Specific and off-target immune responses following COVID-19 vaccination with ChAdOx1-S and BNT162b2 vaccines-an exploratory sub-study of the BRACE trial

BACKGROUND

The COVID-19 pandemic led to the rapid development and deployment of several highly effective vaccines against SARS-CoV-2. Recent studies suggest that these vaccines may also have off-target effects on the immune system. We sought to determine and compare the off-target effects of the adenovirus vector ChAdOx1-S (Oxford-AstraZeneca) and modified mRNA BNT162b2 (Pfizer-BioNTech) vaccines on immune responses to unrelated pathogens.

METHODS

Prospective sub-study within the BRACE trial. Blood samples were collected from 284 healthcare workers before and 28 days after ChAdOx1-S or BNT162b2 vaccination. SARS-CoV-2-specific antibodies were measured using ELISA, and whole blood cytokine responses to specific (SARS-CoV-2) and unrelated pathogen stimulation were measured by multiplex bead array.

FINDINGS

Both vaccines induced robust SARS-CoV-2 specific antibody and cytokine responses. ChAdOx1-S vaccination increased cytokine responses to heat-killed (HK) Candida albicans and HK Staphylococcus aureus and decreased cytokine responses to HK Escherichia coli and BCG. BNT162b2 vaccination decreased cytokine response to HK E. coli and had variable effects on cytokine responses to BCG and resiquimod (R848). After the second vaccine dose, BNT162b2 recipients had greater specific and off-target cytokine responses than ChAdOx1-S recipients.

INTERPRETATION

ChAdOx1-S and BNT162b2 vaccines alter cytokine responses to unrelated pathogens, indicative of potential off-target effects. The specific and off-target effects of these vaccines differ in their magnitude and breadth. The clinical relevance of these findings is uncertain and needs further study.

FUNDING

Bill & Melinda Gates Foundation, National Health and Medical Research Council, Swiss National Science Foundation and the Melbourne Children's. BRACE trial funding is detailed in acknowledgements.

The Prevalence of IgE-Mediated Food Allergy and Other Allergic Diseases in the First 10 Years: The Population-Based, Longitudinal HealthNuts Study

BACKGROUND

There are limited longitudinal data on the population prevalence of allergic conditions during childhood, and few studies have incorporated the reference standard oral food challenge to confirm food allergy.

OBJECTIVE

To describe the population prevalence of IgE-mediated food allergy, eczema, asthma, and rhinitis at ages 6 and 10 years in Melbourne, Australia.

METHODS

The HealthNuts study recruited 5,276 1-year-old infants in Melbourne, Australia, with repeat assessments at ages 6 and 10 years. At ages 6 and 10 years, carers completed a questionnaire on symptoms and doctor diagnosis of allergic conditions (International Study of Asthma and Allergies in Children). Children were invited to attend a clinic assessment including skin prick test, lung function tests, and oral food challenges when indicated. To minimize the impact of attrition bias, prevalence estimates among participants at ages 6 and 10 years were weighted to reflect characteristics of the whole cohort at recruitment.

RESULTS

In total, 4,455 and 4,065 families participated at ages 6 and 10 years, respectively (84% and 77% of the original cohort). Of those, 73% and 55% of participants ages 6 and 10 years, respectively, completed clinical assessments. Overall, 36.5% (95% CI, 34.8-38.2) and 38.2% (95% CI, 36.5-40.1%) of 6- and 10-year-olds had at least one current allergic disease, and around one third of those had two or more allergic diseases. Food allergy occurred in 6.4% (95% CI, 5.6-7.2) of 6-year olds and 6.3% (95% CI, 5.5-7.2) of 10-year-olds. Among infants with challenge-confirmed food allergy in infancy, 45% had persistent disease at age 10 years. The prevalence of current diagnosed asthma at ages 6 and 10 years were 12.1% (95% CI, 10.9-13.3) and 13.1% (95% CI, 11.9-14.4), respectively, current eczema decreased slightly from 15.3% (95% CI, 14.1-19.7) at age 6 years to 12.9% (95% CI, 11.7-14.2) at age 10 years, and current rhinitis increased from 15.1% (95% CI, 13.9-16.5) at age 6 years to 25.0% (95% CI, 23.4-26.7) at age 10 years.

CONCLUSIONS

Allergic diseases affect 40% of primary school-age children; one third have multiple allergic diagnoses. Challenge-confirmed food allergy prevalence remains high, and 45% of infants with food allergy have persistent disease to age 10 years.

The Human Health Impacts of the Red Imported Fire Ant in the Western Pacific Region Context: A Narrative Review

Background: The red imported fire ant (RIFA) is one of the world's most destructive invasive species. RIFA stings are painful and can lead to allergic reactions, including life-threatening anaphylaxis, yet health impacts remain inadequately defined. Methods: We searched MEDLINE (Ovid) and Google Scholar (grey literature) from inception until 20 September 2023 for articles in English using search terms related to red imported fire ants and allergies, including anaphylaxis. Results: Approximately a third of the population in RIFA-infested areas are stung each year. The most frequent reaction is a sterile 1-2 mm pseudo pustule on the skin. Approximately 20% of stings cause a large local reaction and between about 0.5% and 2% stings cause a systemic allergic reaction which can range from skin symptoms to life-threatening anaphylaxis. Local biodiversity is also significantly disrupted by invading RIFA and may lead to complex adverse effects on human health, from agriculture losses to expanded ranges for pathogen vectors. Conclusions: The potential for red imported fire ants to establish themselves as an invasive species in the Western Pacific presents a substantial and costly health issue. Successful eradication and surveillance programs, to identify and eradicate new incursions, would avoid substantial health impacts and costs.

A genome catalog of the early-life human skin microbiome

BACKGROUND

Metagenome-assembled genomes have greatly expanded the reference genomes for skin microbiome. However, the current reference genomes are largely based on samples from adults in North America and lack representation from infants and individuals from other continents.

RESULTS

Here we use deep shotgun metagenomic sequencing to profile the skin microbiota of 215 infants at age 2-3 months and 12 months who are part of the VITALITY trial in Australia as well as 67 maternally matched samples. Based on the infant samples, we present the Early-Life Skin Genomes (ELSG) catalog, comprising 9483 prokaryotic genomes from 1056 species, 206 fungal genomes from 13 species, and 39 eukaryotic viral sequences. This genome catalog substantially expands the diversity of species previously known to comprise human skin microbiome and improves the classification rate of sequenced data by 21%. The protein catalog derived from these genomes provides insights into the functional elements such as defense mechanisms that distinguish early-life skin microbiome. We also find evidence for microbial sharing at the community, bacterial species, and strain levels between mothers and infants.

CONCLUSIONS

Overall, the ELSG catalog uncovers the skin microbiome of a previously underrepresented age group and population and provides a comprehensive view of human skin microbiome diversity, function, and development in early life.

Australian Infant Food Allergy Emergency Presentations Following Updated Early Food Introduction Guidelines

BACKGROUND

The Australasian Society of Clinical Immunology and Allergy food allergy prevention guidelines were updated in 2016 to recommend home introduction of allergenic foods actively in the first year of life, including to infants at high risk of allergy. An important consideration for parents and providers is whether this practice increases food allergy reactions or anaphylaxis.

OBJECTIVE

We aimed to determine whether the 2016 update of food allergy prevention guidelines was associated with an increase in food allergy or anaphylaxis emergency department (ED) presentations.

METHODS

We obtained hospital electronic medical records for infants aged 4 to 12 months who attended the Royal Children's Hospital Melbourne ED in 2015 or in 2018 with a presenting problem or an encounter diagnosis of food allergy or anaphylaxis.

