Contact allergy to aluminium induced by commonly used pediatric vaccines

Cutaneous adverse reactions associated with COVID-19 vaccines: Current evidence and potential immune mechanisms

As the number of vaccinated individuals has increased, there have been increasing reports of cutaneous hypersensitivity reactions. The main COVID-19 vaccines administered include messenger ribonucleic acid vaccines, non-replicating viral vector vaccines, inactivated whole-virus vaccines, and protein-based vaccines. These vaccines contain active components such as polyethylene glycol, polysorbate 80, aluminum, tromethamine, and disodium edetate dihydrate. Recent advances in understanding the coordination of inflammatory responses by specific subsets of lymphocytes have led to a new classification based on immune response patterns. We categorize these responses into four patterns: T helper (Th)1-, Th2-, Th17/22-, and Treg-polarized cutaneous inflammation after stimulation of COVID-19 vaccines. Although the association between COVID-19 vaccination and these cutaneous adverse reactions remains controversial, the occurrence of rare dermatoses and their short intervals suggest a possible relationship. Despite the potential adverse reactions, the administration of COVID-19 vaccines is crucial in the ongoing battle against severe acute respiratory syndrome coronavirus 2.

Risk factors for granulomas in children following immunisation with aluminium adsorbed vaccines: A Danish population-based cohort study

BACKGROUND

Aluminium adsorbed vaccines may in some children cause severely itching nodules at the injection site, known as vaccination granulomas.

OBJECTIVE

To investigate vaccine-, child- and maternal level risk factors for the development of vaccination granulomas following immunisation with aluminium adsorbed vaccines.

METHODS

A Danish population-based cohort study with 553 932 children born in Denmark from 1 January 2009 to 31 December 2018, vaccinated with an aluminium adsorbed vaccine during the first year of life, followed until 31 December 2020. Poisson regression was used to estimate granuloma rate ratios according to type of adjuvant, accumulated dose of aluminium, timing of vaccination appointments, sex, gestational age, having siblings with granulomas, maternal age, and maternal ethnicity.

RESULTS

We identified 1 901 vaccination granuloma cases (absolute risk, 0.34%). Among vaccine level factors, revaccination (third vs first vaccination appointment, adjusted rate ratio [RR] 1.26, 95% confidence interval [CI] 1.03-1.55), the specific adjuvant used (aluminium phosphate vs hydroxide, RR 0.58, 95% CI 0.48-0.70) and dosage (≥1.0 mg vs <1.0 mg, RR 1.34, 95% CI 1.19-1.52) were associated with risk of granulomas; the timing of vaccination appointments was not. Among child level factors, female sex (vs males, RR 1.12, 95% CI, 1.02-1.22), prematurity (vs term birth, RR 0.71, 95% CI, 0.54-0.93) and having sibling(s) with granulomas (vs no siblings with granulomas, RR 46.15, 95% CI, 33.67-63.26) were associated with risk of granulomas. Among maternal level factors, non-Danish ethnicity (vs. Danish, RR 0.51, 95% CI, 0.42-0.63) and young maternal age (<20 yrs. vs 20-39 yrs., RR 0.46, 95% CI 0.25-0.83) were associated with risk of granulomas.

CONCLUSIONS

Several risk factors for vaccination granulomas at both the vaccine, child, and maternal level, was identified. Reducing the dose of aluminium or replacing aluminium hydroxide with aluminium phosphate could reduce the risk of granulomas. However, this must be balanced against the potential for reduced immunogenicity.

Delayed allergic skin reactions to vaccines

Background: Recent advances in vaccination against the severe acute respiratory syndrome coronavirus 2 pandemic have brought allergists and dermatologists to the forefront because both immediate and delayed hypersensitivity reactions have been reported. Objective: This literature review focused on delayed reactions to vaccines, including possible causative agents and practical information on how to diagnose, evaluate with patch testing, and manage subsequent dose administration. Methods: Currently published reviews and case reports in PubMed, along with data on vaccines from the Centers for Disease Control and Prevention web site. Relevant case reports and reviews that focused on delayed reactions to vaccines were selected. Results: Most delayed hypersensitivity reactions to vaccines include cutaneous manifestations, which vary from local persistent pruritic nodules to systemic rashes. The onset is usually within a few days but can be delayed by weeks. Multiple excipients have been identified that have been implicated in delayed vaccine reactions, including thimerosal, formaldehyde, aluminum, antibiotics, and gelatin. Treatment with antihistamines, topical corticosteroids, or systemic corticosteroids alleviates symptoms in most patients. Such reactions are generally not contraindications to future vaccination. However, for more-severe reactions, patch testing for causative agents can be used to aid in diagnosis and approach further vaccination. Conclusion: Delayed-type hypersensitivity reactions to vaccines are not uncommon. If needed, patch testing can be used to confirm agents, including antibiotics, formaldehyde, thimerosal, and aluminum. In most cases, delayed cutaneous reactions are not contraindications to further vaccine administration.

