Bronchiolitis before and after the SARS-CoV-2 pandemic: Twelve years of experience in a Spanish paediatric hospital.

INTRODUCTION: Acute bronchiolitis is the main cause of hospitalization in children under 2 years of age, with a regular seasonality, mostly due to the respiratory syncytial virus. OBJECTIVES: To describe the epidemiology of bronchiolitis hospitalizations in our center in the last 12 years, and analyze the changes in clinical characteristics, microbiology, and adverse outcomes during the SARS-CoV-2 pandemic. METHODS: Observational study including patients admitted for bronchiolitis between April 2010 and December 2021 in a Spanish tertiary paediatric hospital. Relevant demographic, clinical, microbiological, and adverse outcome variables were collected in an anonymized database. The pandemic period (April 2020 to December 2021) was compared to 2010-2015 seasons using appropriate statistical tests. RESULTS: There were 2138 bronchiolitis admissions, with a mean of 195.6 per year between 2010 and 2019 and a 2-4-month peak between November and March. In the expected season of 2020, there was a 94.4% reduction of bronchiolitis hospitalizations, with only 11 cases admitted in the first year of the pandemic. Bronchiolitis cases increased from the summer of 2021 during a 6-month long peak, reaching a total of 171 cases. Length of stay was significantly shorter during the pandemic, but no differences were found in clinical and microbiological characteristics or other adverse outcomes. CONCLUSIONS: The SARS-CoV-2 pandemic has modified the seasonality of bronchiolitis hospitalizations, with a dramatic decrease in cases during the expected season of 2020-2021, and an extemporaneous summer-autumn peak in 2021 with longer duration but similar patient characteristics and risk factors.

Does exposure of pregnant women to epidemic respiratory syncytial virus affect the severity of bronchiolitis?

INTRODUCTION: Passive transplacental immunity against respiratory syncytial virus (RSV) appears to mediate in the protection of the infant for the first 6 months of life. Lower environmental exposure in pregnant women to RSV epidemic may influence the susceptibility of these infants to infection by lowering the levels of antibodies that are transferred to the fetus. OBJECTIVES: To contrast the risk of severe disease progression in infants with acute bronchiolitis by RSV, according to the mother's level of exposure to epidemic. METHOD: Retrospective cohort study of previously healthy infants with RSV-acute bronchiolitis during 5 epidemics was made. We compared the severity of the infection in those born during the period of risk (when is less likely the mother's exposure to epidemic and the transfer of antibodies to the fetus: October 15th-December 15th in our latitude) with the rest of acute bronchiolitis. Bivariate analysis was performed regarding birth in period of risk and the rest of variables, using the Chi-square test. Multivariate logistic regression analysis was performed to study possible classical confounding factors. RESULTS: 695 infants were included in the study. 356 infants were born during the period of risk. Of the 56 patients requiring admission to PICU, 40 of them (71.4%) were born in this period (p=0.002). In the multivariate analysis, the birth in the period of risk showed a 6.5 OR (95% CI: 2.13-19.7) independently of the rest of variables. CONCLUSIONS: The worst clinical disease progression of the acute bronchiolitis by the RSV in less than 6 months age is related to lower exposure of the pregnant woman to the RSV epidemic.

[Lower lymphocyte response in severe cases of acute bronchiolitis due to respiratory syncytial virus]. / Menor respuesta linfocitaria en casos graves de bronquiolitis aguda por virus respiratorio sincitial.

