Impact of macronutrients intake on glycemic homeostasis of preterm infants: evidence from continuous glucose monitoring.

Nutritional intake could influence the blood glucose profile during early life of preterm infants. We investigated the impact of macronutrient intake on glycemic homeostasis using continuous glucose monitoring (CGM). We analyzed macronutrient intake in infants born ≤ 32 weeks gestational age (GA) and/or with birth weight ≤ 1500 g. CGM was started within 48 h of birth and maintained for 5 days. Mild and severe hypoglycemia were defined as sensor glucose (SG) < 72 mg/dL and <47 mg/dL, respectively, while mild and severe hyperglycemia were SG > 144 mg/dL and >180 mg/dL. Data from 30 participants were included (age 29.9 weeks (29.1; 31.2), birthweight 1230.5 g (1040.0; 1458.6)). A reduced time in mild hypoglycemia was associated to higher amino acids intake (p = 0.011) while increased exposure to hyperglycemia was observed in the presence of higher lipids intake (p = 0.031). The birthweight was the strongest predictor of neonatal glucose profile with an inverse relationship between the time spent in hyperglycemia and birthweight (p = 0.007).  Conclusions: Macronutrient intakes influence neonatal glucose profile as described by continuous glucose monitoring. CGM might contribute to adjust nutritional intakes in preterm infants. What is Known: • Parenteral nutrition may affect glucose profile during the first days of life of preterm infants. What is New: • Continuous glucose monitoring describes the relationship between daily parenteral nutrient intakes and time spent in hypo and hyperglycemic ranges.

The genomic evolutionary dynamics and global circulation patterns of respiratory syncytial virus.

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection in young children and the second leading cause of infant death worldwide. While global circulation has been extensively studied for respiratory viruses such as seasonal influenza, and more recently also in great detail for SARS-CoV-2, a lack of global multi-annual sampling of complete RSV genomes limits our understanding of RSV molecular epidemiology. Here, we capitalise on the genomic surveillance by the INFORM-RSV study and apply phylodynamic approaches to uncover how selection and neutral epidemiological processes shape RSV diversity. Using complete viral genome sequences, we show similar patterns of site-specific diversifying selection among RSVA and RSVB and recover the imprint of non-neutral epidemic processes on their genealogies. Using a phylogeographic approach, we provide evidence for air travel governing the global patterns of RSVA and RSVB spread, which results in a considerable degree of phylogenetic mixing across countries. Our findings highlight the potential of systematic global RSV genomic surveillance for transforming our understanding of global RSV spread.

Clinical and economic burden of respiratory syncytial virus in children aged 0-5 years in Italy.

BACKGROUND: Respiratory syncytial virus (RSV) is among the leading causes of hospitalization due to lower respiratory tract infections (LRTIs) in children younger than 5 years worldwide and the second cause of infant death after malaria. RSV infection occurs in almost all the infants before the second year of life with variable clinical severity, often requiring medical assistance. This analysis investigated patients aged 0-5 years with RSV infection focusing on epidemiology, clinical features, and economic burden of RSV-associated hospitalizations in a setting of Italian real clinical practice. METHODS: An observational retrospective analysis was conducted on administrative databases of healthcare entities covering around 2.6 million residents of whom 120,000 health-assisted infants aged < 5 years. From 2010 to 2018, pediatric patients were included in the presence of hospitalization discharge diagnosis for RSV infections, and RSV-related acute bronchiolitis or pneumonia. Epidemiology, demographics, clinical picture and costs were evaluated in RSV-infected patients, overall and stratified by age ranges (0-1, 1-2, 2-5 years) and compared with an age-matched general population. RESULTS: Overall 1378 RSV-infected children aged 0-5 years were included. Among them, the annual incidence rate of RSV-related hospitalizations was 175-195/100,000 people, with a peak in neonates aged < 1 year (689-806/100,000). While nearly 85% of infected infants were healthy, the remaining 15% presented previous hospitalization for known RSV risk factors, like preterm birth, or congenital heart, lung, and immune diseases. The economic analysis revealed that direct healthcare costs per patient/year were markedly higher in RSV patients than in the general population (3605€ vs 344€). CONCLUSIONS: These findings derived from the real clinical practice in Italy confirmed that RSV has an important epidemiological, clinical, and economic burden among children aged 0-5 years. While the complex management of at-risk infants was confirmed, our data also highlighted the significant impact of RSV infection in infants born at term or otherwise healthy, demonstrating that all infants need protection against RSV disease, reducing then the risk of medium and long-term complications, such as wheezing and asthma.

