Background Anaphylaxis, which is rare, has been reported after COVID‐19 vaccination, but its management is not standardized. Method Members of the European Network for Drug Allergy and the European Academy of Allergy and Clinical Immunology interested in drug allergy participated in an online questionnaire on pre‐vaccination screening and management of allergic reactions to COVID‐19 vaccines, and literature was analysed. Results No death due to anaphylaxis to COVID‐19 vaccines has been confirmed in scientific literature. Potential allergens, polyethylene glycol (PEG), polysorbate and tromethamine are excipients. The authors propose allergy evaluation of persons with the following histories: 1—anaphylaxis to injectable drug or vaccine containing PEG or derivatives; 2—anaphylaxis to oral/topical PEG containing products; 3—recurrent anaphylaxis of unknown cause; 4—suspected or confirmed allergy to any mRNA vaccine; and 5—confirmed allergy to PEG or derivatives. We recommend a prick‐to‐prick skin test with the left‐over solution in the suspected vaccine vial to avoid waste. Prick test panel should include PEG 4000 or 3500, PEG 2000 and polysorbate 80. The value of in vitro test is arguable. Conclusions These recommendations will lead to a better knowledge of the management and mechanisms involved in anaphylaxis to COVID‐19 vaccines and enable more people with history of allergy to be vaccinated.

Background:Anaphylaxis is increasing at pediatric age; however, its characterization is hampered by underdiagnosis and underreporting. The aim of this study was to identify the causes of anaphylaxis in children and adolescents in Portugal, thus contributing to a better knowledge of its etiology, clinical manifestations, and management.Methods: During a 10-year period, a nationwide notification system for anaphylaxis was implemented, with voluntary reporting by allergists. Data on 533 patients under 18 years of age with anaphylaxis were included.Results: Mean age was 8.5 ± 4.9 years, 61% were male; 45% had asthma. Mean age at the first anaphylaxis episode was 5.3 ± 4.7 years (ranging from 1 month to 17 years of age), 63% at pre-school age. Most reactions occurred at home (57%). Food-induced anaphylaxis was the leading cause (77%). The main culprit foods were cow's milk (32%), tree nuts (16%), shellfish (13%), egg (12%), fresh fruits (11%), fish (8%), and peanut (8%). Other causes included drugs (11%), insect sting (5%), cold-induced anaphylaxis (4%), exercise-induced anaphylaxis (2%), latex (1%), and idiopathic anaphylaxis (1%). Most patients (83%) were admitted to the emergency department; only 46% received adrenaline treatment. Recurrence of anaphylaxis occurred in 41% of the patients (3 or more episodes in 21%). An adrenaline autoinjector was used in 9% of the patients. Conclusions:In the Portuguese pediatric population, food is the leading cause of anaphylaxis. Undertreatment with adrenaline and high recurrence of anaphylaxis highlight the need to improve both the diagnosis and the therapeutic management of this life-threatening entity.

Background: Nonsteroidal anti-inflammatory drugs (NSAIDS) are among the most common causes of drug hypersensitivity (HS) reactions. The diagnosis is based on a careful clinical history, and provocation tests are considered the gold standard for diagnosis. Skin tests have some value to study reactions to pyrazolones. Laboratory investigations are mostly used for research purposes. Different phenotypes have been described. Objective and Methods: Our aim was to describe the most common clinical manifestations of NSAID HS in a large population of adult patients, the drugs involved, the association with previously described risk factors, and the outcome of diagnostic procedures. The classification of reactions proposed by the European Academy of Allergy and Clinical Immunology (EAACI) Drug Allergy Interest Group was adopted. Results: Acetylsalicylic acid was the drug most often involved in reactions (34%), isolated cutaneous symptoms were the most reported (60%), and immediate reactions (58%) were the most common. There was an overall female predominance (64%) and 35% of the patients were atopic. HS to NSAIDs was confirmed in 21% of the patients. The most common phenotypes encountered among HS patients were NSAID-induced urticaria/angioedema and single-NSAID-induced urticaria/angioedema or anaphylaxis. Logistic regression analysis showed that gender and atopy were not significant risk factors for HS confirmation, but diagnosis depended on the number of previous reactions, the type of reaction, and the time interval between drug intake and reaction. Conclusion: Only 21% of suspected HS reactions were confirmed after diagnostic workup. Patients describing >1 previous reaction and suffering immediate reactions had a higher probability of a positive investigation.

Gastric carcinoma (GC) represents the most common cause of death in patients with common variable immunodeficiency (CVID). However, a limited number of cases have been characterised so far. In this study, we analysed the clinical features, bacterial/viral infections, detailed morphology and immune microenvironment of nine CVID patients with GC. The study of the immune microenvironment included automated digital counts of CD20+, CD4+, CD8+, FOXP3+, GATA3+ and CD138+ immune cells, as well as the evaluation of PD-L1 expression. Twenty-one GCs from non-CVID patients were used as a control group. GC in CVID patients was diagnosed mostly at early-stage (n = 6/9; 66.7%) and at younger age (median-age: 43y), when compared to non-CVID patients (p < 0.001). GC pathogenesis was closely related to Helicobacter pylori infection (n = 8/9; 88.9%), but not to Epstein-Barr virus (0.0%) or cytomegalovirus infection (0.0%). Non-neoplastic mucosa (non-NM) in CVID-patients displayed prominent lymphocytic gastritis (100%) and a dysfunctional immune microenvironment, characterised by higher rates of CD4+/CD8+/Foxp3+/GATA3+/PD-L1+ immune cells and the expected paucity of CD20+ B-lymphocytes and CD138+ plasma cells, when compared to non-CVID patients (p < 0.05). Changes in the immune microenvironment between non-NM and GC were not equivalent in CVID and non-CVID patients, reflecting the relevance of immune dysfunction for gastric carcinogenesis and GC progression in the CVID population.

The first reports of hypersensitivity reactions following the rollout of COVID-19 vaccination programs have raised public concern. Given the recent availability and novel mechanisms of COVID-19 vaccines, there is limited data on possible hypersensitivity reactions. Although it seems rare, the incidence of anaphylaxis for approved COVID-19 vaccines has been suggested as being higher when compared to previous vaccines. Adequate risk assessment, recognition, classification, and management of hypersensitivity reactions is crucial to ensure safe immunization and avoid misinformation and vaccine hesitancy. In this review, we present an overview of the types of hypersensitivity reactions that can potentially occur due to vaccination and the possible allergenic components of COVID-19 vaccines, as well as a suggestion for causality and risk assessment for the BNT162b2, mRNA-1273 and AZD1222 vaccines.