Vaccine allergy

Overdiagnosis of vaccine allergy: Skin testing and challenge at a public specialized unit (CRIE) in Rio de Janeiro, Brazil

Background

Vaccination is an extremely safe public health intervention, but rare IgE-mediated adverse events must be identified to avoid the risk of anaphylaxis in the event of reexposure. However, using only clinical history to diagnose previous allergic reactions may lead to overdiagnosis of vaccine allergy and even to the use of medical exemptions as a subterfuge to mandatory vaccination.

Methods

We conducted a retrospective study to describe the outcomes of patients with a history of vaccine or vaccine component allergy who were evaluated at our unit from 2011 to 2017. Data on allergy history, skin test results, vaccines prescribed, and adverse events were retrieved from the medical records at the Centro de Referência para Imunobiológicos Especiais (Reference Center of Special Immunobiologicals)-Fiocruz, in Rio de Janeiro, Brazil.

Results

Of 34 adults with history of allergy to vaccine or vaccine components, 32 (94.1%) were successfully vaccinated without serious adverse events after our evaluation. In 12 patients (35%), the time elapsed between the allergy symptoms and evaluation in the Centro de Referência para Imunobiológicos Especiais-Fiocruz was more than 10 years.

Conclusion

Specialized care and use of skin tests allowed safe vaccination of the majority of patients. An objective, systematic evaluation of a history of vaccine allergy can prevent its improper use to avoid mandatory vaccination and reduce missed opportunities for immunization.

Application of Baculovirus Expression Vector System (BEVS) in Vaccine Development

Vaccination is one of the most effective strategies to control epidemics. With the deepening of people's awareness of vaccination, there is a high demand for vaccination. Hence, a flexible, rapid, and cost-effective vaccine platform is urgently needed. The baculovirus expression vector system (BEVS) has emerged as a promising technology for vaccine production due to its high safety, rapid production, flexible product design, and scalability. In this review, we introduced the development history of BEVS and the procedures for preparing recombinant protein vaccines using the BEVS platform and summarized the features and limitations of this platform. Furthermore, we highlighted the progress of the BEVS platform-related research, especially in the field of vaccine. Finally, we provided a new prospect for BEVS in future vaccine manufacturing, which may pave the way for future BEVS-derived vaccine development.

Increasing the COVID-19 immunization rate through allergy testing

BACKGROUND

Vaccination of the population is required to combat the COVID-19 pandemic. Allergy testing could reduce anxiety towards COVID-19 vaccination and thereby may increase vaccination rate, however, its effectiveness remains unclear.

METHODS

One hundred and thirty prospective real-life patients in need of but not daring to get vaccinated asked for allergy workup for COVID-19 vaccine hypersensitivity in 2021/2022. Characterization of patients, identification of anxieties, decrease of patient's anxiety levels, overall vaccination rate and adverse reactions after vaccination were assessed.

RESULTS

Tested patients were characterized by being female (91.5%) and having a high rate of previous allergies (e.g. to food 55.4%, drugs 54.6%, or previous vaccinations 50%) and dermatological disease (29.2%) but not always had medical contraindications for COVID-19 vaccination. Sixty one patients (49.6%) were highly concerned (4-6, Likert scale 0-6) about vaccination and 47 (37.6%) expressed resolving thoughts about vaccinaion anaphylaxis (3-6, Likert scale 0-6). However only 35 patients (28.5%) were scared of getting COVID-19 within 2 months (4-6, Likert scale 0-6) and only 11 (9%) patients had high expectations of getting COVID-19 (4-6, Likert scale 0-6). Allergy testing significantly (p < 0.01 to p < 0.05 respectively) reduced the median anxiety of allergic symptoms following vaccination: dyspnoea (4.2-3.1), to faint (3.7-2.7), long-term consequences (3.6-2.2), pruritus (3.4-2.6), skin rash (3.3-2.6) and death (3.2-2.6). After allergy testing, most patients (108/122, 88.5%) let themselves be vaccinated within 60 days. Revaccinated patients with previous symptoms experienced a reduction of symptoms (p < 0.05) upon revaccination.

CONCLUSIONS

Patients not daring to get vaccinated have more anxiety towards vaccination than to acquire COVID-19. For those, allergy testing excludes vaccine allergy, and is a tool to increase vaccination willingness and thereby helps to combat vaccination hesitancy.

Histopathological Patterns of Cutaneous Adverse Reaction to Anti-SARS-CoV-2 Vaccines: The Integrative Role of Skin Biopsy

