BackgroundDuration of humoral and cellular memory in children previously infected SARS-CoV-2 or vaccinated and subsequent risk of reinfection is still not fully elucidated.MethodsSystematic review of studies retrieved from medical databases and article reference lists.ResultsFrom 2420 identified articles, 24 met the inclusion criteria. Children infected during the pre-omicron era developed long lasting (at least 10-12 months) humoral and cellular immunity against pre-Omicron SARS-CoV-2 variants, but have reduced in vitro cross-reactivity against Omicron. Conversely, although vaccination has a limited efficacy in preventing new infection with pre-Omicron and Omicron variants, in vitro studies suggested that vaccine-induced immunity provides better in vitro cross-neutralization against pre-Omicron and Omicron variants. Preprints published after the period of inclusion of our review suggested that overall risk of infection after Omicron infection is reduced, but children developed weak neutralizing responses in about half cases.ConclusionsAvailable evidence, although limited, suggested a long-lasting but unperfect protection of previous infections or vaccination against pre-Omicron and Omicron variants. Based on our findings, it might be reasonable to offer families of children infected before Omicron a booster vaccination. A similar indication should be proposed also for those infected with Omicron, specifically for more fragile children at higher risk of COVID-19-related complications, based on better cross-variant neutralisation induced by vaccination.Systematic review registrationPROSPERO, identifier ID 353189.

Asthma is the most common chronic disease in childhood. Overweight and obesity are included among the comorbidities considered in patients with difficult-to-treat asthma, suggesting a specific phenotype of the disease. Therefore, the constant increase in obesity prevalence in children and adolescents raises concerns about the parallel increase of obesity-associated asthma. The possible correlation between obesity and asthma has been investigated over the last decade by different authors, who suggest a complex multifactorial relationship. Although the particular non-eosinophilic endotype of obesity-related asthma supports the concept that high body weight precedes asthma development, there is ongoing debate about the direct causality of these two entities. A number of mechanisms may be involved in asthma in combination with obesity disease in children, including reduced physical activity, abnormal ventilation, chronic systemic inflammation, hormonal influences, genetics and additional comorbidities, such as gastroesophageal reflux and dysfunctional breathing. The identification of the obesity-related asthma phenotype is crucial to initiate specific therapeutic management. Besides the cornerstones of asthma treatment, lifestyle should be optimized, with interventions aiming to promote physical exercise, healthy diet, and comorbidities. Future studies should clarify the exact association between asthma and obesity and the mechanisms underlying the pathogenesis of these two related conditions with the aim to define personalized therapeutic strategies for asthma management in this population.

Incidence of inflammatory bowel diseases (IBDs), including Crohn’s disease (CD) and ulcerative colitis (UC), is increasing worldwide. Children with IBDs have a dysfunctional immune system and they are frequently treated with immunomodulating drugs and biological therapy, which significantly impair immune system functions and lead to an increased risk of infections. Vaccines are essential to prevent at least part of these infections and this explains why strict compliance to the immunization guidelines specifically prepared for IBD patients is strongly recommended. However, several factors might lead to insufficient immunization. In this paper, present knowledge on the use of vaccines in children with IBDs is discussed. Literature review showed that despite a lack of detailed quantification of the risk of infections in children with IBDs, these children might have infections more frequently than age-matched healthy subjects, and at least in some cases, these infections might be even more severe. Fortunately, most of these infections could be prevented when recommended schedules of immunization are carefully followed. Vaccines given to children with IBDs generally have adequate immunogenicity and safety. Attention must be paid to live attenuated vaccines that can be administered only to children without or with mild immune system function impairment. Vaccination of their caregivers is also recommended. Unfortunately, compliance to these recommendations is generally low and multidisciplinary educational programs to improve vaccination coverage must be planned, in order to protect children with IBD from vaccine-preventable diseases.

No abstract