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Hypersensitivity reactions represent one of the most common causes of hesitancy for adherence to national vaccination programs. The majority of hypersensitivity reactions after vaccination are mild, and anaphylaxis is reported to be rare, although it remains challenging to estimate the frequency attributed to each single vaccine, either because of the lower number of administered doses of less common vaccines, or the administration of simultaneous vaccine in most of the vaccination programs. Although literature remains scattered, international consensus guides clinicians in identifying patients who might need the administration of vaccines in protected environments due to demonstrated hypersensitivity to vaccine components or adjuvants. Here we provide the current guidance on hypersensitivity reactions to vaccines and on vaccination of children with allergy disorders., (© 2024 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Some live vaccines, particularly Bacillus Calmette-Guérin (BCG), oral polio vaccine (OPV), and measles vaccine, can reduce the incidence of all-cause mortality by outreaching the mere control of specific infections and exerting off-target effects. Asides from the prevention of viral infection, some other vaccines, such as those against flu or rotavirus, could reduce the risk of developing autoimmunity. The nonspecific effects of vaccines are mediated by the innate immune system, mainly through the so-called trained innate immunity. These observations paved the way for developing tolerogenic and trained immunity-based vaccines with substantial implications for more effective use of vaccines and combat vaccine hesitancy., (© 2022 The Authors. Pediatric Allergy and Immunology published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Flu virus infection is a common cause of acute respiratory illness, with the major incidence in pediatric age, high morbidity, and mortality. The flu vaccine is recommended for all people aged ≥6 months, unless specific contraindications are present. Younger and older age, pregnancy, chronic diseases like asthma, and immunodeficiency are risk factors for severe complications following flu infection. Thus, these categories represent the target for flu vaccine strategies in most countries. Inactivated influenza vaccine (IIV), recombinant influenza vaccine (RIV) or live-attenuated influenza virus (LAIV) are currently available, with specific precautions and contraindications. We aim to resume the current indications for vaccines in the vulnerable populations to support flu vaccination inclusiveness, in anticipation of a "universal vaccine" strategy., (© 2020 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Background: Pollen-related seasonal allergic rhinoconjunctivitis (SAR) is a very frequent pediatric disease in Westernized countries. Risk factors and disease phenotypes have been thoroughly examined in several cross-sectional studies. By contrast, only a few studies have examined disease evolution in patient cohorts. We investigated predictive biomarkers of disease evolution in a large cohort of children with SAR., Methods: During 2015-2017 (follow-up), we re-examined 401 patients from those enrolled in 2009-2011 (baseline) by the "Panallergens in Pediatrics" study, a large multicenter survey of Italian children with SAR. Information on clinical history (standard questionnaire, AllergyCARD®; TPS, Italy) and skin prick tests for inhalant and foods extracts (ALK-Abelló, Hørsholm, Denmark) was acquired as at baseline visit. Evolution in clinical and sensitization data of patients was analyzed over time, as well as their association with the main baseline characteristics and atopy risk factors., Results: The average age of participants was 10.4 ± 3.4 years at baseline and 16.2 ± 3.6 years at follow-up. SAR persisted in 93.3% of patients at follow-up and became more frequently associated with asthma (from 36.7% at baseline to 48.6% at follow-up) and oral allergy syndrome (OAS, from 23.4% to 37.7%). Compared to baseline, the prevalence of skin sensitization to some pollens (Phleum pratense, Corylus avellana, Platanus acerifolia, Artemisia vulgaris) and vegetables (hazelnut, wheat, and apple) significantly decreased at follow-up. Earlier onset of SAR and polysensitization at baseline were associated with incident asthma at follow-up. The presence at baseline of serum IgE to the following allergen molecules was identified as biomarkers of clinical evolution: (a) Phl p 1, for persistence of SAR; (b) Phl p 5, for persistence of both rhinitis and asthma; (c) Pru p 3, for new onset of asthma; (d) Bet v 1, for persistence of OAS., Conclusions: Seasonal allergic rhinoconjunctivitis is clinically heterogeneous in its evolution from childhood to adolescence. The detection of serum IgE to specific molecules (Phl p 1, Phl p 5, Bet v 1, Pru p 3) may be useful as biomarkers to predict SAR persistence and future onset of comorbidities, such as asthma and/or OAS., (© 2019 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Background: Schoolchildren screening for allergic diseases may improve early identification and management of atopic children. The aim of this study was to perform a schoolchildren screening program for identification of