INTRODUCTION: Acute bronchiolitis (AB) of the infant has a serious outcome in 6-16% of the hospital admitted cases. Its pathogenesis and evolution is related to the response of the T lymphocytes. The objective of the present study is to determine if the lower systemic lymphocytic response is related to a worse outcome of AB in hospitalised infants. PATIENTS AND METHOD: Retrospective observational-analytical study of cases-controls nested in a cohort of patients admitted due to RSV-AB between the period from October 2010 to March 2015. Those with a full blood count in the first 48hours of respiratory distress were included. Infants with underlying disease, bacterial superinfection, and premature infants <32 weeks of gestation were excluded. The main dichotomous variable was PICU admission. Other variables were: gender, age, post-menstrual age, gestational and post-natal tobacco exposure, admission month, type of lactation, and days of onset of respiratory distress. Lymphocyte counts were categorised by quartiles. Bivariate analysis was performed with the main variable and then by logistic regression to analyse confounding factors. RESULTS: The study included 252 infants, of whom 6.6% (17) required PICU admission. The difference in mean±SD of lymphocytes for patients admitted to and not admitted to PICU was 4,044±1755 and 5,035±1786, respectively (Student-t test, P<.05). An association was found between PICU admission and lymphocyte count <3700/ml (Chi-squared, P=.019; OR: 3.2) and it was found to be maintained in the logistic regression, regardless of age and all other studied factors (Wald 4.191 P=.041, OR: 3.8). CONCLUSIONS: A relationship was found between lymphocytosis <3700/ml in the first days of respiratory distress and a worse outcome in previously healthy infants <12 months and gestational age greater than 32 weeks with RSV-AB.

[Validation study of an acute bronchiolitis severity scale to determine admission to a Paediatric Intensive Care Unit]. / Estudio de validez de una escala de gravedad de la bronquiolitis aguda para orientar el ingreso en UCIP.

INTRODUCTION: At present, there are few validated scoring tests for assessing acute bronchiolitis (AB) severity, and limited information on their test power. The aim of the present study is to evaluate the validity of an acute bronchiolitis severity score (ABSS) to help in deciding PICU admission. PATIENTS AND METHOD: Prospective, descriptive, observational study of previously healthy infants under 1 year of age with AB, where the ABSS was used to compare severity as regards the need for PICU admission. The sample size was estimated as at least 175 patients. The research team was trained in the use of ABSS. All patients in the study were evaluated with ABSS daily, as well as in the case of clinical deterioration. The initial and maximum ABSS scores were contrasted to the need for PICU admission. A receiver operative curve was constructed, and the area under the curve was calculated, and the optimum point of sensitivity / specificity was estimated. RESULTS: The study included a total of 190 patients (male / female: 58% / 42%). PICU was required in 11 (6%). The mean± SD ABSS-maximal score for patients who required and did not require PICU was 10.55± 1.12 and 6.35± 2.3, respectively (P<.001). The AUC for ABSS-maximal was 0.94 (P<.001, 95% CI: 0.90-0.98). The optimal cut-off point was set at ≥10 points for a sensitivity of 82% and a specificity of 91%. CONCLUSIONS: ABSS estimates the severity of AB regarding the need for PICU admission, with a sensitivity and specificity of clinical usefulness.

[Prediction of Severe Course in Infants with RSV Bronchiolitis under 6 Months. Spain]. / Predicción de la evolución de la bronquiolitis por virus respiratorio sincitial en lactantes menores de 6 meses.

OBJECTIVE: The need for mechanical ventilation (MV) in acute bronchiolitis (AB) by respiratory syncytial virus (RSV) varies depending on the series (6-18%). Our goal is to determine the admissions to PICU for MV in patients under 6 months with AB and define the risk factors for building a prediction model. METHODS: Retrospective study of patients younger than 6 months admitted by BA-VRS between the periods April 1, 2010 and March 31, 2015 was made. The primary variable was the admission to PICU for MV. Related addition, to find risk factors in a model of binary logistic regression clinical variables were collected. A ROC curve model was developed and optimal cutoff point was identified. RESULTS: In 695 cases, the need of MV in the PICU (Y) was 56 (8.1%). Risk factors (Xi) included in the equation were: 1. male sex (OR 4.27) 2. postmenstrual age (OR: 0.76) 3. Weight income less than p3 (OR: 5.53) 4. intake lees than 50% (OR: 12.4) 5. Severity by scale (OR: 1.58) 6. apneas before admission (OR: 25.5) 7. bacterial superinfection (OR 5.03) and 8. gestational age more than 37 weeks OR (0.32). The area under the curve, sensitivity and specificity were 0.943, 0.84 and 0.93 respectively. CONCLUSIONS: The PICU admission for MV was 8.1 in every 100 healthy infants hospitalized for AB and year. The prediction model equation can help to predict patients at increased risk of severe evolution.