Lactoferrin in the Prevention of Recurrent Respiratory Infections in Preschool Children: A Prospective Randomized Study.

Few studies have evaluated the effect of bovine lactoferrin (bLf) on reducing respiratory infections in preschool children. This randomized controlled trial evaluated the effect of bLf in preschool children with recurrent respiratory infections. Participants were randomly assigned bLf (n = 25) or control (n = 25). Outcomes included respiratory infection episodes (RIEs), symptom duration, school absence and medication. Fifty children aged 4.2 ± 0.1 years were included. During the active 4-month phase, median number of RIEs was reduced by 50% in the bLf group [1-episode, interquartile range (IQR): 0-2] vs. control (2, IQR: 1-3; p = 0.02). The proportion of participants with >3 RIEs was significantly lower in bLf (n = 1, 4%) vs. control (n = 7, 28%) with 80% lower odds of upper RIEs in the bLf arm (odds ratio: 0.20, 95% CI:0.06-0.74, p = 0.015). The duration of symptoms (3 vs. 6, p = 0.009) and days absent from school (3 vs. 6, p = 0.15) were lower in the active arm. Over the 2-month follow-up, no significant differences were observed between groups for infection episodes, symptom duration or school absence. However, bLf-treated children received significantly less corticosteroids over the entire 6-month study period (32% vs. 60%; p = 0.047). bLf supplementation significantly reduced the frequency and duration of RIEs in children with decreased corticosteroid use.

Critical care of severe bronchiolitis during shortage of ICU resources.

Large seasonal outbreaks of bronchiolitis put pressure on healthcare systems and particularly on intensive care units (ICUs). ICU admission is necessary to provide respiratory support to the severest cases, otherwise bronchiolitis can result in substantial mortality. ICU resources are often insufficient and there is scant evidence to guide the ICU clinical management. Most available studies do not cover the ICU-admitted cases and do not consider the associated public health issues. We review this topic through a multidisciplinary approach from both the clinical and public health perspectives, with an analysis based on pathophysiology and cost-effectiveness. We suggest ways to optimise respiratory care, minimise ICU stay, "protect" ICU beds and, whenever possible, make them available for other critically ill children. We also provide guidance on how to prepare ICUs to work under stressful conditions due to outbreaks and to reduce the risk of nosocomial cross-contamination, particularly in ICUs caring for high-risk children. Funding: None.

A Multi-Omics Approach Reveals Enrichment in Metabolites Involved in the Regulation of the Glutathione Pathway in LIN28B-Dependent Cancer Cells.

The RNA-binding protein LIN28B, identified as an independent risk factor in high-risk neuroblastoma patients, is implicated in adverse treatment outcomes linked to metastasis and chemoresistance. Despite its clinical significance, the impact of LIN28B on neuroblastoma cell metabolism remains unexplored. This study employs a multi-omics approach, integrating transcriptome and metabolome data, to elucidate the global metabolic program associated with varying LIN28B expression levels over time. Our findings reveal that escalating LIN28B expression induces a significant metabolic rewiring in neuroblastoma cells. Specifically, LIN28B prompts a time-dependent increase in the release rate of metabolites related to the glutathione and aminoacyl-tRNA biosynthetic pathways, concomitant with a reduction in glucose uptake. These results underscore the pivotal role of LIN28B in governing neuroblastoma cell metabolism and suggest a potential disruption in the redox balance of LIN28B-bearing cells. This study offers valuable insights into the molecular mechanisms underlying LIN28B-associated adverse outcomes in neuroblastoma, paving the way for targeted therapeutic interventions.