The advent of vaccines represented a milestone to allow the slowing down and then containing of the exponential increase in ongoing infections and deaths of COVID-19. Since the first months of the vaccination campaign in various continents, there has been a certain number of reports of adverse events, including skin reactions. We conducted a systematic review, searching on PubMed, Web of Science, Scopus, and Cochrane Library for the words: COVID vaccine, dermatopathology, skin, eruptions, rash, cutaneous, BNT162b2 (Pfizer-BioNTech), ChAdOX1 (AstraZeneca), and mRNA-1273 (Moderna). A total of 28 records were initially identified in the literature search of which two were duplicates. After screening for eligibility and inclusion criteria, 18 publications were ultimately included. Various clinical cutaneous manifestations and histopathological patterns following vaccination have been described in literature. The most frequent clinical-pathological presentations were erythematous maculo-papular eruptions in different way of distribution with histopathological pictures mostly represented by interface changes and mixed peri-vascular and peri-adnexal cell infiltrate. Other presentations included new onset of pemphigoid bullous disease (n = 15), delayed T-cell-mediated hypersensitivity reaction (injection site reactions) (n = 10), purpuric skin rash (n = 13), mostly localized on the legs bilaterally and symmetrically with histological pictures characterized by extravasation of erythrocytes in the superficial and middle dermis, and other types of reactions. New studies with large case series and further literature reviews are needed to improve the clinical management of patients and optimize the timeline for carrying out histological biopsy for confirmatory, supportive, and differential diagnosis purposes.

Allergic adverse events following immunization: Data from post-marketing surveillance in Apulia region (South of Italy)

Introduction

Among adverse events following immunization (AEFIs), allergic reactions elicit the most concern, as they are often unpredictable and can be life-threatening. Their estimates range from one in 1,000,000 to one in 50,000 vaccine doses. This report describes allergic events following immunization reported from 2020 to 2021 in Puglia, a region in the South-East of Italy with around 4 million inhabitants. Its main objective is to describe the allergic safety profile of currently employed vaccines.

Materials and methods

This is a retrospective observational study. The study period spanned from January 2020 to December 2021, and the whole Apulian population was included in the study. Information regarding AEFIs reported in Puglia during the study period was gathered from the Italian Drug Authority's pharmacovigilance database (National Pharmacovigilance Network, RNF). The overall number of vaccine doses administered was extrapolated by the Apulian online immunization database (GIAVA). Reporting rates were calculated as AEFIs reported during a certain time span/number of vaccine doses administered during the same period.

Results

10,834,913 vaccine doses were administered during the study period and 95 reports of allergic AEFIs were submitted to the RNF (reporting rate 0.88/100,000 doses). 27.4% of the reported events (26/95) were classified as serious (reporting rate 0.24/100,000 doses). 68 out of 95 (71.6%) adverse events were at least partially resolved by the time of reporting and none of them resulted in the subject's death.

Conclusions

Allergic reactions following vaccination were rare events, thus confirming the favourable risks/benefits ratio for currently marketed vaccines.

Case series of chronic spontaneous urticaria following COVID-19 vaccines: an unusual skin manifestation

BACKGROUND

Urticaria following the COVID-19 vaccine was rarely reported and had a short self-limited resolution. However, there has been relatively little literature published on CSU induced by COVID-19 vaccines.

PURPOSE

We describe a case series of patients who experienced CSU after SARS-CoV-2 vaccination.

METHODS

A retrospective case series of 10 patients referred to the Department of Clinical Pharmacology of the University of Monastir (January 2021-January 2022) and included for evaluation of urticaria after COVID-19 vaccination.

RESULTS

The median age was 31 years and patients were mostly female. Atopy was presented in 3 patients and urticaria was accompanied by angioedema in 6 patients. The median time interval between vaccination and the onset of urticaria was 28.5 h. The offended dose was the first one in 8 patients. The resolution of the eruption was observed at least 2 months later, despite the regular use of a full dose of antihistamine in nine patients. Polynuclear leucocytosis was identified in 5 patients. Anti-TPOAb was positive in one patient after receiving the BNT162b2 vaccine. Total serum IgE was elevated in 4 patients. Skin tests for the suspected vaccine as well as the vaccine excipient were negative.

CONCLUSION

We add to the medical literature ten new cases of chronic spontaneous urticarial reactions following COVID-19 vaccines uncontrolled with high-dose first-generation H1 antihistamines.

Adverse events following administration of COVID-19 vaccines in Saudi Arabia

Previous studies investigated the frequency of different adverse events of COVID-19 vaccines. However, this study compares these adverse events between the two main COVID-19 vaccines used in Saudi Arabia (Pfizer-BioNTech and Oxford-AstraZeneca) using telemedicine technology. A cross-sectional study was conducted among 958 individuals, 7 days after receiving either Pfizer-BioNTech or Oxford-AstraZeneca vaccines during June 2021. Immediate adverse events were reported by 1.04% and 2.09% for Pfizer-BioNTech and Oxford-AstraZeneca vaccines, respectively, with no serious events. Recipients of Pfizer-BioNTech vaccine had a higher percentage of local adverse events (24.8% versus 9.8% in AstraZeneca vaccine). The most common reported systemic adverse events in both vaccines respectively were general fatigue (23.1% and 25.1%), fever (18.5% and 27.2%), myalgia (20.6% and 20.3%), and headache (15.2% and 17.2%). No significant difference was recorded between both vaccines regarding overall systemic adverse events; however, they were more frequent following the first dose of AstraZeneca vaccine compared to Pfizer-BioNTech vaccine, while the reverse was observed for the second dose. Adverse events were more frequent in females and younger age groups for both vaccines. Most of systemic and local adverse events were mild in nature. Further cohort studies are recommended to investigate the long-term adverse events of COVID-19 vaccines.

