The SARS-CoV-2 vaccine roll-out has been successful around the world. However, there are increasing concerns about adverse events. We report two pediatric cases of Multisystem-Inflammatory-Syndrome (MIS-C) with neurological involvement that occurred after SARS-CoV-2 vaccination and unknown recent SARS-CoV-2 infection. Brain magnetic resonance revealed mild-encephalopathy with reversible-splenial-lesion in both cases and complete resolution within 4 weeks. In conclusion, this report aims to describe rare emerging clinical entities that can help pediatricians to make an early diagnosis and to provide appropriate treatment. Multisystem-Inflammatory-Syndromes following COVID-19 vaccination remain rare events. When a history of a recent contact with SARS-CoV-2 is present, a careful evaluation by the clinicians in charge of immunization activities is suggested prior to proceeding with the vaccination.

Varicella pneumonia has been studied extensively in adults; it may also affect children and may require hospitalization. We examined pneumonia complications in children hospitalized for varicella, over a 13 year period. Pneumonia occurred in 8.2% of children hospitalized for varicella. The median length of hospitalization was 6 days. No statistically significant difference in length of stay was detected between immunodepressed children and previously healthy children. The hospitalization was on average shorter in patients who started antiviral therapy within 24 h of varicella onset. None of the included patients had been previously immunized for varicella. Our results support the need for increased awareness of current varicella prevention recommendations among both immunocompetent and immunodepressed individuals. In children affected by varicella, prompt antiviral therapy may be indicated to reduce the number of days of hospitalization.

Meningococcal meningitis (MM) is known to be responsible of high cost for the Public Health Administration. Aim of the work is to calculate the costs for the hospitalization of pediatric patients affected by MM. We calculate the costs for the hospitalization of pediatric patients affected by MM in the acute phase (HAP) over a nine year period. We performed a MEDLINE search to verify the cost of MM HAP reported in other studies. At Bambino Gesù Children Hospital, the median cost of HAP was of 12,604 euro (range from 9203 to 35,050 euro). Comparing our data with the previous studies, we find out similar results of approximately 16,750 euro (range 12,000–20,000 euro). Despite the relative rarety of the disease, MM is associated to direct high cost of HAP. Hospital costs are an important end-point in health economic evaluation of the disease and may be useful to policy makers and health economists to understand the potential benefit of improving meningococcal vaccination programmes.

Human cytomegalovirus (CMV) is a common herpesvirus causing lifelong latent infection in most people and is a primary cause of congenital infection worldwide. Given the role of NK cells in the materno-fetal barrier, we investigated peripheral blood NK cell behavior in the context of CMV infection acquired during pregnancy. We analyzed the NK phenotype and CD107a surface mobilization on PBMCs from CMV-transmitting and non-transmitting mothers and newborns with or without congenital infection. NK cells from non-transmitting mothers showed the typical phenotype of CMV-adaptive NK cells, characterized by higher levels of NKG2C, CD57, and KIRs, with reduced NKG2A, compared to transmitting ones. A significantly higher percentage of DNAM-1+, PD-1+, and KIR+NKG2A-CD57+PD-1+ CD56dim cells was found in the non-transmitting group. Accordingly, NK cells from congenital-CMV (cCMV)-infected newborns expressed higher levels of NKG2C and CD57, with reduced NKG2A, compared to non-congenital ones. Furthermore, they showed a significant expansion of CD56dim cells co-expressing NKG2C and CD57 or with a memory-like (KIR+NKG2A-CD57+NKG2C+) phenotype, as well as a significant reduction of the CD57-NKG2C- population. Degranulation assays showed a slightly higher CD107a geomean ratio in NK cells of mothers who were non-transmitting compared to those transmitting the virus. Our findings demonstrate that both CMV-transmitting mothers and cCMV newborns show a specific NK profile. These data can guide studies on predicting virus transmission from mothers and congenital infection in infants.

Early-life immune development is a critical factor in predicting the risk of childhood respiratory infections, asthma, and poor vaccine responses. Identifying immune endotypes that predispose children to these conditions could lead to the development of predictive biomarkers and early interventions, potentially improving long-term health outcomes. The IDEaL (Immune Development in Early Life)-Rome prospective pediatric cohort, based at Children's Hospital Bambino Gesù (Rome, Italy), is part of a National Institutes of Health/National Institute of Allergy and Infectious Diseases-supported longitudinal observational study. To identify molecular biomarkers associated with increased susceptibility to respiratory infections, asthma, and poor vaccine responsiveness in early childhood. The study aims to establish predictive immune profiles that could guide interventions to redirect harmful immune trajectories. Mothers are approached during pregnancy prospectively and eligible infants are enrolled at delivery. The study includes 6 planned visits up to 5 years of age. Biosamples (blood, stool, nasal swabs, and cord blood for a subset) were collected at each visit for multiomic data (cytokines, proteomics, microbiome), alongside clinical data on vaccination, infections, and wheezing. The study included 273 participants (100% enrollment completion rate). Over 2 years, clinical and multiomic data were integrated to investigate immune trajectories related to clinical outcomes. Specific data on the outcomes will be provided in future reports as longitudinal analysis continues. The IDEaL-Rome cohort study seeks to identify biomarkers predicting immune development trajectories. These findings could enable early interventions to redirect harmful immune trajectories in infancy and improve health outcomes, though further studies are required to validate biomarkers and refine predictive models for clinical application.

Background: Varicella is a common pediatric infection. Even if it generally has a benign course, it may complicate and require hospitalization. The aim of our study was to estimate the acute hospitalization cost (AHC) for varicella in the acute phase in a pediatric population. Methods: We calculated the AHC of pediatric patients admitted for varicella at Bambino Gesù Children Hospital, Rome, Italy, from 1 November 2005 to 1 November 2020. Results: In the study period, 825 pediatric patients affected by varicella were hospitalized. The mean hospitalization cost was EUR 4015.35 (range from EUR 558.44 to EUR 42,608.00). Among patients, 55% were unvaccinable due to either their age or their immunosuppression status. They would benefit from herd immunity, reducing the overall AHC by EUR 182,196,506. Since the introduction of the compulsory vaccination against varicella in Italy, we observed a significant reduction in AHC cost of 60.6% in 2019 and of 93.5% in 2020. Finally, from the beginning of the COVID-19 pandemic, we documented a decline of 81.2% and 76.9% in varicella hospitalization, compared to 2018 and 2019, respectively. Conclusions: Varicella AHC is an important economic and health assessment point and can be useful for improving preventive strategies.