Non-immunoglobulin E-mediated allergy associated with Pfizer-BioNTech coronavirus disease 2019 vaccine excipient polyethylene glycol

Development of anti-PEG IgG/IgM/IgE ELISA assays for profiling anti-PEG immunoglobulin response in PEG-sensitized individuals and patients with alpha-gal allergy

Polyethylene glycol (PEG) is frequently used in various protein and nanomedicine therapeutics. However, various studies have shown that select PEGylated therapeutics can induce production of anti-PEG antibodies (APA), potentially culminating in rapid clearance from the systemic circulation, loss of efficacy and possibly increased risks of allergic reactions. Although IgE is a frequent cause of immediate hypersensitivity reactions (IHR), the role of IgE APA in PEG-related IHR is not well understood, due in part to a lack of standardized assays for measuring IgE APA. Here, we developed a rigorous competitive ELISA method to measure the concentrations of various APA isotypes, including IgE, with picomolar sensitivities. In a small number of serum samples from patients with known PEG allergy, the assay allowed us to detect a strong correlation between IgG and IgE APA in individuals with history of allergic reactions to PEG or PEGylated drugs, but not between IgM and IgE APA. We detected appreciable levels of IgG and IgM APA in individuals with history of alpha-gal allergy, however, they were not elevated relative to those detected in other healthy controls, and we found no pre-existing IgE APA. While preliminary and should be further investigated, these results suggest that differences in the route and mechanism of PEG exposure may drive variability in APA response.

Anaphylatoxin Complement 5a in Pfizer BNT162b2-Induced Immediate-Type Vaccine Hypersensitivity Reactions

The underlying immunological mechanisms of immediate-type hypersensitivity reactions (HSR) to COVID-19 vaccines are poorly understood. We investigate the mechanisms of immediate-type hypersensitivity reactions to the Pfizer BNT162b2 vaccine and the response of antibodies to the polyethylene glycol (PEG)ylated lipid nanoparticle after two doses of vaccination. Sixty-seven participants, median age 35 and 77.3% females who tolerated two doses of the BNT162b2 vaccine (non-reactors), were subjected to various blood-sampling time points. A separate group of vaccine reactors (10 anaphylaxis and 37 anonymised tryptase samples) were recruited for blood sampling. Immunoglobulin (Ig)G, IgM and IgE antibodies to the BNT162b2 vaccine, biomarkers associated with allergic reaction, including tryptase for anaphylaxis, complement 5a(C5a), intercellular adhesion molecule 1 (ICAM-1) for endothelial activation and Interleukin (IL)-4, IL-10, IL-33, tumour necrosis factor (TNF) and monocyte chemoattractant protein (MCP-1), were measured. Basophil activation test (BAT) was performed in BNT162b2-induced anaphylaxis patients by flow cytometry. The majority of patients with immediate-type BNT162b2 vaccine HSR demonstrated raised C5a and Th2-related cytokines but normal tryptase levels during the acute reaction, together with significantly higher levels of IgM antibodies to the BNT162b2 vaccine (IgM 67.2 (median) vs. 23.9 AU/mL, p < 0.001) and ICAM-1 when compared to non-reactor controls. No detectable IgE antibodies to the BNT162b2 vaccine were found in these patients. The basophil activation tests by flow cytometry to the Pfizer vaccine, 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol (DMG-PEG) and PEG-2000 were negative in four anaphylaxis patients. Acute hypersensitivity reactions post BNT162b2 vaccination suggest pseudo-allergic reactions via the activation of anaphylatoxins C5a and are independent of IgE-mechanisms. Vaccine reactors have significantly higher levels of anti-BNT162b2 IgM although its precise role remains unclear.

Serum polyethylene glycol-specific IgE and IgG in patients with hypersensitivity to COVID-19 mRNA vaccines

BACKGROUND

The mechanism of allergic reactions to COVID-19 mRNA vaccines has not been clarified. Polyethylene glycol (PEG) is a potential antigen in the components of vaccines. However, there is little evidence that allergy after COVID-19 mRNA vaccination is related to PEG. Furthermore, the role of polysorbate (PS) as an antigen has also not been clarified. The objective of this study was to investigate whether PEG and PS allergies are reasonable causes of allergic symptoms after vaccination by detecting PEG-specific and PS-specific antibodies.

METHODS

Fourteen patients who developed immediate allergic reactions to BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccines and nineteen healthy controls who did not present allergic symptoms were recruited. Serum PEG-specific immunoglobulin E (IgE) and immunoglobulin G (IgG) and PS-specific IgE and IgG were measured by enzyme-linked immunosorbent assay. Skin tests using PEG-2000 and PS-80 were applied to five patients and three controls.

RESULTS

Serum levels of PEG-specific IgE and IgG in patients with immediate allergic reactions to the COVID-19 mRNA vaccine were higher than those in the control group. Serum levels of PS-specific IgE in patients with allergy to the vaccine were higher than those in patients of the control group. Intradermal tests using PEG verified the results for PEG-specific IgE and IgG.

CONCLUSIONS

The results suggest that PEG is one of the antigens in the allergy to COVID-19 mRNA vaccines. Cross-reactivity between PEG and PS might be crucial for allergy to the vaccines. PEG-specific IgE and IgG may be useful in diagnosing allergy to COVID-19 mRNA vaccines.