Allergic reactions to COVID-19 vaccines: statement of the Belgian Society for Allergy and Clinical Immunology (BelSACI)

Vaccination against COVID-19 constitutes a huge hope and a major challenge. For the first time in modern history, a global vaccination campaign has started worldwide in a short period of time and with products that were recently developed. Consequently, legitimate concerns regarding the safety and tolerability of COVID-19 vaccines arise.In line with international allergy societies, the Belgian Society for Allergy and Clinical Immunology (BelSACI) provides this statement to guide health care providers (general practitioners, specialists including allergists) and stakeholders.In this statement, we first review current evidence on allergic reactions to vaccines and the potential risk factors that have been identified.Second, we provide a risk stratification method that may be used as a worksheet during the vaccination campaign.Finally, we discuss the management of suspected or confirmed allergic reactions following vaccination.

Immediate Hypersensitivity Reactions Induced by COVID-19 Vaccines: Current Trends, Potential Mechanisms and Prevention Strategies

As the world deals with the COVID-19 pandemic, vaccination remains vital to successfully end this crisis. However, COVID-19-vaccine-induced immediate hypersensitivity reactions presenting with potentially life-threatening systemic anaphylactic reactions are one of the reasons for vaccine hesitancy. Recent studies have suggested that different mechanisms, including IgE-mediated and non-IgE-mediated mast cell activation, may be involved in immediate hypersensitivity. The main culprits triggering hypersensitivity reactions have been suggested to be the excipients of vaccines, including polyethylene glycol and polysorbate 80. Patients with a history of allergic reactions to drugs, foods, or other vaccines may have an increased risk of hypersensitivity reactions to COVID-19 vaccines. Various strategies have been suggested to prevent hypersensitivity reactions, including performing skin tests or in vitro tests before vaccination, administering different vaccines for the primary and following boosters, changing the fractionated doses, or pretreating the anti-IgE antibody. This review discusses the current trends, potential mechanisms, and prevention strategies for COVID-19-vaccine-induced immediate hypersensitivity reactions.

Delayed urticaria after BNT162b2 booster vaccination at previous intradermal test site with severe acute respiratory syndrome-coronavirus-2 spike protein

Urticaria is a common cutaneous adverse event from coronavirus disease 2019 vaccination. Previous studies hypothesized that excipients as polyethylene glycol in BNT162b2 vaccine and polysorbate in ChAdOx1 nCoV-19 vaccine are allergens. A 28-year-old woman had urticaria after a booster vaccination with BNT162b2 at the site of previous intradermal injection with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) spike protein. This reaction emphasized that delayed urticaria may not be an allergic reaction to excipient but rather to the immunogen as such as SARS-CoV-2 spike protein.

COVID-19 Vaccine Anaphylaxis: Current Evidence and Future Approaches

Vaccine anaphylaxis is rare; however, severe allergic reactions after administration of a coronavirus disease 2019 (COVID-19) vaccines have been reported. Excipients in the vaccine may play a role in severe allergic reactions post-vaccination. Various mechanisms, including IgE-mediated pathways, direct mass cell stimulation via the Mas-related G protein-coupled receptor-X2, and complement pathway activation, have been proposed to cause the anaphylaxis. Skin testing, using the basophil activation test, has been used to clarify the mechanism of the anaphylaxis and provide safety information for the next injection. Here, we review the current evidence and suggested approaches for patients who experienced an immediate severe allergic reaction to the first dose of a COVID-19 vaccine.

Cutaneous Adverse Reactions Associated with SARS-CoV-2 Vaccines

Many patients are receiving SARS-CoV-2 vaccinations, which have been associated with a variety of adverse effects. Cutaneous adverse reactions to SARS-CoV-2 vaccinations have been progressively reported, but they have not been reviewed according to their morphological clinical patterns. The objective of this review was to summarize the existing data concerning the cutaneous adverse reactions following SARS-CoV-2 vaccines and group them according to common morphological and pathogenetic patterns. We reviewed the English language literature up to 15 August 2021, using predefined keywords to identify the relevant studies evaluating cutaneous adverse reactions associated with SARS-CoV-2 vaccines. We search for recurrent morphological patterns sharing clinical signs and symptoms and physio-pathological mechanisms. Timing to onset following the first or booster dose of the vaccine, predisposing conditions, therapeutic management, and outcome were also collected. Among the dermatological manifestations associated with SARS-CoV-2 vaccinations, we distinguished: (1) new onset reactions and (2) flares of preexisting dermatoses. The most common were injection site reactions, affecting 30–70% and generally mild or moderate. Small case series or single case reports included filler reactions, exanthemas, vascular lesions, urticaria, eczematous dermatitis, autoimmune bullous reactions, and severe cutaneous adverse reactions. In addition, the exacerbation of chronic immuno-mediated dermatoses (mainly psoriasis and atopic dermatitis) and reactivations of herpes infection were reported. The cutaneous reactions were generally mild, self-limiting, and resembled common cutaneous drug eruptions and/or COVID-19 skin manifestations.