Aluminium contact allergy without vaccination granulomas: A systematic review and meta-analysis

Aluminium contact allergy is mainly seen as granulomas following immunization with aluminium-adsorbed vaccines and contact allergy following epicutaneous exposure may be overlooked. To investigate the prevalence of aluminium allergy confirmed by patch testing, with no association with vaccination granulomas, and explore whether epicutaneous exposure to aluminium can contribute to allergic contact dermatitis. Two authors independently searched PubMed and MEDLINE (OVID) for case studies on contact allergy to aluminium proven by patch testing. Age-stratified meta-analyses to calculate the pooled prevalence were performed. Twenty-five studies describing a total of 73 cases were included in the review. Seven studies were suitable for meta-analyses. The prevalence of aluminium contact allergy was 5.61% (95% confidence interval [CI] 0.12%-11.08%) for children and 0.36% (95% CI 0.04%-0.67%) for adults. The studies described a variety of epicutaneous exposures, where metallic aluminium, topical medicaments, and deodorants were the main sources. Aluminium sensitization without a known exposure source was described in 10 of the 25 articles. The prevalence of aluminium contact allergy in the general public may be higher than expected and not solely related to vaccination granulomas. However, the clinical relevance is rare if not related to granulomas.

The science of vaccine safety: Summary of meeting at Wellcome Trust

Vaccines are everywhere hugely successful but are also under attack. The reason for the latter is the perception by some people that vaccines are unsafe. However that may be, vaccine safety, life any other scientific subject, must be constantly studied. It was from this point of view that a meeting was organized at the Wellcome Trust in London in May 2019 to assess some aspects of vaccine safety as subjects for scientific study. The objective of the meeting was to assess what is known beyond reasonable doubt and conversely what areas need additional studies. Although the meeting could not cover all aspects of vaccine safety science, many of the most important issues were addressed by a group of about 30 experts to determine what is already known and what additional studies are merited to assess the safety of the vaccines currently in use. The meeting began with reviews of the current situation in different parts of the world, followed by reviews of specific controversial areas, including the incidence of certain conditions after vaccination and the safety of certain vaccine components. Lastly, information about the human papillomavirus vaccine was considered because its safety has been particularly challenged by vaccine opponents. The following is a summary of the meeting findings. In addition to this summary, the meeting organizers will explore opportunities to perform studies that would enlarge knowledge of vaccine safety.

Safety and biocompatibility of injectable vaccine adjuvants composed of thermogelling block copolymer gels

Injectable thermogelling polymers have been recently investigated as novel adjuvants and delivery systems for next generation vaccines. As research into natural and synthetic biocompatible polymers progresses, the safety and biocompatibility of these compounds is of paramount importance. We have developed cationic pentablock copolymer (PBC) vaccine adjuvants based on Pluronic F127, a thermogelling triblock copolymer that has been approved by the FDA for multiple applications, and methacrylated poly(diethyl amino)ethyl methacrylate outer blocks. These novel materials have been demonstrated to effectively create an antigen depot, minimally impact antigen stability, and enhance the immune response to antigens (i.e., adjuvanticity) in mice. In this work, we investigated the safety and biocompatibility of the parent triblock Pluronic gels and the cationic PBC gels in mice. Histological analysis showed no injection site reactions and no damage to the liver or kidneys was observed upon administering the block copolymer formulations. However, the subcutaneous injection of a thermogelling Pluronic solution induced increased levels of lipids in the blood, with no further deleterious effects observed from the addition of the cationic outer blocks. This hyperlipidemia resolved within 30 days after the administration of the Pluronic formulation. To mitigate this adverse effect, the vaccine adjuvant formulations were modified by adding poly(vinyl alcohol), which allowed gelation, while reducing the amount of Pluronic in the formulation. This modified formulation abrogated the observed hyperlipidemia and no adverse effects were observed in the serum through biomarker analysis or at the injection site (i.e., inflammation) in comparison to the responses induced by administration of saline or incomplete Freund's adjuvant. These studies provide a foundation to developing these gels as adjuvants for next generation vaccines. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1754-1762, 2019.

Unraveling the enigma: elucidating the relationship between the physicochemical properties of aluminium-based adjuvants and their immunological mechanisms of action

Aluminium salts are by far the most commonly used adjuvants in vaccines. There are only two aluminium salts which are used in clinically-approved vaccines, Alhydrogel® and AdjuPhos®, while the novel aluminium adjuvant used in Gardasil® is a sulphated version of the latter. We have investigated the physicochemical properties of these two aluminium adjuvants and specifically in milieus approximating to both vaccine vehicles and the composition of injection sites. Additionally we have used a monocytic cell line to establish the relationship between their physicochemical properties and their internalisation and cytotoxicity. We emphasise that aluminium adjuvants used in clinically approved vaccines are chemically and biologically dissimilar with concomitantly potentially distinct roles in vaccine-related adverse events.