The diffusion of the SARS‐CoV‐2 virus and the implementation of restrictive measures led to a drastic reduction of respiratory syncytial virus (RSV) diffusion. Few RSV cases have been detected worldwide, even after the removal of the restrictions. We review the current literature and present possible explanations on why there has been a significant reduction of RSV detection during the COVID‐19 pandemic. We also hypothesize what may happen when RSV begins to circulate again. The increase of an immunologically naïve population, with infants born from mothers who have not reinforced their immunity to RSV, could lead to greater RSV epidemics in the coming seasons. It is crucial to prepare the scientific community and to keep RSV surveillance active to avoid dramatic consequences.

Background The role of human bocavirus (HBoV) as a respiratory pathogen has not been fulfilled yet. We aimed to describe clinical and serological characteristics of children with HBoV hospitalized for acute respiratory tract infection and to evaluate whether differences occur between HBoV alone and in co-infection. Methods We retrospectively reviewed data from 60 children (median age of 6.2 months, range 0.6-70.9) hospitalized for acute respiratory symptoms, with HBoV detected from a respiratory sample, using a reverse transcriptase-PCR for 14 respiratory viruses (including respiratory syncytial virus (RSV), influenza virus A and B, human coronavirus OC43, 229E, NL-63 and HUK1, adenovirus, rhinovirus, parainfluenza virus1-3, and human metapneumovirus).Results HBoV was detected alone in 29 (48.3%) patients, while in co-infection with other viruses in 31 patients (51.7%), with a peak between December and January. Among the 60 patients, 34 were bronchiolitis, 19 wheezing, 3 pneumonia, 2 upper respiratory tract infection, and 2 whooping cough. Seven children (11.6%) required admission to the paediatric intensive care unit (PICU) for respiratory failure. No differences was observed in age, family history for atopy and/or asthma, clinical presentations, chest X-ray, or laboratory findings in children with HBoV alone vs. multiple viral detection. RSV was the most frequently co-detected virus (61.3%). When compared with HBoV detection alone, the co-detection of RSV and HBoV was associated with male sex (P = 0.013), younger age (P = 0.01), and lower blood neutrophil count (P = 0.032). Conclusions HBoV can be detected alone and in co-infection respiratory samples of children with an acute respiratory tract infection. A cause-effect relationship between HBoV and respiratory infection is not clear, so further studies are needed to clarify this point.the cause-effect relationship between HBoV detection and respiratory infections cannot be achieved, yet based on our data and further studies are needed to clarify if HBoV can play a pathogenetic role in respiratory diseases of children.

Background A study of respiratory syncytial virus-A (RSV A) genotype ON1 genetic variability and clinical severity in infants hospitalized with bronchiolitis over 6 epidemic seasons (2012–2013 to 2017–2018) was carried out. Methods From prospectively enrolled term infants hospitalized for bronchiolitis, samples positive for RSV A ON1 (N = 139) were sequenced in the second half of the G gene. Patients’ clinical data were obtained from medical files and each infant was assigned a clinical severity score. ANOVA comparison and adjusted multinomial logistic regression were used to evaluate clinical severity score and clinical parameters. Results The phylogenetic analysis of 54 strains showed 3 distinct clades; sequences in the last 2 seasons differed from previous seasons. The most divergent and numerous cluster of 2017–2018 strains was characterized by a novel pattern of amino acid changes, some in antigenic sites. Several amino acid changes altered predicted glycosylation sites, with acquisition of around 10 new O-glycosylation sites. Clinical severity of bronchiolitis increased in 2016–2017 and 2017–2018 and changed according to the epidemic seasons only. Conclusions Amino acid changes in the hypervariable part of G protein may have altered functions and/or changed its immunogenicity, leading to an impact on disease severity.

Background Bronchiolitis is the most common acute viral infection of the lower respiratory tract in infants. Clinical severity is associated with different risk factors; however, no clinical, laboratory, or radiological findings are able to predict the course of the disease in full‐term infants. Lung ultrasound (LUS) is a valid technique for the diagnosis and evaluation of pediatric respiratory diseases. Aims The aim of our study was to correlate an LUS score with a clinical score, to describe lung ultrasound findings in cases and controls, and to compare LUS findings with chest X‐ray (CXR) in infants hospitalized with bronchiolitis. Methods We conducted a single‐center, longitudinal, prospective study on 92 infants. Sixty‐three out of 92 infants were hospitalized for acute bronchiolitis (cases) and twenty‐nine out of 92 for diseases not involving the respiratory system (controls). All patients with bronchiolitis underwent a clinical evaluation with the assignment of a clinical severity score and performed lung ultrasound with the assignment of an LUS score. Twenty‐three out of 63 infants with bronchiolitis underwent also a CXR for clinical indications. Control infants performed only LUS. Results In infants with bronchiolitis LUS score showed a positive correlation with the clinical score (r = .62, p < .001) and the length of hospitalization (r = .42; p < .001). The need of oxygen therapy was more frequent in the patients with higher LUS score (p < .001). LUS findings observed in the cases were the presence of B‐lines, subpleural consolidations, and abnormalities of the pleural line. No LUS alterations were observed in the controls. In patients who performed LUS and CXR, we found a correlation between the presence of abnormalities of the pleural line with LUS and the presence of air trapping with CXR (r = .55; p = .007).

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