RESULTS

Emergency department presentations owing to food allergy increased from 1.0% (95% CI, 0.85-1.23) in 2015 to 1.4% (95% CI, 1.22-1.67) in 2018 (P = .006). There was no increase in the number of anaphylaxis presentations (28 in 2015 and 22 in 2018) or peanut anaphylaxis presentations (three in 2015 and three in 2018). Overall, the proportion of food allergy presentations attributed to IgE-mediated food allergy was similar (82.1% in 2015 and 84.1% in 2018), whereas peanut allergy presentations increased slightly, although not statically significantly, from 14.6% to 21.2% (P = .09). Food protein-induced enterocolitis syndrome ED presentations were five in 2015 (4.3%) and 12 in 2018(7.6%), although not statistically significant (P = .25).

CONCLUSIONS

Changes to food allergy prevention guidelines recommending the earlier introduction of allergenic food may have led to a small increase in ED presentations for food allergy but not anaphylaxis.

Bacillus Calmette-Guérin vaccination for protection against recurrent herpes labialis: a nested randomised controlled trial

Background

Recurrences of herpes simplex virus (HSV) in the orofacial region (herpes labialis or cold sores) impact quality-of-life. We aimed to study whether the bacille Calmette-Guérin (BCG) vaccine can attenuate cold sore recurrences through off-target immunomodulatory effects.

Methods

In this nested randomised controlled trial within the multicentre, phase 3 BRACE trial, 6828 healthcare workers were randomised in 36 sites in Australia, the Netherlands, Spain, the United Kingdom and Brazil, to receive BCG-Denmark or no BCG (1:1 ratio using a web-based procedure) and followed for 12 months with 3-monthly questionnaires. Exclusion criteria included contraindication to BCG vaccine or previous vaccination with BCG within the past year, any other live-attenuated vaccine within the last month, or any COVID-specific vaccine. The intervention group received one intradermal dose of 0.1 mL of BCG-Denmark corresponding to 2-8 x 105 colony forming units of Mycobacterium bovis, Danish strain 1331. The primary outcome was the difference in restricted mean survival time (i.e., time to first cold-sore recurrence), in participants with frequent recurrent herpes labialis (≥4 recurrences/year), analysed by intention-to-treat. Secondary outcomes addressed additional questions, including analyses in other sub-populations. Adverse events were monitored closely during the first 3 months and were reported in all participants who received one dose of study drug according to intervention received. The BRACE trial is registered with ClinicalTrials.gov, NCT04327206.

Findings

Between March 30, 2020 and February 18, 2021, 84 individuals with frequent recurrent cold sores were randomly assigned to BCG (n = 38) or control (n = 46). The average time to first cold-sore recurrence was 1.55 months longer in the BCG group (95% CI 0.27-2.82, p = 0.02) than the control group (hazard ratio 0.54, 95% CI 0.32-0.91; intention-to-treat). The beneficial effect of BCG was greater in the as-treated population (difference 1.91 months, 95% CI 0.69-3.12, p = 0.003; hazard ratio 0.45, 95% CI 0.26-0.76). In prespecified subgroup analyses, only sex modified the treatment effect (interaction p = 0.007), with benefit restricted to males. Over 12 months, a greater proportion of participants in the BCG group compared with the control group reported a decrease in duration (61% vs 21%), severity (74% vs 21%), frequency (55% vs 21%), and impact on quality of life (42% vs 15%) of cold sore recurrences. In participants who had ever had a cold sore, there was also a decrease in self-reported burden of recurrences in the BCG group. In participants who had never had a cold sore, there was an increased risk of a first episode in the BCG group (risk difference 1.4%; 95% CI 0.3-2.6%, p = 0.02). There were no safety concerns.

Interpretation

BCG-Denmark vaccination had a beneficial effect on herpes labialis, particularly in males with frequent recurrences, but may increase the risk of a first cold sore.

Funding

Bill & Melinda Gates Foundation, the Minderoo Foundation, Sarah and Lachlan Murdoch, the Royal Children's Hospital Foundation, Health Services Union NSW, the Peter Sowerby Foundation, SA Health, the Insurance Advisernet Foundation, the NAB Foundation, the Calvert-Jones Foundation, the Modara Pines Charitable Foundation, the UHG Foundation Pty Ltd, Epworth Healthcare, and individual donors.

Infant food allergy phenotypes and association with lung function deficits and asthma at age 6 years: a population-based, prospective cohort study in Australia

BACKGROUND

Food allergy is considered a precursor to asthma in the context of the atopic march, but the relationship between infant food allergy phenotypes and lung function and asthma in childhood is unclear. We aimed to examine the association between food sensitisation and challenge-confirmed food allergy in infancy, as well as persistent and resolved food allergy up to age 6 years, and the risk of lung function deficits and asthma at age 6 years.

METHODS

The longitudinal, population-based HealthNuts cohort study in Melbourne, VIC, Australia, recruited 5276 infants children aged 1 year who attended council-run immunisation sessions between Sept 28, 2007, and Aug 5, 2011. At age 1 year, all children completed skin prick testing to four food allergens (egg, peanut, sesame, and either shrimp or cow's milk) and an oral food challenge (egg, peanut, and sesame) at the Royal Children's Hospital in Melbourne. Parents completed questionnaires about their infant's allergy history, demographic characteristics, and environmental exposures. At age 6 years, children were invited for a health assessment that included skin prick testing for ten foods (milk, egg, peanut, wheat, sesame, soy, shrimp, cashew, almond, and hazelnut) and eight aeroallergens (alternaria, cladasporum, house dust mite, cat hair, dog hair, bermuda grass, rye grass, and birch mix), oral food challenges, and lung function testing by spirometry. Questionnaires completed by parents (different to those completed at age 1 year) captured the child's allergy and respiratory history and demographics. We investigated associations between food allergy phenotypes (food-sensitised tolerance or food allergy; and ever, transient, persistent, or late-onset food allergy), lung function spirometry measures (forced expiratory volume in 1 sec [FEV1] and forced vital capacity [FVC] z-scores, FEV1/FVC ratio, forced expiratory flow at 25% and 75% of the pulmonary volume [FEF25-75%], and bronchodilator responsiveness), and asthma using regression methods. Only children with complete data on the exposure, outcome, and confounders were included in models. Infants without food sensitisation or food allergy at age 1 year and 6 years served as the reference group.

FINDINGS

Of 5276 participants, 3233 completed the health assessment at age 6 years and were included in this analysis. Food allergy, but not food-sensitised tolerance, at age 1 year was associated with reduced FEV1 and FVC (aβ -0·19 [95% CI -0·32 to -0·06] and -0·17 [-0·31 to -0·04], respectively) at age 6 years. Transient egg allergy was associated with reduced FEV1 and FVC compared with never having egg allergy (-0·18 [95% CI -0·33 to -0·03] and -0·15 [-0·31 to 0·00], respectively), whereas persistent egg allergy was not (FEV1 -0·09 [-0·48 to 0·31]; FVC -0·20 [-0·62 to 0·21]). Transient peanut allergy was associated with reduced FEV1 and FVC (FEV1 aβ -0·37 [-0·79 to 0·04] and FVC aβ -0·55 [-0·98 to -0·12]), in addition to persistent peanut allergy (FEV1 aβ -0·30 [-0·54 to -0·06] and FVC aβ-0·30 [-0·55 to -0·05]), and late-onset peanut allergy (FEV1 aβ -0·62 [-1·06 to -0·18] and FVC aβ-0·49 [-0·96 to -0·03]). Estimates suggested that food-sensitised tolerance and food allergy were associated with reduced FEF25-75%, although some estimates were imprecise. Food allergy phenotypes were not associated with an FEV1/FVC ratio. Late-onset peanut allergy was the only allergy phenotype that was possibly associated with increased risk of bronchodilator responsiveness (2·95 [95% CI 0·77 to 11·38]). 430 (13·7%) of 3135 children were diagnosed with asthma before age 6 years (95% CI 12·5-15·0). Both food-sensitised tolerance and food allergy at age 1 year were associated with increased asthma risk at age 6 years (adjusted odds ratio 1·97 [95% CI 1·23 to 3·15] and 3·69 [2·81 to 4·85], respectively). Persistent and late-onset peanut allergy were associated with higher asthma risk (3·87 [2·39 to 6·26] and 5·06 [2·15 to 11·90], respectively).