Extracellular Vesicles From Mesenchymal Umbilical Cord Cells Exert Protection Against Oxidative Stress and Fibrosis in a Rat Model of Bronchopulmonary Dysplasia.

Oxidative stress and fibrosis are important stress responses that characterize bronchopulmonary dysplasia (BPD), a disease for which only a therapy but not a cure has been developed. In this work, we investigated the effects of mesenchymal stromal cells-derived extracellular vesicles (MSC-EVs) on lung and brain compartment in an animal model of hyperoxia-induced BPD. Rat pups were intratracheally injected with MSC-EVs produced by human umbilical cord-derived MSC, following the Good Manufacturing Practice-grade (GMP-grade). After evaluating biodistribution of labelled MSC-EVs in rat pups left in normoxia and hyperoxia, oxidative stress and fibrosis investigation were performed. Oxidative stress protection by MSC-EVs treatment was proved both in lung and in brain. The lung epithelial compartment ameliorated glycosaminoglycan and surfactant protein expression in MSC-EVs-injected rat pups compared to untreated animals. Pups under hyperoxia exhibited a fibrotic phenotype in lungs shown by increased collagen deposition and also expression of profibrotic genes. Both parameters were reduced by treatment with MSC-EVs. We established an in vitro model of fibrosis and another of oxidative stress, and we proved that MSC-EVs suppressed the induction of αSMA, influencing collagen deposition and protecting from the oxidative stress. In conclusion, intratracheal administration of clinical-grade MSC-EVs protect from oxidative stress, improves pulmonary epithelial function, and counteracts the development of fibrosis. In the future, MSC-EVs could represent a new cure to prevent the development of BPD.

Nurturing the next generation of pediatric physician scientists: the Padova Physician Scientist Research Training for pediatric residents.

Less than 2% of physicians complete a research training (PhD) after the residency with a declining trend in those pursuing a clinical scientist pathway in pediatrics. The exposure to research methodology during the clinical training may play a role in engaging the next generations of pediatric physician scientist. Herein, we describe the experience of the Padova Physician Scientist Research Training (PPSRT) of the pediatric residency program at the University of Padova. The PPSRT was addressed to residents attending PGY2 to PGY4 of the pediatric program and consisted of two cores: a general one including in person or virtual lectures about research methodology in pediatrics including design of a clinical trial, writing of a scientific paper and statistical methods, and a subspecialties core for the discussion of research challenges in each area and the scientific writing activities. The perceived barriers to a research training and an evaluation of the program were assessed by an anonymized questionnaire. Sixty-four out 150 residents registered for the research training with 62/64 completing the two cores. The major perceived barrier to research during clinical training was the absence of protected time (89%) followed by the lack of specific funds (37%). The group activities lead to the publication of 24 papers.    Conclusion: This is the first experience in the Italian pediatric training of a dedicated research program within the frame of postgraduate medical education. Our report highlights the need for protected time to promote research interest and nurture a new generation of physician scientists. What is Known: • Training to medical research is not part of residency program. • The declining trend of physician scientists might be reverted by early exposure to research methodology and challenges during residency. What is New: • An early exposure to research training during pediatric residency increases the research engagement of pediatric residents. • The lack of protected time for research is perceived as the major barrier to research training during residency.

External Validation of a Multivariate Model for Targeted Surfactant Replacement.