Rare cutaneous manifestation of COVID-19 infection and Pfizer-BioNTech COVID-19 vaccine with a unique pattern similarity

In December 2019, a new emerging virus causing mild-to-severe pneumonia was detected in China. The virus was described as a variant of SARS-CoV and was called SARS-CoV-2, then declared a pandemic by the WHO on 11 March 2020. Millions of people contracted the virus and presented with a symptomatology of variable severity, including upper respiratory tract symptoms, systemic symptoms and diarrhea. We herein report a rare skin presentation in a 33-year-old female that occurred both during COVID-19 infection and after receiving the first dose of COVID-19 vaccine.

COVID-19 vaccination and allergen immunotherapy (AIT) - A position paper of the German Society for Applied Allergology (AeDA) and the German Society for Allergology and Clinical Immunology (DGAKI)

Background: Vaccinations against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) are intended to induce an immune response to protect against infection/disease. Allergen immunotherapy (AIT) is thought to induce a (different) immune response, e.g., to induce tolerance to allergens. In this position paper we clarify how to use AIT in temporal relation to COVID-19 vaccination. Four SARS-CoV-2 vaccines are currently approved in the EU, and their possible immunological interactions with AIT are described together with practical recommendations for use. Materials and methods: Based on the internationally published literature, this position paper provides specific recommendations for the use of AIT in temporal relation to a SARS-CoV-2 vaccination. Results: AIT is used in 1) allergic rhinitis, 2) allergic bronchial asthma, 3) insect venom allergy, 4) food allergy (peanut). Conclusion: For the continuation of an ongoing AIT, we recommend an interval of 1 week before and after vaccination for subcutaneous immunotherapy (SCIT). For sublingual immunotherapy (SLIT) and oral immunotherapy (OIT), we recommend taking them up to the day before vaccination and a break of 2 – 7 days after vaccination. Initiation of a new SCIT, SLIT, or OIT should be delayed until 1 week after the day of the second vaccination. For SCIT, we generally recommend an interval of ~ 1 week to COVID-19 vaccination.

Patients with suspected allergic reactions to COVID-19 vaccines can be safely revaccinated after diagnostic work-up

BACKGROUND

When initiating the Danish vaccination program against COVID-19, the incidence of anaphylaxis was estimated to be 10 times higher compared to other virus-based vaccines. In this study, we present data on patients referred with suspected allergic reactions to COVID-19 vaccines. The main purpose of the study is to investigate the incidence and severity of the allergic reactions, and to evaluate the safety of revaccination.

METHODS

All patients in the region of Southern Denmark with case histories of allergic reactions to COVID-19 vaccines in a defined period are included in this study. Diagnostic work up consisted of a detailed case history, evaluation of Brighton level of diagnostic certainty and World Allergy Organization grade of anaphylaxis and skin prick testing- and basophil histamine release testing with COVID-19 vaccines and relevant drug excipients. Patients were revaccinated at the Allergy Center when possible.

RESULTS

Sixty-one patients are included in this study. In 199,377 doses administered, nine patients fulfilled the criteria of anaphylaxis when using the Brighton Criteria (incidence being 45 per million). Of 55 patients with reactions to the first dose, 52 patients were revaccinated without adverse reactions. We found no proven cases of immediate anaphylaxis due to COVID-19 vaccines. By skin prick test, we diagnosed three patients with drug excipient allergy and further a patient with mastocytosis was found.

CONCLUSIONS

Anaphylactic reactions to COVID-19 vaccines are rare and the incidence is similar to what is seen with other virus-based vaccines. Revaccination is safe in the majority of patients; however, allergological evaluation is important since some prove to have drug excipient allergy.

Immunization Catch-Up for Newly Arrived Migrants in France: A Cross-Sectional Study among French General Practitioners

Background: Migrants often undergo an incomplete vaccination program in regards to the French recommendations. The aim of this study was to evaluate the practices of French General Practitioners’ (GPs) in terms of catch-up vaccination. Methods: A cross-sectional study was carried-out in 2017–2018 in France. An online questionnaire was disseminated by email through scholarly societies to GPs involved in the care and the vaccination of migrants. Analyses included univariate and multivariate analysis with a logistic regression model. Results: A total of 216 GPs completed the survey. A majority identified themselves with an average level regarding the prevention of infectious diseases among migrant populations (56.7%) and confirmed this is part of their daily practice (83.3%). The majority of respondents do not perform more than two injections on the same day. When compared to GPs working in health centres, those with a private practice are more likely to report returning to a full primary vaccination schedule (adjusted OR = 2.90, 95% CI [1.29–6.53]). Aside from the serology for hepatitis B and to a lesser extent for measles, other pre-vaccination serologies were not frequently used by GPs. When a migrant declares to be up-to-date with his immunisations, only 56.5% of doctors consider this information reliable. Conclusions: This study clarified the vaccination practices of GPs receiving migrant patients in consultation and showed its heterogeneity. An important need for benchmarks has been identified and these results were used for the elaboration of the French guidelines on vaccines catch-up.