INTERPRETATION

Food allergy in infancy, whether it resolves or not, is associated with lung function deficits and asthma at age 6 years. Follow-up studies of interventions to prevent food allergy present an opportunity to examine whether preventing these food allergies improves respiratory health.

FUNDING

National Health & Medical Research Council of Australia, Ilhan Food Allergy Foundation, AnaphylaxiStop, the Charles and Sylvia Viertel Medical Research Foundation, the Victorian Government's Operational Infrastructure Support Program.

BNT162b2 COVID-19 vaccination in children alters cytokine responses to heterologous pathogens and Toll-like receptor agonists

Background

Vaccines can have beneficial off-target (heterologous) effects that alter immune responses to, and protect against, unrelated infections. The heterologous effects of COVID-19 vaccines have not been investigated in children.

Aim

To investigate heterologous and specific immunological effects of BNT162b2 COVID-19 vaccination in children.

Methods

A whole blood stimulation assay was used to investigate in vitro cytokine responses to heterologous stimulants (killed pathogens, Toll-like receptor ligands) and SARS-CoV-2 antigens. Samples from 29 children, aged 5-11 years, before and 28 days after a second BNT162b2 vaccination were analysed (V2 + 28). Samples from eight children were analysed six months after BNT162b2 vaccination.

Results

At V2 + 28, interferon-γ and monocyte chemoattractant protein-1 responses to S. aureus, E. coli, L. monocytogenes, BCG vaccine, H. influenzae, hepatitis B antigen, poly(I:C) and R848 stimulations were decreased compared to pre-vaccination. For most of these heterologous stimulants, IL-6, IL-15 and IL-17 responses were also decreased. There were sustained decreases in cytokine responses to viral, but not bacterial, stimulants six months after BNT162b2 vaccination. Cytokine responses to irradiated SARS-CoV-2, and spike glycoprotein subunits (S1 and S2) were increased at V2 + 28 for most cytokines and remained higher than pre-vaccination responses 6 months after BNT162b2 vaccination for irradiated SARS-CoV-2 and S1. There was no correlation between BNT162b2 vaccination-induced anti-SARS-CoV2-receptor binding domain IgG antibody titre at V2 + 28 and cytokine responses.

Conclusions

BNT162b2 vaccination in children alters cytokine responses to heterologous stimulants, particularly one month after vaccination. This study is the first to report the immunological heterologous effects of COVID-19 vaccination in children.

Updated guidance regarding the risk of allergic reactions to COVID-19 vaccines and recommended evaluation and management: A GRADE assessment and international consensus approach

This guidance updates 2021 GRADE (Grading of Recommendations Assessment, Development and Evaluation) recommendations regarding immediate allergic reactions following coronavirus disease 2019 (COVID-19) vaccines and addresses revaccinating individuals with first-dose allergic reactions and allergy testing to determine revaccination outcomes. Recent meta-analyses assessed the incidence of severe allergic reactions to initial COVID-19 vaccination, risk of mRNA-COVID-19 revaccination after an initial reaction, and diagnostic accuracy of COVID-19 vaccine and vaccine excipient testing in predicting reactions. GRADE methods informed rating the certainty of evidence and strength of recommendations. A modified Delphi panel consisting of experts in allergy, anaphylaxis, vaccinology, infectious diseases, emergency medicine, and primary care from Australia, Canada, Europe, Japan, South Africa, the United Kingdom, and the United States formed the recommendations. We recommend vaccination for persons without COVID-19 vaccine excipient allergy and revaccination after a prior immediate allergic reaction. We suggest against >15-minute postvaccination observation. We recommend against mRNA vaccine or excipient skin testing to predict outcomes. We suggest revaccination of persons with an immediate allergic reaction to the mRNA vaccine or excipients be performed by a person with vaccine allergy expertise in a properly equipped setting. We suggest against premedication, split-dosing, or special precautions because of a comorbid allergic history.

Efficacy and safety of oral immunotherapy for peanut, cow's milk, and hen's egg allergy: A systematic review of randomized controlled trials

BACKGROUND

Oral immunotherapy (OIT) is a promising treatment for food allergies; however, safety is a concern. We synthesized evidence from the best randomized controlled trials (RCTs) on efficacy/safety of OIT for desensitization (DS) and remission (sustained unresponsiveness (SU)) in IgE mediated allergy to peanut, hen's eggs, and cow's milk. BODY: We searched Pubmed, EMBASE, and Cochrane databases (Until Oct 22) identifying 16 eligible RCTs published in English measuring food allergy by food challenge at the beginning and at the end of the study. The Cochrane Risk of Bias tool was used to assess study quality. We found 18 eligible studies. There was evidence of efficacy for DS for all allergens: peanut (RR 11.32; 95% CI 5.93, 21.60, I² 49%, 8 studies); hen's egg (RR 4.67; 2.66, 8.21, I² 0%, 5 studies); cow's milk (RR 13.98; 3.51, 55.65, I² 0%, 4 studies) and evidence for SU for peanut (RR 7.74; 2.90, 20.69, I² 0%, 3 studies) and hen's egg (RR 6.91; 1.67, 28.57, I² 0%, 2 studies). Allergic events were increased with intervention, and risk of adrenaline use increased for peanut RR 2.96; 1.63, 5.35, I² 0%, 8 studies; egg RR 1.71; 0.42, 6.92, I² 0%, 6 studies; and milk RR 8.45; 2.02, 35.27, I² 0%, 4 studies.

CONCLUSION

We found strong evidence that peanut, hen's egg, and cow's milk OIT can induce DS and some evidence for remission. There was a high risk of allergic reactions. Generalizability to the entire food allergic population is not known.

A genome catalog of the early-life human skin microbiome

Metagenome-assembled genomes have greatly expanded the reference genomes for skin microbiome. However, the current reference genomes are largely based on samples from adults in North America and lack representation from infants and individuals from other continents. Here we used ultra-deep shotgun metagenomic sequencing to profile the skin microbiota of 215 infants at age 2-3 months and 12 months who were part of the VITALITY trial in Australia as well as 67 maternally-matched samples. Based on the infant samples, we present the Early-Life Skin Genomes (ELSG) catalog, comprising 9,194 bacterial genomes from 1,029 species, 206 fungal genomes from 13 species, and 39 eukaryotic viral sequences. This genome catalog substantially expands the diversity of species previously known to comprise human skin microbiome and improves the classification rate of sequenced data by 25%. The protein catalog derived from these genomes provides insights into the functional elements such as defense mechanisms that distinguish early-life skin microbiome. We also found evidence for vertical transmission at the microbial community, individual skin bacterial species and strain levels between mothers and infants. Overall, the ELSG catalog uncovers the skin microbiome of a previously underrepresented age group and population and provides a comprehensive view of human skin microbiome diversity, function, and transmission in early life.

Phase 3 Trial of Epicutaneous Immunotherapy in Toddlers with Peanut Allergy

BACKGROUND

No approved treatment for peanut allergy exists for children younger than 4 years of age, and the efficacy and safety of epicutaneous immunotherapy with a peanut patch in toddlers with peanut allergy are unknown.