INTRODUCTION: Early targeted surfactant therapy for preterm infants is recommended but the best criteria to personalize treatment are unclear. We validate a previously published multivariate prognostic model based on gestational age (GA), lung ultrasound score (LUS), and oxygen saturation to inspire oxygen fraction ratio (SatO2/FiO2) using an independent data set. METHODS: Pragmatic, observational study in 10 Italian and Spanish NICUs, including preterm babies (250 and 336 weeks divided into 3 GA intervals) with clinical signs of respiratory distress syndrome and stabilized on CPAP. LUS and SatO2/FiO2 were collected soon after stabilization. Their prognostic accuracy was evaluated on the subsequent surfactant administration by a rigorously masked physician. RESULTS: One hundred seventy-five infants were included in the study. Surfactant was given to 74% infants born at 25-27 weeks, 38.5% at 28-30 weeks, and 26.5% at 31-33 weeks. The calibration curve comparing the validation and the development populations showed significant overlap with an intercept = 0.08, 95% CI (-0.34; 0.5) and a slope = 1.53, 95% CI (1.07-1.98). The validation cohort had a high predictive accuracy. Its ROC curve showed an AUC = 0.95, 95% CI (0.91-0.99) with sensitivity = 0.93, 95% CI (0.83-0.98), specificity = 0.81, 95% CI (0.73-0.88), PPV = 0.76, 95% CI (0.65-0.84), NPV = 0.95, 95% CI (0.88-0.98). LUS ≥9 demonstrated the highest sensitivity (0.91, 95% CI [0.82-0.97]) and specificity = 0.81, 95% CI (0.72-0.88) as individual predictor. LUS and SatO2/FiO2 prognostic performances varied with GA. CONCLUSION: We validated a prognostic model based on LUS and Sat/FiO2 to facilitate early, customized surfactant administration that may improve respiratory management of preterm neonates.

Present and future are getting confused: are we equipped to face the technological revolution?

BACKGROUND: This is a commentary reporting the outcome of a workshop promoted by the Department of Woman's and Child's Health of the University of Padua (Italy) focused on the emerging issue of what seems to be the increasing agemone role of technology. MAIN BODY: Over the centuries, technology has always been at the service of science, with theoretical insights anticipating experimental proofs. Over the last decades, however, the situation has radically changed, due to several factors. Technology seems to be playing an agemone role. The present and notably the future generation of scientists have major challenges to face. They have to deal with the forces generated by the infosphera; to dominate the technology and to maintain the capacity of generating inquisitive, creative, ethical and spiritual thoughts capable of addressing new scientific hypotheses and projects directed to the individual and collective good. However, in this scenario, what seems more relevant is to focus all our efforts in preparing ourselves, first, and then the new generations to face these challenges. From this point of view, the academic institutions and the scientific societies, have a major responsibility to deal with. CONCLUSIONS: The academic ecosystem traditionally used to educate the new generation of professionals as well as, and most importantly, the cultural, the professional pathways presently used to form them need to be extensively revised. The time is running short and the stakes are high. The debate is open.

European Respiratory Society short guidelines for the use of as-needed ICS/formoterol in mild asthma

Recent clinical trials of as-needed fixed-dose combination of inhaled corticosteroid (ICS)/formoterol have provided new evidence that may warrant a reconsideration of current practice. A Task Force was set up by the European Respiratory Society to provide evidence-based recommendations on the use of as-needed ICS/formoterol as treatment for mild asthma. The Task Force defined two questions that were assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach. The Task Force utilised the outcomes to develop recommendations for a pragmatic guideline for everyday clinical practice. The Task Force suggests that adults with mild asthma use as-needed ICS/formoterol instead of regular ICS maintenance treatment plus as-needed short-acting ß2-antagonist (SABA) and that adolescents with mild asthma use either as-needed ICS/formoterol or ICS maintenance treatment plus as-needed SABA (conditional recommendation; low certainty of evidence). The recommendation for adults places a relatively higher value on the reduction of systemic corticosteroid use and the outcomes related to exacerbations, and a relatively lower value on the small differences in asthma control. Either treatment option is suggested for adolescent patients as the balance is very close and data more limited. The Task Force recommends that adult and adolescent patients with mild asthma use as-needed ICS/formoterol instead of as-needed SABA (strong recommendation; low certainty of evidence). This recommendation is based on the benefit of as-needed ICS/formoterol in mild asthma on several outcomes and the risks related to as-needed SABA in the absence of anti-inflammatory treatment. The implementation of this recommendation is hampered in countries (including European Union countries) where as-needed ICS/formoterol is not approved for mild asthma.