ARIA-EAACI statement on severe allergic reactions to COVID-19 vaccines - An EAACI-ARIA Position Paper

Further to the approval of the Coronavirus disease 2019 (COVID-19) vaccine BNT162b2, several severe anaphylaxis cases occured within the first few days of public vaccination. An investigation is taking place to understand the cases and their triggers. The vaccine will be administered to a large number of individuals worldwide and there are raising concerns that severe adverse events might occur. With the current information, the European Academy of Allergy and Clinical Immunology (EAACI) states its position for the following preliminary recommendations that are to be revised as soon as more data emerge. To minimize the risk of severe allergic reactions in vaccinated individuals, it is urgently required to understand the specific nature of the reported severe allergic reactions, including the background medical history of the individuals affected and the mechanisms involved. To achieve this goal, all clinical and laboratory information should be collected and reported. Mild and moderate allergic patients should not be excluded from the vaccine as this could have a significant impact on reaching the goal of population immunity. Healthcare practitioners vaccinating against COVID-19 are required to be sufficiently prepared to recognize and treat anaphylaxis properly with the ability to administer adrenaline. Further to vaccine administration, a mandatory observation period of at least 15 minutes should be followed for all individuals. The current data have not shown any higher risk for patients suffering from allergic rhinitis or asthma, and this message should be clearly stated by physicians to enable our patients to trust the vaccine. More than 30% of the population suffers from allergic diseases and the benefit of the vaccination clearly outweighs the risk of severe COVID-19 development.

Schwere allergische Reaktionen nach COVID-19-Impfung mit dem Impfstoff von Pfizer/BioNTech in Großbritannien und USA

Zwei Mitarbeiter des National Health Service (NHS) in England entwickelten nach der Verabreichung des BNT162b2-Impfstoffs von BionNTech gegen COVID-19 schwere allergische Reaktionen. Die britische Fachinformation für den BNT162b2-Impfstoff enthält bereits Hinweise auf eine Kontraindikation zur Anwendung bei Personen, die allergisch auf den Impfstoff oder einen seiner Bestandteile reagiert haben. Als Vorsichtsmaßnahme hat die englische Regulationsbehörde für Arzneimittel und Gesundheitsprodukte (MHRA) eine vorläufige Anleitung herausgegeben, "Patienten mit schweren Allergien" grundsätzlich nicht zu impfen. Allergische Reaktionen auf Impfstoffe sind sehr selten, aber Impfstoffkomponenten verursachen bekanntermaßen allergische Reaktionen. BNT162b2 ist ein Impfstoff, der auf einer in Lipidnanopartikel eingebetteten mRNA basiert und mit weiteren Substanzen angereichert wird, um den Transport in die Zellen zu ermöglichen. In der zentralen klinischen Phase-III-Studie wurde der BNT162b2-Impfstoff im Allgemeinen gut vertragen. Impfstoffe gelten als eine der wirksamsten Maßnahmen im Bereich der öffentlichen Gesundheit. Schwere allergische Reaktionen auf Impfstoffe sind selten, können jedoch lebensbedrohlich sein. Es ist ratsam, die Impfteams auf diese Gefahr aufmerksam zu machen und angemessene Vorsichtsmaßnahmen zu treffen, während mehr Erfahrungen mit dem neuen Impfstoff gesammelt werden.

Allergic Reactions to Current Available COVID-19 Vaccinations: Pathophysiology, Causality, and Therapeutic Considerations

Vaccines constitute the most effective medications in public health as they control and prevent the spread of infectious diseases and reduce mortality. Similar to other medications, allergic reactions can occur during vaccination. While most reactions are neither frequent nor serious, anaphylactic reactions are potentially life-threatening allergic reactions that are encountered rarely, but can cause serious complications. The allergic responses caused by vaccines can stem from activation of mast cells via Fcε receptor-1 type I reaction, mediated by the interaction between immunoglobulin E (IgE) antibodies against a particular vaccine, and occur within minutes or up to four hours. The type IV allergic reactions initiate 48 h after vaccination and demonstrate their peak between 72 and 96 h. Non-IgE-mediated mast cell degranulation via activation of the complement system and via activation of the Mas-related G protein-coupled receptor X2 can also induce allergic reactions. Reactions are more often caused by inert substances, called excipients, which are added to vaccines to improve stability and absorption, increase solubility, influence palatability, or create a distinctive appearance, and not by the active vaccine itself. Polyethylene glycol, also known as macrogol, in the currently available Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines, and polysorbate 80, also known as Tween 80, in AstraZeneca and Johnson & Johnson COVID-19 vaccines, are excipients mostly incriminated for allergic reactions. This review will summarize the current state of knowledge of immediate and delayed allergic reactions in the currently available vaccines against COVID-19, together with the general and specific therapeutic considerations. These considerations include: The incidence of allergic reactions and deaths under investigation with the available vaccines, application of vaccination in patients with mast cell disease, patients who developed an allergy during the first dose, vasovagal symptoms masquerading as allergic reactions, the COVID-19 vaccination in pregnancy, deaths associated with COVID-19 vaccination, and questions arising in managing of this current ordeal. Careful vaccine-safety surveillance over time, in conjunction with the elucidation of mechanisms of adverse events across different COVID-19 vaccine platforms, will contribute to the development of a safe vaccine strategy. Allergists’ expertise in proper diagnosis and treatment of allergic reactions is vital for the screening of high-risk individuals.

