Human respiratory syncytial virus (hRSV) is a significant cause of respiratory tract infections, particularly in young children and older adults. In this review, we aimed to comprehensively summarize what is known about the immune response to hRSV infection. We described the innate and adaptive immune components involved, including the recognition of RSV, the inflammatory response, the role of natural killer (NK) cells, antigen presentation, T cell response, and antibody production. Understanding the complex immune response to hRSV infection is crucial for developing effective interventions against this significant respiratory pathogen. Further investigations into the immune memory generated by hRSV infection and the development of strategies to enhance immune responses may hold promise for the prevention and management of hRSV-associated diseases.

BACKGROUND: The epidemiology of respiratory syncytial virus (RSV) infection has changed during the COVID-19 pandemic. Our objectives were to describe the RSV epidemic in 2021 and compare it with the previous years to the pandemic.
METHODS: Retrospective study performed in Madrid (Spain) in a large pediatric hospital comparing the epidemiology and clinical data of RSV admissions during 2021 and the two previous seasons.
RESULTS: 899 children were admitted for RSV infection during the study period. During 2021, the outbreak peaked in June and the last cases were identified in July. Previous seasons were detected in autumn-winter. The number of admissions in 2021 was significantly lower than in previous seasons. There were no differences between seasons regarding age, sex or disease severity.
CONCLUSIONS: RSV hospitalizations during 2021 in Spain moved to summer with no cases in autumn and winter 2020-2021. Unlike other countries, clinical data were similar between epidemics.

Acute respiratory infections (ARIs) are the most prevalent diseases in children under 5 years old, and viruses are the leading cause. ARIs arise due to numerous factors, including age, contact with siblings or other children in daycare centers, and environmental pollution. Breastfeeding reportedly confers protection against ARIs through bioactive components related to mucous epithelial immunity. This study aimed to evaluate the frequency and severity of viral ARIs in hospitalized children, together with the status and duration of exclusive breastfeeding (EBF) and other associated factors. It comprised an epidemiological surveillance study to investigate respiratory viruses in hospitalized children, in which demographic and clinical data were collected. Overall, 279 patients were included, 190 (68%) had positive viral results, and 132 (47%) were exclusively breastfed. In an adjusted analysis, it was observed that older children, the parents\' educational level, and the presence of chronic disease were significantly related to EBF for more than 6 months. No significant differences were observed in viral positivity and disease severity concerning EBF. Whereas the EBF status was associated with a positive rate of virus detection, the significance did not remain after adjustment, and it was not considered a protective factor against ARIs. On the other hand, young age and exposure to tobacco were confirmed as risk factors of frequency and severity, respectively. Such confounding factors can impact the analysis and should be considered in future studies.

UNASSIGNED: The epidemiology of respiratory syncytial virus (RSV) infection has changed during the COVID-19 pandemic. Our objectives were to describe the RSV epidemic in 2021 and compare it with the previous years to the pandemic.
UNASSIGNED: Retrospective study performed in Madrid (Spain) in a large pediatric hospital comparing the epidemiology and clinical data of RSV admissions during 2021 and the two previous seasons.
UNASSIGNED: 899 children were admitted for RSV infection during the study period. During 2021, the outbreak peaked in June and the last cases were identified in July. Previous seasons were detected in autumn-winter. The number of admissions in 2021 was significantly lower than in previous seasons. There were no differences between seasons regarding age, sex or disease severity.
UNASSIGNED: RSV hospitalizations during 2021 in Spain moved to summer with no cases in autumn and winter 2020-2021. Unlike other countries, clinical data were similar between epidemics.
UNASSIGNED: La epidemiología de la infección por virus respiratorio sincitial (VRS) ha cambiado durante la pandemia de COVID-19. Nuestros objetivos fueron describir la epidemia de VRS en 2021 y compararla con las de los años previos a la pandemia.
UNASSIGNED: Estudio retrospectivo realizado en Madrid (España), en un hospital pediátrico terciario, que compara los datos epidemiológicos y clínicos de los ingresos por VRS durante 2021 y las 2 temporadas anteriores.
UNASSIGNED: Ingresaron 899 niños por infección por VRS en el período de estudio. Durante 2021, el brote alcanzó su punto máximo en junio y los últimos casos se identificaron en julio. En las temporadas anteriores se detectaron en otoño-invierno. El número de hospitalizaciones en 2021 fue significativamente menor que en temporadas anteriores. No hubo diferencias entre temporadas en cuanto a edad, sexo o gravedad de la enfermedad.
UNASSIGNED: Las hospitalizaciones por VRS durante 2021 en España se trasladaron a verano, sin casos en otoño e invierno 2020-2021. A diferencia de otros países, los datos clínicos fueron similares entre epidemias.

A total of 281 clinical specimens (nasal swabs and nasopharyngeal aspirates) were tested with the Xpert® Flu/RSV XC. The results were compared to those obtained with the real-time retro transcriptase-polymerase chain reaction assays routinely used in our laboratory. The Xpert® Flu/RSV XC showed sensitivity/specificity of 97.8%/100% and 97.9%/100% for flu and respiratory syncytial virus, respectively.

BACKGROUND: How pediatricians manage bronchiolitis and the derived total costs (direct and indirect) in the emergency department (ED) have not been fully characterized. The aim of the present study is to calculate those costs in a European country.
METHODS: A prospective and observational study, including 10 EDs of tertiary hospitals throughout Spain and during the bronchiolitis season 2010-2011, was performed. Every ED recruited children on random days of the week (3 days per week; always including one non-working day per every week). Recruitment aimed at a total sample size of 600 children. Direct (diagnostic procedures, time spent in the ED and medication) and indirect costs (work hours lost by parents, babysitting, travels, and meals) were collected. Comparisons between bronchiolitis caused by respiratory syncytial virus (RSV) and non-RSV bronchiolitis, as well as costs across severity categories were performed with the Kruskal-Wallis test. A multiple regression model was built to assess the influence of several of the studied factors on the total costs, including a RSV positive test and episode severity as independent variables; and gender, age, attending nursery school, preterm birth, low birth weight, smoker mother during pregnancy, and current smoker father as covariates.
RESULTS: From the 664 recruited children, direct mean costs were €213.2 ± 91.8 and indirect ones were €35.9 ± 55.3; the total costs being €249.2 ± 122.9. Costs were significantly higher in children positive to RSV and rose with increased severity. Those associations were maintained in the multiple regression analysis.
CONCLUSIONS: Although relatively low at the individual level (€249.2, mean total cost) the costs for just the ED expenses of bronchiolitis in Spain would add up to about €20 million per year.