Low-Field Benchtop NMR to Discover Early-Onset Sepsis: A Proof of Concept.

Low-field (LF) benchtop NMR is a new family of instruments available on the market, promising for fast metabolic fingerprinting and targeted quantification of specific metabolites despite a lack of sensitivity and resolution with respect to high-field (HF) instruments. In the present study, we evaluated the possibility to use the urinary metabolic fingerprint generated using a benchtop LF NMR instrument for an early detection of sepsis in preterm newborns, considering a cohort of neonates previously investigated by untargeted metabolomics based on Mass Spectrometry (MS). The classifier obtained behaved similarly to that based on MS, even if different classes of metabolites were taken into account. Indeed, investigating the regions of interest mainly related to the development of sepsis by a HF NMR instrument, we discovered a set of relevant metabolites associated to sepsis. The set included metabolites that were not detected by MS, but that were reported as relevant in other published studies. Moreover, a strong correlation between LF and HF NMR spectra was observed. The high reproducibility of the NMR spectra, the interpretability of the fingerprint in terms of metabolites and the ease of use make LF benchtop NMR instruments promising in discovering early-onset sepsis.

European Respiratory Society short guidelines for the use of as-needed ICS/formoterol in mild asthma.

Recent clinical trials of as-needed fixed-dose combination of inhaled corticosteroid (ICS)/formoterol have provided new evidence that may warrant a reconsideration of current practice. A Task Force was set up by the European Respiratory Society to provide evidence-based recommendations on the use of as-needed ICS/formoterol as treatment for mild asthma. The Task Force defined two questions that were assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach. The Task Force utilised the outcomes to develop recommendations for a pragmatic guideline for everyday clinical practice. The Task Force suggests that adults with mild asthma use as-needed ICS/formoterol instead of regular ICS maintenance treatment plus as-needed short-acting ß2-antagonist (SABA) and that adolescents with mild asthma use either as-needed ICS/formoterol or ICS maintenance treatment plus as-needed SABA (conditional recommendation; low certainty of evidence). The recommendation for adults places a relatively higher value on the reduction of systemic corticosteroid use and the outcomes related to exacerbations, and a relatively lower value on the small differences in asthma control. Either treatment option is suggested for adolescent patients as the balance is very close and data more limited. The Task Force recommends that adult and adolescent patients with mild asthma use as-needed ICS/formoterol instead of as-needed SABA (strong recommendation; low certainty of evidence). This recommendation is based on the benefit of as-needed ICS/formoterol in mild asthma on several outcomes and the risks related to as-needed SABA in the absence of anti-inflammatory treatment. The implementation of this recommendation is hampered in countries (including European Union countries) where as-needed ICS/formoterol is not approved for mild asthma.

A new cost-utility analysis assessing risk factor-guided prophylaxis with palivizumab for the prevention of severe respiratory syncytial virus infection in Italian infants born at 29-35 weeks' gestational age.