Severe allergic reactions after COVID-19 vaccination with the Pfizer/BioNTech vaccine in Great Britain and USA: Position statement of the German Allergy Societies: Medical Association of German Allergologists (AeDA), German Society for Allergology and Clinical Immunology (DGAKI) and Society for Pediatric Allergology and Environmental Medicine (GPA)

Two employees of the National Health Service (NHS) in England developed severe allergic reactions following administration of BNT162b2 vaccine against COVID-19 (coronavirus disease 2019). The British SmPC for the BNT162b2 vaccine already includes reference to a contraindication for use in individuals who have had an allergic reaction to the vaccine or any of its components. As a precautionary measure, the Medicines and Healthcare products Regulatory Agency (MHRA) has issued interim guidance to the NHS not to vaccinate in principle in "patients with severe allergies". Allergic reactions to vaccines are very rare, but vaccine components are known to cause allergic reactions. BNT162b2 is a vaccine based on an mRNA embedded in lipid nanoparticles and blended with other substances to enable its transport into the cells. In the pivotal phase III clinical trial, the BNT162b2 vaccine was generally well tolerated, but this large clinical trial, used to support vaccine approval by the MHRA and US Food and Drug Administration, excluded individuals with a "history of a severe adverse reaction related to the vaccine and/or a severe allergic reaction (e.g., anaphylaxis) to a component of the study medication". Vaccines are recognized as one of the most effective public health interventions. This repeated administration of a foreign protein (antigen) necessitates a careful allergological history before each application and diagnostic clarification and a risk-benefit assessment before each injection. Severe allergic reactions to vaccines are rare but can be life-threatening, and it is prudent to raise awareness of this hazard among vaccination teams and to take adequate precautions while more experience is gained with this new vaccine.

Allergische Reaktionen auf COVID-19-Impfungen – Was HNO-Ärzte wissen sollten – Teil 1: Allgemeine Aspekte von Allergien auf Impfstoffe, immunologische Grundlagen von Allergien auf Impfstoffe, Immunmechanismen von allergischen und pseudoallergischen Reaktionen, Teil 2: Charakteristiken der mRNA-Impfstoffe BNT162b2 und mRNA-1273 zur Prophylaxe von COVID-19 und assoziierte Immunphänomene, Teil 3: Praktische Aspekte der Prophylaxe, Diagnostik und Therapie von Allergien auf COVID-19-Impfstoffe

With BNT162b2 (approved in the EC on 27^th of December 2020) and mRNA-1273 (approved in the EC on 6^th of January 2021) for the first time ever two RNA-vaccines received conditional approval within the EC in order to effectively combat the SARS-COV2 pandemic. The emergence of sporadic cases of anaphylaxis following vaccination with these new compounds and the identification of PEGs (polyethylenglycols) as potential, widely used but yet usually unknown culprits have led to uncertainty among treating physicians and patients. The aim of this article series is to summarize current available pathophysiological and clinical information (part 1), to describe the characteristics of the vaccines (part 2) and to provide practical solutions for diagnosis and treatment of potential allergy against mRNACovid19 vaccines.

COVID-19 Vaccine-associated Anaphylaxis and Allergic Reactions: Consensus Statements of the KAAACI Urticaria/Angioedema/Anaphylaxis Working Group

In the era of novel coronavirus epidemics, vaccines against coronavirus disease 2019 (COVID-19) have been recognized as the most effective public health interventions to control the pandemic. An adverse event following immunization (AEFI) is defined as any untoward occurrence following immunization, and the majority of AEFIs are caused by protective immune responses stimulated by vaccines. Most of the reported AEFIs are not serious, and many are not immunologically mediated or even reproducible on re-exposure. However, uncommon severe allergic adverse reactions, such as anaphylaxis or other allergic reactions, can occur after vaccinations. Confirmed allergic reactions to vaccines may be caused by residual non-human protein, preservatives, or stabilizers in the vaccine formulation (also known as excipients). There are 2 main potential allergenic/immunogenic excipients in COVID-19 vaccines, polyethylene glycol (PEG) and polysorbate 80. PEG, also known as macrogol, is an ingredient in various laxatives and injectable formulations, such as depot steroids. Polysorbate 80 is present in various medical products, creams, ointments, lotions, and medication tablets. Contraindications to the administration of COVID-19 vaccines include a previous history of severe allergic reactions to the first dose of COVID-19 vaccine or proven hypersensitivity to a vaccine component, such as PEG or polysorbate 80. Anaphylaxis or other allergic reactions following immunization can cause fear and loss of confidence in the safety of vaccines among the public. A better understanding of these events is thought to help alleviate concerns about the current COVID-19 vaccines and provide reassurance to the general population by analyzing the exact incidence of anaphylaxis and potential risk factors. COVID-19 vaccine-associated anaphylaxis could be prevented and managed by risk stratification based on our local and global experience.