METHODS

We conducted this phase 3, multicenter, double-blind, randomized, placebo-controlled trial involving children 1 to 3 years of age with peanut allergy confirmed by a double-blind, placebo-controlled food challenge. Patients who had an eliciting dose (the dose necessary to elicit an allergic reaction) of 300 mg or less of peanut protein were assigned in a 2:1 ratio to receive epicutaneous immunotherapy delivered by means of a peanut patch (intervention group) or to receive placebo administered daily for 12 months. The primary end point was a treatment response as measured by the eliciting dose of peanut protein at 12 months. Safety was assessed according to the occurrence of adverse events during the use of the peanut patch or placebo.

RESULTS

Of the 362 patients who underwent randomization, 84.8% completed the trial. The primary efficacy end point result was observed in 67.0% of children in the intervention group as compared with 33.5% of those in the placebo group (risk difference, 33.4 percentage points; 95% confidence interval, 22.4 to 44.5; P<0.001). Adverse events that occurred during the use of the intervention or placebo, irrespective of relatedness, were observed in 100% of the patients in the intervention group and 99.2% in the placebo group. Serious adverse events occurred in 8.6% of the patients in the intervention group and 2.5% of those in the placebo group; anaphylaxis occurred in 7.8% and 3.4%, respectively. Serious treatment-related adverse events occurred in 0.4% of patients in the intervention group and none in the placebo group. Treatment-related anaphylaxis occurred in 1.6% in the intervention group and none in the placebo group.

CONCLUSIONS

In this trial involving children 1 to 3 years of age with peanut allergy, epicutaneous immunotherapy for 12 months was superior to placebo in desensitizing children to peanuts and increasing the peanut dose that triggered allergic symptoms. (Funded by DBV Technologies; EPITOPE ClinicalTrials.gov number, NCT03211247.).

Epigenomic variability is associated with age-specific naïve CD4 T cell response to activation in infants and adolescents

Childhood is a critical period of immune development. During this time, naïve CD4 (nCD4) T cells undergo programmed cell differentiation, mediated by epigenetic changes, in response to external stimuli leading to a baseline homeostatic state that may determine lifelong disease risk. However, the ontogeny of epigenetic signatures associated with CD4 T cell activation during key developmental periods are yet to be described. We investigated genome-wide DNA methylation (DNAm) changes associated with nCD4 T activation following 72 h culture in media+anti-CD3/CD28 beads in healthy infants (aged 12 months, n = 18) and adolescents (aged 10-15 years, n = 15). We integrated these data with transcriptomic and cytokine profiling from the same samples. nCD4 T cells from both age groups show similar extensive epigenetic reprogramming following activation, with the majority of genes involved in the T cell receptor signaling pathway associated with differential methylation. Additionally, we identified differentially methylated probes showing age-specific responses, that is, responses in only infants or adolescents, including within a cluster of T cell receptor (TCR) genes. These encoded several TCR alpha joining (TRAJ), and TCR alpha variable (TRAV) genes. Cytokine data analysis following stimulation revealed enhanced release of IFN-γ, IL-2 and IL-10, in nCD4 T cells from adolescents compared with infants. Overlapping differential methylation and cytokine responses identified four probes potentially underpinning these age-specific responses. We show that DNAm in nCD4T cells in response to activation is dynamic in infancy and adolescence, with additional evidence for age-specific effects potentially driving variation in cytokine responses between these ages.

Is antenatal or early-life vitamin D associated with eczema or food allergy in childhood? A systematic review

OBJECTIVE

To summarise the associations between antenatal or early-life blood vitamin D and the development of eczema/food allergy in childhood.

DESIGN

A systematic review and meta-analyses were conducted to synthesize the published literature. Two reviewers independently performed the study selection and data extraction on Covidence. We assessed the risk of bias for observational studies by using the Newcastle-Ottawa Scale and the Cochrane Risk of Bias tool for clinical trials. The certainty of the evidence was assessed using Grading of Recommendations, Assessment, Development and Evaluations (GRADE).

DATA SOURCES

We systematically searched PubMed and Embase from inception and April 2022.

ELIGIBILITY CRITERIA

Human studies that investigated prospective associations between antenatal or early-life blood vitamin D levels, dietary intake or supplementation and childhood eczema/food allergy.

RESULTS

Forty-three articles including six randomised controlled trials (RCTs) were included. Four RCTs of vitamin D supplementation during pregnancy showed no evidence of an effect on the incidence of eczema (pooled odds ratio [OR] = 0.85; 0.67-1.08, I2  = 6.7%, n = 2074). Three RCTs reported null associations between supplementation in pregnancy/infancy and food allergy. From six cohort studies, increasing cord blood vitamin D levels were associated with reduced prevalence of eczema at/close to age one (OR per 10 nmol/L increase = 0.89; 0.84-0.94, I2  = 0%, 2025 participants). We found no evidence of an association between maternal antenatal or infant vitamin D level or dietary intake and the development of food allergy or eczema in offspring.

CONCLUSIONS

We found an association between higher vitamin D levels in cord blood and reduced risk of eczema in cohort studies. Further trials with maternal and infant supplementation are needed to confirm if vitamin D supplementation can effectively prevent eczema or food allergy in childhood.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, No. CRD42013005559.

Randomized Trial of BCG Vaccine to Protect against Covid-19 in Health Care Workers

BACKGROUND

The bacille Calmette-Guérin (BCG) vaccine has immunomodulatory "off-target" effects that have been hypothesized to protect against coronavirus disease 2019 (Covid-19).

METHODS

In this international, double-blind, placebo-controlled trial, we randomly assigned health care workers to receive the BCG-Denmark vaccine or saline placebo and followed them for 12 months. Symptomatic Covid-19 and severe Covid-19, the primary outcomes, were assessed at 6 months; the primary analyses involved the modified intention-to-treat population, which was restricted to participants with a negative test for severe acute respiratory syndrome coronavirus 2 at baseline.

RESULTS

A total of 3988 participants underwent randomization; recruitment ceased before the planned sample size was reached owing to the availability of Covid-19 vaccines. The modified intention-to-treat population included 84.9% of the participants who underwent randomization: 1703 in the BCG group and 1683 in the placebo group. The estimated risk of symptomatic Covid-19 by 6 months was 14.7% in the BCG group and 12.3% in the placebo group (risk difference, 2.4 percentage points; 95% confidence interval [CI], -0.7 to 5.5; P = 0.13). The risk of severe Covid-19 by 6 months was 7.6% in the BCG group and 6.5% in the placebo group (risk difference, 1.1 percentage points; 95% CI, -1.2 to 3.5; P = 0.34); the majority of participants who met the trial definition of severe Covid-19 were not hospitalized but were unable to work for at least 3 consecutive days. In supplementary and sensitivity analyses that used less conservative censoring rules, the risk differences were similar but the confidence intervals were narrower. There were five hospitalizations due to Covid-19 in each group (including one death in the placebo group). The hazard ratio for any Covid-19 episode in the BCG group as compared with the placebo group was 1.23 (95% CI, 0.96 to 1.59). No safety concerns were identified.

CONCLUSIONS

Vaccination with BCG-Denmark did not result in a lower risk of Covid-19 among health care workers than placebo. (Funded by the Bill and Melinda Gates Foundation and others; BRACE ClinicalTrials.gov number, NCT04327206.).

Effectiveness of Intranasal Mometasone Furoate vs Saline for Sleep-Disordered Breathing in Children: A Randomized Clinical Trial

Importance

Obstructive sleep-disordered breathing (SDB) in children is characterized by snoring and difficulty breathing during sleep. SDB affects at least 12% of otherwise healthy children and is associated with significant morbidity. Evidence from small clinical trials suggests that intranasal corticosteroids improve SDB as measured by polysomnography; however, the effect on symptoms and quality of life is unclear.