Immediate hypersensitivity to COVID-19 vaccines: Focus on biological diagnosis

Soon after the release of the new anti-COVID mRNA vaccines, reports came in from the US and the UK of anaphylactic reactions. Fueled by the necessary caution toward these new vaccine platforms, these reports had a great impact and were largely commented upon in the scientific literature and global media. The current estimated frequency is of 5 cases per million doses. Very little biological data are presented in the literature to support the anaphylaxis diagnosis in these patients in addition to skin tests. Allergic reactions to vaccines are rare and mostly due to vaccine excipient. Therefore, the poly-ethylene-glycol (PEG) present in both mRNA formulation, and already known to be immunogenic, was soon suspected to be the potential culprit. Several hypersensitivity mechanisms to PEG or to other vaccine components can be suspected, even if the classical IgE-dependent anaphylaxis seems to be one of the most plausible candidates. In the early 2022, the international guidelines recommended to perform skin prick tests and basophil activation tests (BAT) in people experiencing allergic reaction to the first dose of COVID-19 vaccine or with a history of PEG allergy. The aim of this review is to discuss the main potential mechanisms of immediate allergy to COVID19 vaccines based on published data, together with the various techniques used to confirm or not sensitization to one component.

COVID vaccination can be completed in subjects with a history of allergic reactions to the vaccines or their components - experience from a specialist clinic in South Australia

The development of vaccines against SARS-CoV2 has been a key public health response to the COVID-19 pandemic. However, since their introduction there have been reports of anaphylactic reactions in vaccinees with history of allergy. We developed an allergy testing protocol allowing vaccination with available COVID-19 vaccines in Australia. Patients referred to a state-wide COVID-19 vaccine allergy clinic between March and August 2021 with a history of allergy underwent skin prick testing and intradermal testing to both available vaccine formulations (BNT162b2, ChAdOx1-S), excipients (polyethylene glycol, polysorbate 80), excipient-containing medications, and controls. Where available, basophil activation testing was conducted. 53 patients underwent testing for possible excipient allergy (n = 19), previous non-COVID vaccine reaction (n = 13), or previous reaction to dose 1 of COVID-19 vaccine (n = 21). Patients were predominantly female (n = 43, 81%), aged 18-83 (median 54) years. 44 patients tested negative and 42 of these received at least their first dose of a COVID-19 vaccine. 9 patients tested positive to excipients or excipient-containing medication only (n = 3), or vaccines (n = 6). 5 patients were positive to just BNT162b2, 3/5 have been vaccinated with ChAdOx1-S. 1 who was skin test positive to both vaccines, but negative BAT to ChAdOx1-S was successfully vaccinated with ChAdOx1-S. Even in a high-risk population, most patients can be vaccinated with available COVID-19 vaccines. This paper reports local experiences using a combined allergy testing protocol with skin testing and BAT during the pandemic. This article is protected by copyright. All rights reserved.

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.

Do basophil activation tests help elucidate allergic reactions to the ingredients in COVID-19 vaccines?

The worldwide use of COVID-19 vaccines has shown that immediate allergic reactions to the ingredients are rare but should be clarified by means of an allergological work-up. This review aims to highlight the current state of knowledge and possible pathogenesis based on the literature published to date. In addition to recording a detailed history and performing skin tests, cellular tests (basophil activation or basophil histamine release test) by using the vaccines or modified compounds containing polyethylene glycol (PEG), rather than unmodified PEGs, have proven to be particularly helpful. Negative results with vaccines seem to indicate tolerance. Details of the performance of these cellular tests with different vaccines, PEGs of different molecular weights, other ingredients of the vaccines, as well as other PEGylated drugs, and the results in the context of COVID-19 vaccination of various working groups worldwide are summarized.

Biomarqueurs et tests fonctionnels dans l’hypersensibilité immédiate aux vaccins ARNm dirigés contre le SARS-CoV-2

Les phénomènes d’hypersensibilité aux vaccins à ARNm dirigés contre le SARS-CoV-2 sont très rares. Ils peuvent être liés à un mécanisme IgE-dépendant impliquant les PEG contenus dans les vaccins sous forme de liposomes. Une activation directe de la voie classique du complément (CARPA) a été également fortement suspectée. En complément des tests cutanés, des biomarqueurs ont été proposés, en particulier la recherche d’anticorps anti-PEG, le dosage des anaphylatoxines C5a et C3a ou du complexe soluble C5b-9. Les anticorps anti-PEG sont dosables par quelques méthodes non standardisées mais leur présence dans ces réactions n’a pas été confirmée. Il en est de même pour les protéines du complément. L’histamine et la tryptase ont rarement pu être dosées au moment de la réaction et leur augmentation est inconstante selon les études. Une tryptase basale un peu élevée chez certains patients suggère qu’une hyper-alpha-tryptasémie pourrait être impliquée. Le test d’activation des basophiles s’est imposé comme un examen pouvant être utile mais les résultats sont encore difficiles à interpréter en raison de la variabilité des allergènes utilisés : PEG, PEG sous forme de liposomes ou vaccin lui-même. L’absence de positivité des tests cutanés alors que les basophiles sont capables de s’activer en présence du même allergène ex vivo chez certains patients est en faveur, dans ce cas, d’un phénomène non IgE-dépendant. En conclusion, dans l’exploration des réactions immédiates aux vaccins à ARNm contre le SARS-CoV-2, l’importance de la place de marqueurs biologiques nécessite des études complémentaires afin de mieux identifier les acteurs et les mécanismes impliqués.