Epitope-Based Immunoinformatics Approach on Nucleocapsid Protein of Severe Acute Respiratory Syndrome-Coronavirus-2

With an increasing fatality rate, severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has emerged as a promising threat to human health worldwide. Recently, the World Health Organization (WHO) has announced the infectious disease caused by SARS-CoV-2, which is known as coronavirus disease-2019 (COVID-2019), as a global pandemic. Additionally, the positive cases are still following an upward trend worldwide and as a corollary, there is a need for a potential vaccine to impede the progression of the disease. Lately, it has been documented that the nucleocapsid (N) protein of SARS-CoV-2 is responsible for viral replication and interferes with host immune responses. We comparatively analyzed the sequences of N protein of SARS-CoV-2 for the identification of core attributes and analyzed the ancestry through phylogenetic analysis. Subsequently, we predicted the most immunogenic epitope for the T-cell and B-cell. Importantly, our investigation mainly focused on major histocompatibility complex (MHC) class I potential peptides and NTASWFTAL interacted with most human leukocyte antigen (HLA) that are encoded by MHC class I molecules. Further, molecular docking analysis unveiled that NTASWFTAL possessed a greater affinity towards HLA and also available in a greater range of the population. Our study provides a consolidated base for vaccine design and we hope that this computational analysis will pave the way for designing novel vaccine candidates.

Immunization practices in children with a history of allergies

Aim:

In the presence of food allergies, especially egg allergies, primary physicians in Turkey avoid vaccine administration and refer children to a hospital setting. We aimed to evaluate children who had allergies or suspected allergies and were referred to our Well Child Clinic in a university hospital for vaccination.

Material and Methods:

Charts of all children referred to our clinic due to concerns for allergies in the last two years, were reviewed. Demographic data, laboratory evaluation and reactions after immunization were recorded.

Results:

A total of 122 children with or without a confirmed diagnosis of allergies were referred by primary physicians. In the history, 50 children (43.5%) had reactions with egg, 42 (36.5%) had reactions with multiple foods, nine (7.8%) had reactions with milk and seven (6.1%) had reactions with a previous vaccination. The most common reaction was rash (n=89, 86.4%). Nine children reported anaphylaxis. Skin testing or serum allergen specific IgE measurement revealed that 66 (54.1%) children had sensitization to egg white and 25 (20.5%) had sensitization to egg yolk. Most children (n=87, 71.9%) were referred for all the 12^th-month vaccines, and 21 children were referred only for the measles-mumps-rubella vaccine (n=21, 17.4%). The median delay time in the administration of the measles-mumps-rubella vaccine was 20.0 (interquartile range: 8.7-41.2) days. No reaction was observed except for one child reporting a slight rash several hours after vaccination.

Conclusion:

Egg allergy was the most common barrier of vaccine administration in children referred from family physicians. Given the absence of any reactions, we support the administration of the measles-mumps-rubella vaccine in primary care settings to prevent delays in national vaccine schedule.

Diagnosis and management of hypersensitivity reactions to vaccines

INTRODUCTION

Many countries in Europe now recommend and enforce mandatory vaccinations to improve vaccination coverage. Thus, the number of adverse events following immunization (AEFI) may show an increase. Among these events, severe hypersensitivity reactions to vaccines are rare. However, it is important that they be identified and recognized so that they may be adequately managed.

AREAS COVERED

The literature search was undertaken through PubMed and Embase to identify English-language papers focusing on hypersensitivity to vaccines.

EXPERT OPINION

Hypersensitivity reactions following vaccinations are rare and are classified according to their chronology and extension: immediate when they occur within the first 4 hours following administration and non-immediate when they occur later. Local reactions are the most common adverse event following injection of vaccines and generally do not require any allergy workup. Immediate reactions, however, are potentially IgE-mediated and require an allergy workup. In general, a previously known food allergy (i.e., egg or milk) is not a contraindication to immunizations. Patients with a known allergy to gelatin, yeast, latex, antibiotics, or other specific components of vaccines require an allergy workup before administration of the vaccine.

Drug Allergy in Children: What Should We Know?

The drug allergy "label" may have a lifetime of consequences for a child. Many children with alleged drug allergies are proven to be tolerant to the culprit medication when challenged. The field of drug hypersensitivity is a recently evolving field of research, but studies on its epidemiology and diagnostic tools are lacking in children. Clinical history is significant in the diagnosis and classification of drug hypersensitivity in children. Diagnostic tools have been evaluated in a limited number of children; therefore, the guidelines are mainly in line with those for adults. Here, we review the clinical characteristics, main drugs, risk factors, and diagnosis of drug hypersensitivity to aid in its accurate diagnosis in children.

Immune-mediated adverse reactions to vaccines

Vaccination continues to be the single most important and successful public health intervention, due to its prevention of morbidity and mortality from prevalent infectious diseases. Severe immunologically mediated reactions are rare and less common with the vaccine than the true infection. However, these events can cause public fearfulness and loss of confidence in the safety of vaccination. In this paper, we perform a systematic literature search and narrative review of immune-mediated vaccine adverse events and their known and proposed mechanisms, and outline directions for future research. Improving our knowledge base of severe immunologically mediated vaccine reactions and their management drives better vaccine safety and efficacy outcomes.

Does Food Allergy Require Any Change in Measles-Mumps-Rubella Vaccination?

OBJECTIVES

To determine the allergic reactions that develop after Measles and Measles-Mumps-Rubella (MMR) vaccination, and whether any delay in the timing of vaccination occurs in children with food allergy.

