en la infancia. La lactancia materna es un factor protector frente a infecciones. Aunque hay evidencia de que la lactancia materna podría prevenir las hospitalizaciones por bronquiolitis, menos claro es su efecto en los pacientes ya hospitalizados por esta enfermedad. Objetivo: Evaluar si existen diferencias en la evolución de pacientes hospitalizados por bronquiolitis alimentados con leche materna exclusiva (LME) vs. sucedáneos de leche materna (SuLM). Pacientes y Método: Estudio de cohorte prospectivo. Se incluyeron niños hospitalizados por bronquiolitis de 1 a 6 meses de edad. Se comparó la evolución respecto a días de hospitalización, días de oxigenoterapia, requerimiento de cánula de alto flujo de oxígeno (CAFO), presencia de neumonía asociada, traslado a terapia intensiva y muerte. Resultados: En el período de estudio 131 lactantes hospitalizados por bronquiolitis cumplieron los criterios de selección: 54 alimentados con LME, 29 con SuLM y 48 recibieron alimentación mixta. El grupo LME requirió significativamente menos días de oxigenoterapia (5,1 ± 2,4 vs. 6,6 ± 3,5; p < 0,02) y hospitalización (7,0 ± 2,4 vs. 8,4 ± 3,6; p < 0,04) que el grupo SuLM. Si bien los varones del grupo SuLM requirieron en promedio más días de hospitalización y oxigenoterapia, esta diferencia no fue estadísticamente significativa. No se registraron fallecimientos en los grupos estudiados. Conclusión: Los pacientes alimentados con LME requirieron menos días de oxigenoterapia y de hospitalización que los que recibieron SuLM.

The review of research protocols by Research Ethics Committees (RECs), essential to ensure the protection of participants, has been managed in the City of Buenos Aires through the PRIISA.BA electronic platform since January 2020. The aim of the present study was to describe ethical review times, their temporal evolution, and predictors of their duration. We conducted an observational study that included all the protocols reviewed between January 2020 and September 2021. Times to approval and to first observation were calculated. Temporal trends in times, and the multivariate association between these and protocol and IRB characteristics were evaluated. 2,781 protocols reviewed in 62 RECs were included. The median time to approval was 29.11 (RIQ 11.29 to 63.35) days, and time to first observation was 8.92 (RIQ 2.05 to 18.18) days. The times were significantly reduced throughout the study period. We detected as variables independently associated with shorter time to approval to be a COVID proposal, having funding and the number of centers to perform the study and having been reviewed by an RECs with more than 10 members. Making observations to the protocol was associated with more time. The results of the present work suggest that ethical review times were reduced during study period. In addition, variables associated with time were identified that could be the object of interventions to improve the process.