OBJETIVO: La necesidad de ventilación mecánica (VM) en la bronquiolitis aguda por el virus respiratorio sincitial (VRS) varía según las series entre el 6 y el 18 %. Nuestro objetivo fue conocer los ingresos en la unidad de cuidados intensivos para VM de pacientes con bronquiolitis aguda menores de 6 meses y definir los factores de riesgo con el fin de construir un modelo de predicción. METODOS: Estudio retrospectivo de pacientes menores de 6 meses ingresados por bronquiolitis aguda por VRS entre los periodos 1 de abril de 2010 y 31 de marzo de 2015. La variable principal fue el ingreso en la unidad de cuidados intensivos pediátricos para ventilación mecánica. Además, se recogieron variables clínicas relacionadas para hallar factores de riesgo en un modelo de regresión logística binaria. Con el modelo se elaboró una curva ROC y se identificó un punto óptimo de corte. RESULTADOS: De 695 casos, precisaron VM 56 (8,1%). Los factores de riesgo (Xi) incluidos en la ecuación fueron: 1. Sexo varón (OR: 4,27) 2. Edad postmenstrual (OR:0,76) 3. Peso al ingreso inferior a p3(OR: 5,53) 4. Ingesta inferior a 50% (OR:12,4), 5. Gravedad por escala (OR:1,58), 6. Apneas antes del ingreso (OR:25,5) 7. Sobreinfección bacteriana (OR: 5,03) y 8. Edad gestacional superior a 37 semanas OR (0,32). El área bajo la curva, sensibilidad y especificidad fueron 0,943; 0,84 y 0,93 respectivamente. CONCLUSIONES: Los ingresos en UCIP para VM fueron 8,1 por cada 100 lactantes sanos hospitalizados por BA y año. La ecuación elaborada del modelo de predicción puede ser de ayuda para predecir los pacientes con mayor riesgo de evolución grave.

[Epidemiology of patients hospitalised due to bronchiolitis in the south of Europe: Analysis of the epidemics, 2010-2015]. / Epidemiología de los ingresos por bronquiolitis en el sur de Europa: análisis de las epidemias 2010-2015.

INTRODUCTION: The renewal of clinical practice guidelines on acute bronchiolitis (AB) requires the re-assessment of the consequences of their implementation. An update is presented on the main clinical and epidemiological variables in patients hospitalised due to AB in Southern Europe and an analysis made of the causes associated with longer hospital stay. PATIENTS AND METHOD: A retrospective study was conducted on patients admitted to hospital due to AB during 5 epidemics (2010-2015), with an analysis of the major clinical and epidemiological variables. A logistic regression analysis was performed on the factors associated with a longer hospital stay. RESULTS: The beginning of the epidemic occurred between the 4th week of September and the 3rd week of October. Of those children under 2 years (42,530), 15.21% (6,468 patients) attended paediatric emergency department due to having AB, and 2.36% (1,006 patients) were admitted. Of these, 18.5% of were premature, 12.2% had a birth weight <2,300g, 21.1% were younger than 1 month, 10.8% consulted for associated apnoea, 31.1% had an intake <50%, and 13.1% had bacterial superinfection. These factors were independently associated with prolonged stay. The median length of stay was 5 days, and 8.5% of cases were admitted to a paediatric intensive care unit (PICU). CONCLUSIONS: The beginning of the bronchiolitis epidemic showed a variability of up to 4 weeks in this region. Five years after implementing the new guidelines, the incidence of admissions was approximately 2.3%, and appeared stable compared to previous studies. The mean age of the patients decreased to 2.4 months, although with a similar proportion of PICU admissions of 8.5%. Independent factors associated with prolonged stay were: low birth weight, age less than one month, apnoea prior-to-admission, intake of less than 50%, and severe bacterial superinfection. Respiratory bacterial infection exceeded the prevalence of urinary tract infection.