METHODS

Children with food allergy who were admitted to the Şişli Hamidiye Etfal Training and Research Hospital Healthy Child Clinic between 1st January 2015 and 30th June 2018 for Measles or MMR vaccination were studied retrospectively. Their age, delayed days of vaccination, the types of allergic food, the results of the specific IgE and skin tests, and any reaction after the vaccination were recorded.

RESULTS

During the study period, 159 patients were vaccinated and 170 doses of Measles or MMR vaccine were administered. Children allergic to egg were 50.3%, allergic to egg and milk were 25.8%, and 13.2% had multiple food allergy including egg. The rate of post-vaccination reactions in the patients with food allergy was 1.76%. Minor reaction was observed in three patients and no anaphylaxis was seen in any patient. Delayed days of vaccination in the patients referred by another center were greater than followed-up by present clinic (p < 0.001).

CONCLUSIONS

Any serious allergic reaction was not observed in this study. Food allergy does not necessitate modification of routine vaccination. Anaphylaxis may develop in any vaccinated child regardless of whether he/she has food allergy or not. Therefore, vaccines should be administered in a healthcare facility that can treat anaphylaxis.

Vaccine-associated hypersensitivity

Vaccine-associated hypersensitivity reactions are not infrequent; however, serious acute-onset, presumably IgE-mediated or IgG and complement-mediated anaphylactic or serious delayed-onset T cell-mediated systemic reactions are considered extremely rare. Hypersensitivity can occur because of either the active vaccine component (antigen) or one of the other components. Postvaccination acute-onset hypersensitivity reactions include self-limited localized adverse events and, rarely, systemic reactions ranging from urticaria/angioedema to full-blown anaphylaxis with multisystem involvement. Risk of anaphylaxis after all vaccines is estimated to be 1.31 (95% CI, 0.90-1.84) per million vaccine doses, respectively. Serious hypersensitivity reactions after influenza vaccines are particularly important because of the large number of persons vaccinated annually. Influenza vaccines are unique in requiring annual changes in the vaccines' antigenic composition to match the predicted circulating influenza strains. Recently, novel influenza vaccine types were introduced in the United States (recombinant vaccines, some with higher antigen content and a new adjuvanted vaccine). Providers should be aware of changing recommendations on the basis of recent published evidence for persons with a history of egg allergy to receive annual influenza vaccination. Further research is needed to elucidate the pathophysiology and risk factors for reported vaccine-associated adverse events. Further research is also needed to determine whether repeated annual inactivated influenza vaccination, the number of vaccine antigens administered at the same time, and the current timing of routine infant vaccinations are optimal for overall population well-being.

International Consensus (ICON): allergic reactions to vaccines

BACKGROUND

Routine immunization, one of the most effective public health interventions, has effectively reduced death and morbidity due to a variety of infectious diseases. However, allergic reactions to vaccines occur very rarely and can be life threatening. Given the large numbers of vaccines administered worldwide, there is a need for an international consensus regarding the evaluation and management of allergic reactions to vaccines.

METHODS

Following a review of the literature, and with the active participation of representatives from the World Allergy Organization (WAO), the European Academy of Allergy and Clinical Immunology (EAACI), the American Academy of Allergy, Asthma, and Immunology (AAAAI), and the American College of Allergy, Asthma, and Immunology (ACAAI), the final committee was formed with the purpose of having members who represented a wide-range of countries, had previously worked on vaccine safety, and included both allergist/immunologists as well as vaccinologists.

RESULTS

Consensus was reached on a variety of topics, including: definition of immediate allergic reactions, including anaphylaxis, approaches to distinguish association from causality, approaches to patients with a history of an allergic reaction to a previous vaccine, and approaches to patients with a history of an allergic reaction to components of vaccines.

CONCLUSIONS

This document provides comprehensive and internationally accepted guidelines and access to on-line documents to help practitioners around the world identify allergic reactions following immunization. It also provides a framework for the evaluation and further management of patients who present either following an allergic reaction to a vaccine or with a history of allergy to a component of vaccines.

The baculovirus expression vector system: A commercial manufacturing platform for viral vaccines and gene therapy vectors

The baculovirus expression vector system (BEVS) platform has become an established manufacturing platform for the production of viral vaccines and gene therapy vectors. Nine BEVS-derived products have been approved - four for human use (Cervarix(®), Provenge(®), Glybera(®) and Flublok(®)) and five for veterinary use (Porcilis(®) Pesti, BAYOVAC CSF E2(®), Circumvent(®) PCV, Ingelvac CircoFLEX(®) and Porcilis(®) PCV). The BEVS platform offers many advantages, including manufacturing speed, flexible product design, inherent safety and scalability. This combination of features and product approvals has previously attracted interest from academic researchers, and more recently from industry leaders, to utilize BEVS to develop next generation vaccines, vectors for gene therapy, and other biopharmaceutical complex proteins. In this review, we explore the BEVS platform, detailing how it works, platform features and limitations and important considerations for manufacturing and regulatory approval. To underscore the growth in opportunities for BEVS-derived products, we discuss the latest product developments in the gene therapy and influenza vaccine fields that follow in the wake of the recent product approvals of Glybera(®) and Flublok(®), respectively. We anticipate that the utility of the platform will expand even further as new BEVS-derived products attain licensure. Finally, we touch on some of the areas where new BEVS-derived products are likely to emerge.