Since the last Italian cost-utility assessment of palivizumab in 2009, new data on the burden of respiratory syncytial virus (RSV) and an International Risk Scoring Tool (IRST) have become available. The objective of this study was to provide an up-to-date cost-utility assessment of palivizumab versus no prophylaxis for the prevention of severe RSV infection in otherwise healthy Italian infants born at 29-31 weeks' gestational age (wGA) infants and those 32-35wGA infants categorized as either moderate- or high-risk of RSV-hospitalization (RSVH) by the IRST. A decision tree was constructed in which infants received palivizumab or no prophylaxis and then could experience: i) RSVH; ii) emergency room medically-attended RSV-infection (MARI); or, iii) remain uninfected/non-medically attended. RSVH cases that required intensive care unit admission could die (0.43%). Respiratory morbidity was considered in all surviving infants up to 18 years of age. Hospitalization rates were derived from Italian data combined with efficacy from the IMpact-RSV trial. Palivizumab costs were calculated from vial prices (50mg: €490.37 100mg: €814.34) and Italian birth statistics combined with a growth algorithm. A lifetime horizon and healthcare and societal costs were included. The incremental cost-utility ratio (ICUR) was €14814 per quality-adjusted life year (QALY) gained in the whole population (mean: €15430; probability of ICUR being <€40000: 0.90). The equivalent ICURs were €15139 per QALY gained (€15915; 0.89) for 29-31wGA infants and €14719 per QALY gained (€15230; 0.89) for 32-35wGA infants. The model was most sensitive to rates of long-term sequelae, utility scores, palivizumab cost, and palivizumab efficacy. Palivizumab remained cost-effective in all scenario analyses, including a scenario wherein RSVH infants received palivizumab without a reduction in long-term sequelae and experienced a 6-year duration of respiratory morbidity (ICUR: €27948 per QALY gained). In conclusion, palivizumab remains cost-effective versus no prophylaxis in otherwise healthy Italian preterm infants born 29-35wGA. The IRST can help guide cost-effective use of palivizumab in 32-35wGA infants.

Efficacy and safety of ketamine for neonatal refractory status epilepticus: case report and systematic review.

Background: Evidence-based data on treatment of neonatal status epilepticus (SE) are scarce. We aimed to collect data on the efficacy and safety of ketamine for the treatment of neonatal SE and to assess its possible role in the treatment of neonatal SE. Methods: We described a novel case and conducted a systematic literature review on neonatal SE treated with ketamine. The search was carried out in Pubmed, Cochrane, Clinical Trial Gov, Scopus and Web of Science. Results: Seven published cases of neonatal SE treated with ketamine were identified and analyzed together with our novel case. Seizures typically presented during the first 24 h of life (6/8). Seizures were resistant to a mean of five antiseizure medications. Ketamine, a NMDA receptor antagonist, appeared to be safe and effective in all neonates treated. Neurologic sequelae including hypotonia and spasticity were reported for 4/5 of the surviving children (5/8). 3/5 of them were seizure free at 1-17 months of life. Discussion: Neonatal brain is more susceptible to seizures due to a shift towards increased excitation because of a paradoxical excitatory effect of GABA, a greater density of NMDA receptors and higher extracellular concentrations of glutamate. Status epilepticus and neonatal encephalopathy could further enhance these mechanisms, providing a rationale for the use of ketamine in this setting. Conclusions: Ketamine in the treatment of neonatal SE showed a promising efficacy and safety profile. However, further in-depth studies and clinical trials on larger populations are needed.

Deep Medullary Vein Thrombosis in Newborns: A Systematic Literature Review.

BACKGROUND: Deep medullary vein (DMV) thrombosis is a rare cause of brain damage in both preterm and full-term neonates. In this study, we aimed to collect data on clinical and radiological presentation, treatment, and outcome of neonatal DMV thrombosis. METHODS: Systematic literature review on neonatal DMV thrombosis was carried out in PubMed, ClinicalTrial.gov, Scopus, and Web of Science up to December 2022. RESULTS: Seventy-five published cases of DMV thrombosis were identified and analysed (preterm newborns were 46%). Neonatal distress, respiratory resuscitation, or need for inotropes were present in 34/75 (45%) of patients. Signs and symptoms at presentation included seizures (38/75, 48%), apnoea (27/75, 36%), lethargy or irritability (26/75, 35%). At magnetic resonance imaging (MRI), fan-shaped linear T2 hypointense lesions were documented in all cases. All had ischaemic injuries, most often involving the frontal (62/74, 84%) and parietal lobes (56/74, 76%). Signs of haemorrhagic infarction were present in 53/54 (98%). Antithrombotic treatment was not mentioned in any of the studies included. Although mortality was low (2/75, 2.6%), a large proportion of patients developed neurological sequelae (intellectual disability in 19/51 [37%] and epilepsy in 9/51 [18%] cases). CONCLUSIONS: DMV thrombosis is rarely identified in the literature, even if it is possibly under-recognized or under-reported. Presentation in neonatal age is with seizures and non-specific systemic signs/symptoms that often cause diagnostic delay, despite the pathognomonic MRI picture. The high rate of morbidity, which determines significant social and health costs, requires further in-depth studies aimed at earlier diagnosis and evidence-based prevention and therapeutic strategies.