children with allergic diseases., Methods: All parents of children attending to 13 primary schools in the city of Rome were requested to fill in a demographic data form and the ChAt questionnaire. Allergological evaluation was performed in the children with suspect of allergy (ChAt score > 2). Ocular examination was performed to identify signs of allergic conjunctivitis. The presence of allergic symptoms was related to demographic and environmental variables., Results: A total of 2667 children (mean age: 7.1 ± 1 years) were included, and 2489 (93.3%) parents completed the ChAt questionnaire. Results of ChAt questionnaire showed a previous diagnosis of allergic disease in 637 (25.6%) children and the potential presence of an allergic disease (ChAt score > 2) in 35.1%. Multivariate analysis showed that older age, male gender, and having less than two siblings were associated with higher risk of allergic disease. Visual screening showed the presence of clinical signs of allergic conjunctivitis in 2% of children. Allergologic evaluation in 334 children confirmed the diagnosis of allergic disease in 324 (97%) cases. Among them, 97 (29.9%) did not refer to a previous formal diagnosis of allergic condition., Conclusions: This study confirmed that schoolchildren screening using ChAt questionnaire could represent a useful tool for early identification of yet undiagnosed atopic children., (© 2019 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Background: Pollen-induced allergic rhinoconjunctivitis (AR) is highly prevalent and rapidly evolving during childhood. General practitioners may not be fully aware of the nature and severity of symptoms experienced by patients and might underestimate the prevalence of moderate or severe disease. Thus, the relevance of early diagnosis and intervention may be overlooked., Objectives: To investigate the severity of pollen-induced AR and its determinants in Italian children referred to allergy specialists and who had never received specific immunotherapy (SIT)., Methods: Children (age 4-18 yr) affected by pollen-induced AR who had never undergone SIT were recruited between May 2009 and June 2011 in 16 pediatric outpatient clinics in 14 Italian cities. Recruited children's parents answered standardized questionnaires on atopic diseases (International Study of Allergy and Asthma in Childhood, Allergic Rhinitis and its Impact on Asthma, Global Initiative for Asthma). The children underwent skin-prick test (SPT) with several airborne allergens and six food allergens. Information on socio-demographic factors, parental history of allergic diseases, education, perinatal events, breastfeeding, nutrition and environmental exposure in early life was collected through an informatics platform shared by the whole network of clinical centers (AllergyCARD™)., Results: Among the 1360 recruited patients (68% males, age 10.5 ± 3.4 yr), 695 (51%) had moderate-to-severe AR, 533 (39%) asthma, and 325 (23.9%) oral allergy syndrome (OAS). Reported onset of pollen-induced AR was on average at 5.3 ± 2.8 yr, and its mean duration from onset was 5.2 ± 3.3 yr. Only 6.2% of the patients were pollen-monosensitized, and 84.9% were sensitized to ≥3 pollens. A longer AR duration was significantly associated with moderate-to-severe AR symptoms (p 0.004), asthma (p 0.030), and OAS comorbidities (p < 0.001)., Conclusions: This nationwide study may raise awareness of the severity of pollen-induced AR among Italian children who have never received pollen SIT. The strong association between pollen-induced AR duration and several markers of disease severity needs replication in longitudinal studies, while suggesting that countrywide initiatives for earlier diagnosis and intervention should be planned., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Recurrent infections are a common cause of morbidity in childhood. Several reports have associated this condition to low levels of IgA and IgG subclasses and/or lack of specific antipolysaccharide antibody response, although the relevance of these defects in terms of prognosis and therapeutic approach is still unclear. The aim of our study was to determine the frequency and the clinical relevance of humoral immunodeficiency (HID) other than hypogammaglobulinemia in children affected by recurrent infections. We recruited 67 pediatric patients affected by recurrent infections. Serum IgG, IgA, IgM, IgG2, IgG3, and specific anti-Haemophilus influenzae (anti-Hib) antibodies were determined. Thirty-seven out of 67 patients showed antibody defects (55%). IgA deficiency was observed in 21 out of 67 patients (31%), followed by IgG2 (18%), IgG3 (15%) and IgM (6%) defects. Anti-Hib deficiency was present in three out of 44 patients (7%). A tendency for a higher occurrence of pneumonia and otitis, although not statistically significant (p > 0.05), was observed in HID patients compared to children with normal humoral function. No statistical difference as to the frequency of mild infections (URI) was found between HID and non-HID patients. We therefore suggest that the therapeutic program is based on the clinical status of the patients. Long-term follow-up with repeated determinations of antibody levels is crucial, however, to detect those defects that might evolve into more complex immunodeficiencies.