Objective

To determine whether intranasal mometasone furoate is more effective than intranasal saline for improving symptoms and quality of life in children with SDB.

Design, Setting, and Participants

The MIST trial was a multicenter, randomized, double-blind, placebo-controlled trial, recruiting participants from June 8, 2018, to February 13, 2020. Children aged 3 to 12 years who were referred to a specialist for significant SDB symptoms were included; exclusions were previous adenotonsillectomy, body mass index greater than the 97th percentile, and severe SDB. Randomization was stratified by site, and data were analyzed on an intention-to-treat basis from October 28, 2020, to September 25, 2022.

Interventions

Participants were randomly assigned to receive mometasone furoate, 50 μg, or sodium chloride (saline), 0.9%, 1 spray per nostril daily, dispensed in identical bottles.

Main Outcomes and Measures

The primary outcome was resolution of significant SDB symptoms (ie, reduction to a level no longer requiring referral to a specialist as per the American Academy of Pediatrics guidelines) at 6 weeks, measured by parental report of symptoms using the SDB Score.

Results

A total of 276 participants (mean [SD] age, 6.1 [2.3] years; 146 male individuals [53%]) were recruited, 138 in each treatment arm. Resolution of significant SDB symptoms occurred in 56 of 127 participants (44%) in the mometasone group and 50 of 123 participants (41%) in the saline group (risk difference, 4%; 95% CI, -8% to 16%; P = .51) with 26 participants lost to follow-up and missing values managed by multiple imputation. The main adverse effects were epistaxis, affecting 12 of 124 participants (9.7%) in the mometasone group and 18 of 120 participants (15%) in the saline group, and nasal itch/irritation, affecting 12 of 124 participants (9.7%) in the mometasone group and 22 of 120 participants (18%) in the saline group.

Conclusions and Relevance

Results of this randomized clinical trial suggest that there was no difference in treatment effect between intranasal mometasone and saline for the management of SDB symptoms. The results suggest that almost one-half of children with SDB could be initially managed in the primary care setting and may not require referral to specialist services, as is currently recommended.

Trial Registration

Australian New Zealand Clinical Trials Registry: ANZCTRN12618000448246.

TreEAT trial: Protocol for a randomized controlled trial investigating the efficacy and safety of early introduction of tree nuts for the prevention of tree nut allergy in infants with peanut allergy

INTRODUCTION

Children with peanut allergy are at increased risk of developing tree nut allergies, which can be severe and for most lifelong. Introduction of peanut in the first year of life can reduce the risk of peanut allergy; however, prevention strategies for tree nut allergies have not been established. We aimed to test the efficacy and safety of a novel strategy, a supervised multi-nut oral food challenge (OFC) compared with standard care for tree nut allergy prevention in infants at high risk of developing tree nut allergy, TreEAT.

METHODS AND ANALYSIS

TreEAT is a 2-armed, open-label, randomized, controlled trial (RCT). Infants (n = 212) aged 4-11 months with peanut allergy will be randomized 1:1 at peanut allergy diagnosis to either a hospital-based multi-tree nut (almond, cashew, hazelnut, and walnut) OFC using multi-nut butter or standard care (home introduction of individual tree nuts). All infants will be assessed at age 18 months, with questionnaires and SPT to peanut and tree nuts. Peanut and tree nut OFCs will be performed as required to determine the allergy status for each nut. The primary outcome is tree nut allergy at age 18 months. Secondary outcomes include peanut allergy resolution, proportion, and severity of adverse events related to tree nut ingestion, number and frequency of tree nuts ingested, quality of life and parental anxiety, and allergy-related healthcare visits from randomization to 18 months of age. Analyses will be performed on an intention-to-treat basis.

ETHICS AND DISSEMINATION

TreEAT was approved by the Royal Children's Hospital Human Research Ethics Committee (#70489). Outcomes will be presented at scientific conferences and disseminated through publication.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov ID: NCT04801823.

Out-of-hospital health care costs of childhood food allergy in Australia: A population-based longitudinal study

BACKGROUND

Australia has one of the highest prevalence of childhood food allergy in the world, but there are no data on its economic burden in Australia.

METHODS

We used data from the HealthNuts study, a population-based longitudinal study undertaken in Melbourne, Australia. Infants were recruited at age 12 months between Sept 2007 and Aug 2011 with food allergy diagnosed using oral food challenges. Health care costs of out-of-hospital services were collected through data linkage to Australia's universal health insurance scheme Medicare. Two-part model was used to compare costs after controlling for potential confounders.

RESULTS

2919 children were included, and 390 (13.4%) had challenge-confirmed food allergy at age 1 year. Compared with children without food allergy, children with food allergy had significantly higher costs for GP visits, specialist visits, tests, and prescriptions in the first four years of life. The total Medicare cost associated with food allergy from age 1 to 4 years was estimated to be AUD$889.7 (95% CI $566.1-$1188.3) or €411.0 (95% CI €261.5-€549.0) per child. This was projected into an annual Medicare cost of AUD$26.1 million (95% CI $20.1-$32.3 million) or €12.1 (95% CI €9.3-€14.9 million) based on population size in 2020.

CONCLUSIONS

Childhood food allergy causes considerable Medicare costs for out-of-hospital services in the first four years after birth in Australia. These findings can help anticipate the financial impact on the health care system associated with childhood food allergy, act as a useful costing resource for future evaluations, and inform management of childhood food allergy internationally.

Immuno-epigenomic analysis identifies attenuated interferon responses in naïve CD4 T cells of adolescents with peanut and multi-food allergy

BACKGROUND

IgE-mediated food allergies have been linked to suboptimal naïve CD4 T (nCD4T) cell activation in infancy, underlined by epigenetic and transcriptomic variation. Similar attenuated nCD4T cell activation in adolescents with food allergy have also been reported, but these are yet to be linked to specific epigenetic or transcriptional changes.

METHODS

We generated genome-wide DNA methylation data in purified nCD4 T cells at quiescence and following activation in a cohort of adolescents (aged 10-15 years old) with peanut allergy (peanut only or peanut + ≥1 additional food allergy) (FA, n = 29), and age-matched non-food allergic controls (NA, n = 18). Additionally, we assessed transcriptome-wide gene expression and cytokine production in these cells following activation.

RESULTS

We found widespread changes in DNA methylation in both NA and FA nCD4T cells in response to activation, associated with the T cell receptor signaling pathway. Adolescents with FA exhibit unique DNA methylation signatures at quiescence and post-activation at key genes involved in Th1/Th2 differentiation (RUNX3, RXRA, NFKB1A, IL4R), including a differentially methylated region (DMR) at the TNFRSF6B promoter, linked to Th1 proliferation. Combined analysis of DNA methylation, transcriptomic data and cytokine output in the same samples identified an attenuated interferon response in nCD4T cells from FA individuals following activation, with decreased expression of several interferon genes, including IFN-γ and a DMR at a key downstream gene, BST2.

CONCLUSION

We find that attenuated nCD4T cell responses from adolescents with food allergy are associated with specific epigenetic variation, including disruption of interferon responses, indicating dysregulation of key immune pathways that may contribute to a persistent FA phenotype. However, we recognize the small sample size, and the consequent restraint on reporting adjusted p-value statistics as limitations of the study. Further study is required to validate these findings.

The role of short-term grass pollen exposure in food skin-prick test reactivity, food allergy, and eczema flares in children

BACKGROUND

While the relationship between pollen and respiratory allergies is well-documented, the role of short-term pollen exposure in food allergy and eczema flares has not previously been explored. We aimed to investigate these associations in a population-based sample of children.