Neurosteroid pathway derangement in asphyctic infants treated with hypothermia: an untargeted metabolomic approach.

BACKGROUND: The pathobiological mechanisms associated with perinatal asphyxia and hypoxic-ischemic encephalopathy are complex and poorly understood. The metabolic effects of therapeutic hypothermia have been partially explored. METHODS: We conducted a single-center longitudinal study to investigate the metabolic effects of perinatal asphyxia and hypoxic-ischemic encephalopathy on the urinary metabolome of a group of 12 asphyctic infants over time compared to 22 matched healthy newborns, using untargeted metabolomics based on mass spectrometry. FINDINGS: Over-representation pathway analysis identified the steroidogenesis pathway as being significantly disrupted, with reduced steroid levels in the first three days of life despite treatment with hypothermia. Comparison with matched healthy newborns showed that the urinary steroid content was lower in asphyctic infants before hypothermia. The lysine degradation and carnitine synthesis pathways were also significantly affected. INTERPRETATION: Steroidogenesis is significantly disrupted in asphyctic infants compared to healthy newborns. Given how neurosteroids are involved in neuromodulation and neuroprotection, translational research is warranted on the potential role of neurosteroid-based intervention in asphyctic infants. FUNDING: None.

Assessing the burden of bronchiolitis and lower respiratory tract infections in children ≤24 months of age in Italy, 2012-2019.

Background: Bronchiolitis is the most common lower respiratory tract infection (LRTI) in children and is mainly caused by the Respiratory Syncytial Virus (RSV). Bronchiolitis presents seasonally and lasts about five months, usually between October to March, with peaks of hospitalizations between December and February, in the Northern Hemisphere. The burden of bronchiolitis and RSV in primary care is not well understood. Materials and methods: This retrospective analysis used data from Pedianet, a comprehensive paediatric primary care database of 161 family paediatricians in Italy. We evaluated the incidence rates (IR) of all-cause bronchiolitis (ICD9-CM codes 466.1, 466.11 or 466.19), all-cause LRTIs, RSV-bronchiolitis and RSV-LRTIs in children from 0 to 24 months of age, between January 2012 to December 2019. The role of prematurity (<37 weeks of gestational age) as a bronchiolitis risk factor was evaluated and expressed as odds ratio. Results: Of the 108,960 children included in the study cohort, 7,956 episodes of bronchiolitis and 37,827 episodes of LRTIs were recorded for an IR of 47 and 221 × 1,000 person-years, respectively. IRs did not vary significantly throughout the eight years of RSV seasons considered, showing a seasonality usually lasting five months, between October and March, while the peak of incidence was between December and February. Bronchiolitis and LRTI IRs were higher during the RSV season, between October and March, regardless of the month of birth, with bronchiolitis IR being higher in children aged ≤12 months. Only 2.3% of bronchiolitis and LRTI were coded as RSV-related. Prematurity and comorbidity increased the risk of bronchiolitis; however, 92% of cases happened in children born at term, and 97% happened in children with no comorbidities or otherwise healthy. Conclusions: Our results confirm that all children aged ≤24 months are at risk of bronchiolitis and LRTI during the RSV season, regardless of the month of birth, gestational age or underlying health conditions. The IRs of bronchiolitis and LRTI RSV-related are underestimated due to the poor outpatient epidemiological and virological surveillance. Strengthening the surveillance system at the paediatric outpatient level, as well as at the inpatient level, is needed to unveil the actual burden of RSV-bronchiolitis and RSV-LRTI, as well as to evaluate the effectiveness of new preventive strategies for anti-RSV.