METHODS

We investigated 1- (n = 1108) and 6-year-old (n = 675) children in the grass pollen season from the HealthNuts cohort. Grass pollen concentrations were considered on the day of testing (lag 0), up to three days before (lag 1-lag 3) and cumulatively (lag 0-3). Associations between grass pollen and food skin-prick test reactivity (SPT ≥ 2 mm at age 1 year and ≥ 3 mm at age 6 years), eczema flares, challenge-confirmed food allergy, reaction threshold to oral food challenges (OFC), and serum food-specific IgE levels were analyzed using either logistic or quantile regression models. Atopy and family history of allergic disease were considered as potent effect modifiers.

RESULTS

Grass pollen at lag 0-3 (every 20 grains/m³ increase) was associated with an up to 1.2-fold increased odds of food SPT reactivity and eczema flares in 6-year-olds. In 1-year-olds, the associations were only observed for peanut in those with a family history of food allergy. Increasing grass pollen concentrations were associated with a lower reaction threshold to OFC and higher serum IgE levels in peanut-allergic 1-year-olds only.

CONCLUSION

Increasing grass pollen concentration was associated with increased risk of food SPT reactivity and eczema flares in children. The associations in peanut-allergic infants may be related to immune activation and/or peanut and grass pollen cross-reactivity leading to a lower reaction threshold.

A pragmatic approach to infant feeding for food allergy prevention

Early introduction of allergenic foods into an infant's diet is currently the most promising strategy to prevent food allergy, with infant guidelines around the world shifting from promoting avoidance to actively encourage the introduction of allergenic foods in the infant diet. Infant feeding guidelines vary according to regional public health priorities, and knowledge gaps remain, resulting in ongoing challenges for clinicians and families to translate guidelines into practical strategies for the introduction of complementary foods for food allergy prevention. Evidence from Australia demonstrates high community support and uptake of revised guidelines with most parents introducing allergenic foods in the first year of life, although this has not had the expected impact on substantially reducing food allergy prevalence. To uptake of guidelines from other countries is less clear, and several barriers have been noted in infant feeding RCTs, which may warrant intervention strategies. Further research is needed to understand additional strategies for food allergy prevention, particularly in infants who develop food allergy prior to when they are developmentally ready to commence solids. Several RCTs are underway investigating preventative strategies that target the window before allergen ingestion, such as vitamin D supplementation, emollient use, and immunizations that prime the immune response away from a Th2-driven allergic phenotype. Further research is also needed to understand the role of the environment and the host environment in the development of tolerance to foods.

Mode of Birth Is Not Associated With Food Allergy Risk in Infants

BACKGROUND

The association between mode of delivery and the risk of food allergy remains unclear due to the absence of studies with both challenge-proven food allergy outcomes and detailed information on the type of caesarean delivery.

OBJECTIVE

We assessed whether emergency or elective caesarean, or caesarean delivery in the presence or absence of labor initiation, is associated with the risk of food allergy.

METHODS

The HealthNuts study recruited 5276 12-month-old infants who underwent skin prick testing and oral food challenge to ascertain food allergy status, and linked the child's study data to additional birth data from the Victorian Perinatal Data Collection.

RESULTS

Parents of 3006 children consented to data linkage, and birth data were obtained on 2045. In this subgroup, 30% were born by caesarean and 13% had food allergy. Caesarean delivery, compared with vaginal birth, was not associated with the risk of food allergy (adjusted odds ratio [aOR]: 0.95, 95% confidence interval [CI]: 0.70, 1.30). Neither caesarean delivery before the onset of labor, nor after the onset of labor, was associated with the risk of food allergy (aOR: 0.83, 95% CI: 0.55-1.23 and aOR: 1.13, 95% CI: 0.75-1.72, respectively). Delivery by elective or emergency caesarean, compared with vaginal delivery, was not associated with risk of food allergy (aOR: 1.05, 95% CI: 0.71-1.55 and aOR: 0.86, 95% CI: 0.56-1.31). There was no evidence of effect modification by breastfeeding, older siblings, pet dog ownership, or maternal allergy.

CONCLUSION

Caesarean delivery, either with or without labor, or elective or emergency, was not associated with the risk of food allergy in a population-based cohort of 12-month-old infants.

An International First: Stakeholder Consensus Statement for Food Allergen Management in Packaged Foods and Food Service for Australia and New Zealand

Food-allergic consumers encounter inadequate, confusing, and ambiguous allergen information for packaged and unpackaged foods. Key Australian and New Zealand allergy organizations convened multiple forums to facilitate discussions among consumers, food manufacturers, food retailers, regulatory bodies, researchers, and health professionals to develop a unified approach to improving food allergen management. The following stakeholder consensus statement provides a foundation for advocacy for improved food allergen management and safety. It is the responsibility of consumers to: 1. declare their food allergies and read food labels (including ingredient lists and allergen declaration statements), and 2. ultimately make their own judgment about the foods they choose to consume. We consider that to enable consumers to make informed decisions about their safety, It is the responsibility of packaged food manufacturers to: 1. follow robust allergen management practices including quantitative risk assessment, and 2. use clear, consistent labeling to inform consumers about that food's allergen content, including the possible presence of unintended allergens. It is the responsibility of food service establishments and providers to: 1. follow robust allergen management practices, and 2. ensure that staff understand and can inform consumers about the allergen content of the food they provide, including the possible presence of unintended allergens.

Ana o 3 sIgE and diagnostic algorithms reduce cost of cashew allergy diagnosis in children compared with skin prick test: A cost comparison analysis

BACKGROUND

In the absence of a clear clinical history of reaction, diagnosis of cashew allergy using skin prick tests (SPT) or cashew-specific IgE requires a high number of oral food challenges (OFC). By using Ana o 3 sIgE alone, or a two-step diagnostic algorithm using cashew sIgE followed by Ana o 3 sIgE, there is a reduced need for OFC. We aimed to perform a cost comparison for both of these approaches compared with cashew SPT alone.

METHODS

Pooled individual-level data from 6 studies were used to determine diagnostic accuracy and OFC rate. Two studies used cashew SPT (n = 567, 198 allergic), with 95% positive and negative predictive values of ≥12 mm and <3 mm. Four studies were included in the pathways for Ana o 3 sIgE alone or a 2-step algorithm incorporating cashew and Ana o 3 sIgE (n = 271, 156 allergic). Cut-offs used were ≥8.5kUA/L and ≤0.1kUA/L for cashew sIgE and ≥0.35kUA/L and ≤0.1kUA/L for Ana o 3 sIgE. Costs were constructed based on unit prices from hospital inpatient admissions, expenses incurred by families, individual patient data on allergic reaction types and rates, and adrenaline autoinjector carriage, applying a health system perspective.

RESULTS

Modeled data through the Ana o 3 pathway resulted in a 46.43% cost reduction (€307,406/1000 patients) compared with using cashew SPT alone (€573,854/1000 patients). The 2-step algorithm resulted in a 44.94% cost reduction compared with SPT alone (€315,952.82/1000 patients). Both the Ana o 3 pathway and 2-step algorithm resulted in a 79%-80% reduction in OFCs compared with SPT.

CONCLUSIONS

Using Ana o 3 as a standalone test for cashew allergy diagnosis or a 2-step algorithm incorporating cashew sIgE and Ana o 3 sIgE is accurate and results in a large reduction in both OFCs and health system costs compared with cashew SPT alone.

Association Between Earlier Introduction of Peanut and Prevalence of Peanut Allergy in Infants in Australia

IMPORTANCE

Randomized clinical trials showed that earlier peanut introduction can prevent peanut allergy in select high-risk populations. This led to changes in infant feeding guidelines in 2016 to recommend early peanut introduction for all infants to reduce the risk of peanut allergy.

OBJECTIVE

To measure the change in population prevalence of peanut allergy in infants after the introduction of these new guidelines and evaluate the association between early peanut introduction and peanut allergy.

DESIGN

Two population-based cross-sectional samples of infants aged 12 months were recruited 10 years apart using the same sampling frame and methods to allow comparison of changes over time. Infants were recruited from immunization centers around Melbourne, Australia. Infants attending their 12-month immunization visit were eligible to participate (eligible age range, 11-15 months), regardless of history of peanut exposure or allergy history.

EXPOSURES

Questionnaires collected data on demographics, food allergy risk factors, peanut introduction, and reactions.

MAIN OUTCOME AND MEASURES

All infants underwent skin prick tests to peanut and those with positive results underwent oral food challenges. Prevalence estimates were standardized to account for changes in population demographics over time.

RESULTS

This study included 7209 infants (1933 in 2018-2019 and 5276 in 2007-2011). Of the participants in the older vs more recent cohort, 51.8% vs 50.8% were male; median (IQR) ages were 12.5 (12.2-13.0) months vs 12.4 (12.2-12.9) months. There was an increase in infants of East Asian ancestry over time (16.5% in 2018-2019 vs 10.5% in 2007-2011), which is a food allergy risk factor. After standardizing for infant ancestry and other demographics changes, peanut allergy prevalence was 2.6% (95% CI, 1.8%-3.4%) in 2018-2019, compared with 3.1% in 2007-2011 (difference, -0.5% [95% CI, -1.4% to 0.4%]; P = .26). Earlier age of peanut introduction was significantly associated with a lower risk of peanut allergy among infants of Australian ancestry in 2018-2019 (age 12 months compared with age 6 months or younger: adjusted odds ratio, 0.08 [05% CI, 0.02-0.36]; age 12 months compared with 7 to less than 10 months: adjusted odds ratio, 0.09 [95% CI, 0.02-0.53]), but not significant among infants of East Asian ancestry (P for interaction = .002).

CONCLUSIONS AND RELEVANCE

In cross-sectional analyses, introduction of a guideline recommending early peanut introduction in Australia was not associated with a statistically significant lower or higher prevalence of peanut allergy across the population.

PrEggNut Study: protocol for a randomised controlled trial investigating the effect of a maternal diet rich in eggs and peanuts from <23 weeks' gestation during pregnancy to 4 months' lactation on infant IgE-mediated egg and peanut allergy outcomes

INTRODUCTION

Clinical studies supported by immunological data indicate early life intervention strategies to be promising in reducing the growing global burden of food allergies. The events that predispose to food allergy, including the induction of allergen-specific immune responses, appear to be initiated early in development. Early exposure to food allergens in utero and via breast milk is likely to be important in initiating oral tolerance. We aim to determine the effectiveness of higher maternal food allergen consumption during pregnancy and lactation on infant food allergy outcomes.

METHODS AND ANALYSIS

This is a multisite, parallel, two-arm (1:1 allocation), single-blinded (outcome assessors, statistical analyst and investigators), randomised controlled trial. Pregnant women (<23 weeks' gestation) whose (unborn) infants have at least two biological family members (mother, father or siblings) with medically diagnosed allergic disease are eligible to participate. After obtaining written informed consent, pregnant women are randomised to either a high egg and peanut diet (at least 6 eggs and 60 peanuts per week) or standard (low) egg and peanut diet (no more than 3 eggs and 30 peanuts per week). The women are asked to follow their allocated diet from <23 weeks' gestation to 4 months' lactation. The primary outcome is food challenge proven IgE-mediated egg and/or peanut allergy in the infants at 12 months of age. Key secondary outcomes include infant sensitisation to egg and/or peanut and infant eczema. Our target sample size is 2136 women. Analyses will be performed on an intention-to-treat basis according to a pre-specified statistical analysis plan.

ETHICS AND DISSEMINATION

Ethical approval has been granted from the Women's and Children's Health Network Human Research Ethics Committee (approval number HREC/18/WCHN/42). Trial results will be presented at scientific conferences and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry ACTRN12618000937213.

The natural history of peanut and egg allergy in children up to age 6 years in the HealthNuts population-based longitudinal study

BACKGROUND

Prospectively collected data on the natural history of food allergy are lacking.

OBJECTIVE

We examined the natural history of egg and peanut allergy in children from age 1 to 6 years and assessed whether a skin prick test (SPT) result or other clinical factors at diagnosis are associated with the persistence or resolution of food allergy in early childhood.

METHODS

The HealthNuts cohort consists of 5276 children who were recruited at age 1 year and have been followed prospectively. Children with food allergy at age 1 year (peanut [n = 156] or raw egg [n = 471] allergy ) and children who developed new sensitizations or food reactions after age 1 year were assessed for food sensitization and allergy (confirmed by oral food challenge when indicated) at the 6-year follow-up.

RESULTS

New-onset food allergy developed by age 6 years was more common for peanut (0.7% [95% CI = 0.5%-1.1%]) than egg (0.09% [95% CI = 0.03%-0.3%]). Egg allergy resolved more commonly (89% [95% CI = 85%-92%]) than peanut allergy (29% [95% CI = 22%-38%]) by age 6 years. The overall weighted prevalence of peanut allergy at age 6 years was 3.1% (95% CI = 2.6-3.7%) and that of egg allergy was 1.2% (95% = CI 0.9%-1.6%). The factors at age 1 year associated with persistence of peanut allergy were peanut SPT result of 8 mm or larger (odds ratio [OR] = 2.35 [95% CI 1.08-5.12]), sensitization to tree nuts (adjusted OR [aOR] = 2.51 [95% CI = 1.00-6.35]), and early-onset severe eczema (aOR = 3.23, [95% CI 1.17-8.88]). Factors at age 1 associated with persistence of egg allergy at age 6 were egg SPT result of 4 mm or larger (OR = 2.98 [95% CI 1.35-6.36]), other (peanut and/or sesame) food sensitizations (aOR = 2.80 [95% CI = 1.11-7.03]), baked egg allergy (aOR = 7.41 [95% CI = 2.16-25.3]), and early-onset severe eczema (aOR = 3.77 [95% CI = 1.35-10.52]).

CONCLUSION

Most egg allergy and nearly one-third of peanut allergy resolves naturally by age 6 years. The prevalence of peanut allergy at age 6 years was similar to that observed at age 1 year, largely owing to new-onset food peanut allergy after age 1 year. Infants with early-onset eczema, larger SPT wheals, or multiple food sensitizations and/or allergies were less likely to acquire tolerance to either peanut or egg.

Climate change and global health: A call to more research and more action

There is increasing understanding, globally, that climate change and increased pollution will have a profound and mostly harmful effect on human health. This review brings together international experts to describe both the direct (such as heat waves) and indirect (such as vector-borne disease incidence) health impacts of climate change. These impacts vary depending on vulnerability (i.e., existing diseases) and the international, economic, political, and environmental context. This unique review also expands on these issues to address a third category of potential longer-term impacts on global health: famine, population dislocation, and environmental justice and education. This scholarly resource explores these issues fully, linking them to global health in urban and rural settings in developed and developing countries. The review finishes with a practical discussion of action that health professionals around the world in our field can yet take.

The association between environmental greenness and the risk of food allergy: A population-based study in Melbourne, Australia

BACKGROUND

While exposure to environmental greenness in childhood has shown mixed associations with the development of allergic disease, the relationship with food allergy has not been explored. We investigated the association between exposure to environmental greenness and challenge-confirmed food allergy in a large population-based cohort.

METHODS

The HealthNuts study recruited 5276 12-month-old infants in Melbourne, Australia, who underwent skin prick testing to peanut, egg, and sesame; infants with a detectable wheal underwent food challenges to determine food allergy status. Environmental greenness was estimated using the normalized difference vegetation index (NDVI) for five buffer zones around the infant's home address: at the home, 100 m, 500 m, 800 m, and 1600 m radial distances. Environmental greenness was categorized into 3 tertiles and mixed effects logistic regression models quantified the association between greenness and the risk of food allergy, adjusting for confounding and accounting for clustering at the neighborhood level.

RESULTS

NDVI data were available for n = 5097. For most buffer zones, medium and high greenness, compared to low greenness, was associated with an increased risk of peanut allergy (eg, 100 m tertile 2 aOR 1.89 95% CI 1.22-2.95, tertile 3 aOR 1.78 95% CI 1.13-2.82). For egg allergy, the effect sizes were smaller (100 m tertile 2 aOR 1.52 95% CI 1.16-1.97, tertile 3 aOR 1.38 95% CI 1.05-1.82). Socioeconomic status (SES) modified the association between greenness and peanut allergy, but not egg allergy; associations were apparent in the low SES group but not in the high SES group (p for interaction 0.08 at 100 m). Air pollution (PM2.5) also modified the associations between environmental greenness and food allergy, with associations present in high air pollution areas but not low (p for interaction at 100 m 0.05 for peanut and 0.06 for egg allergy.) CONCLUSION: Increased exposure to environmental greenness in the first year of life was associated with an increased risk of food allergy. Increased greenness may correlate with higher pollen levels which may trigger innate immune responses skewing the immune system to the Th2-dependent allergic phenotype; additionally, some pollen and food allergens are cross-reactive. Given the mixed data on greenness and other allergies, the relationship appears complex and may also be influenced by confounding variables outside those that were measured in this study.

Ana o 3 sIgE testing increases the accuracy of cashew allergy diagnosis using a two-step model

BACKGROUND

Measurement of cashew-specific IgE (sIgE) is often used to confirm sensitization but does not reliably diagnose clinical allergy. Ana o 3 is the dominant cashew allergen detected in 75-100% of patients with cashew allergy but not currently used in clinical practice.

OBJECTIVES

To determine if component-resolved diagnostics using specific IgE to the 2 S albumin from cashew, Ana o 3, improves the accuracy of diagnosing cashew allergy, thereby circumventing the need for an oral food challenge (OFC) in some patients.

METHODS

A population-based sample of 5276 children was recruited at age 1 year and followed up at age 6 years. Children with positive cashew skin prick test at age 6 underwent an OFC to clarify allergy status. Forty-seven children (mean age 5.02 ± 0.2) (33 cashew-allergic and 14 cashew-tolerant) had cashew sIgE and Ana o 3 sIgE quantified by ImmunoCAP System FEIA.

RESULTS

A cutoff of >0.32 kUA/L for Ana o 3 sIgE provided 95% specificity and 90% sensitivity and correctly identified 90% of clinical cashew allergy. At the same specificity, the sensitivity for cashew sIgE (>8.5 kUA/L) was only 26%. Sequential measurement of cashew sIgE followed by Ana o 3 sIgE diagnosed 90% of children with cashew allergy without the need for an OFC.

CONCLUSION

Ana o 3 sIgE testing provides higher diagnostic accuracy than cashew sIgE. Sequential measurement of cashew sIgE followed by Ana o 3 removed the need for a food challenge from 66% down to 12.8% (5-fold) of children compared with cashew sIgE testing alone.

Advances, Practical Implementation, and Unmet Needs Regarding Oral Immunotherapy for Food Allergy

Treatment of food allergy is a rapidly changing landscape, with arguably, the most significant advancement in recent years, the transition of oral immunotherapy (OIT) to clinical practice. As an innovation, OIT is a phase of rapidly increasing demand, particularly for some allergens such as peanut, egg, and milk, which have substantial evidence of efficacy. However, significant questions remain about how to best treat multiple food allergies and less common food allergies and how to optimize long-term safety and efficacy. This review summarizes the currently available resources for integrating food allergy OIT into clinical practice and focuses on the multiple remaining unmet needs such as providing an approach for OIT to food allergens for which there is no or limited evidence; practical issues related to food allergy treatment particularly when it is not going well; long-term outcomes and follow-up after OIT; and strategies to help meet the impending increase in demand.

Food allergy across the globe

The prevalence of food allergy (FA) is increasing in some areas of the globe, highlighting the need for better strategies for prevention, diagnosis, and therapy. In the last few decades, we have made great strides in understanding the causes and mechanisms underlying FAs, prompting guideline updates. Earlier guidelines recommended avoidance of common food allergens during pregnancy and lactation and delaying the introduction of allergenic foods in children aged between 1 and 3 years. Recent guidelines for allergy prevention recommend consumption of a healthy and diverse diet without eliminating or increasing the consumption of allergenic foods during pregnancy or breast-feeding. Early introduction of allergenic foods is recommended by most guidelines for allergy prevention after a period of exclusive breast-feedng (6 months [World Health Organization] or 4 months [European Academy of Allergy and Clinical Immunology]). New diagnostics for FA have been developed with varied availability of these tests in different countries. Finally, the first oral immunotherapy drug for FA was approved by the US Food and Drug Administration and European Medicines Agency in 2020. In this review, we will address the global prevalence of FA, our current understanding of the causes of FA, and the latest guidelines for preventing, diagnosing, and treating FA. We will also discuss similarities and differences between FA guidelines.

BCG vaccination to reduce the impact of COVID-19 in healthcare workers: Protocol for a randomised controlled trial (BRACE trial)

INTRODUCTION

BCG vaccination modulates immune responses to unrelated pathogens. This off-target effect could reduce the impact of emerging pathogens. As a readily available, inexpensive intervention that has a well-established safety profile, BCG is a good candidate for protecting healthcare workers (HCWs) and other vulnerable groups against COVID-19.

METHODS AND ANALYSIS

This international multicentre phase III randomised controlled trial aims to determine if BCG vaccination reduces the incidence of symptomatic and severe COVID-19 at 6 months (co-primary outcomes) compared with no BCG vaccination. We plan to randomise 10 078 HCWs from Australia, The Netherlands, Spain, the UK and Brazil in a 1:1 ratio to BCG vaccination or no BCG (control group). The participants will be followed for 1 year with questionnaires and collection of blood samples. For any episode of illness, clinical details will be collected daily, and the participant will be tested for SARS-CoV-2 infection. The secondary objectives are to determine if BCG vaccination reduces the rate, incidence, and severity of any febrile or respiratory illness (including SARS-CoV-2), as well as work absenteeism. The safety of BCG vaccination in HCWs will also be evaluated. Immunological analyses will assess changes in the immune system following vaccination, and identify factors associated with susceptibility to or protection against SARS-CoV-2 and other infections.

ETHICS AND DISSEMINATION

Ethical and governance approval will be obtained from participating sites. Results will be published in peer-reviewed open-access journals. The final cleaned and locked database will be deposited in a data sharing repository archiving system.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04327206.

The Risk of Allergic Reaction to SARS-CoV-2 Vaccines and Recommended Evaluation and Management: A Systematic Review, Meta-Analysis, GRADE Assessment, and International Consensus Approach

Concerns for anaphylaxis may hamper severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunization efforts. We convened a multidisciplinary group of international experts in anaphylaxis composed of allergy, infectious disease, emergency medicine, and front-line clinicians to systematically develop recommendations regarding SARS-CoV-2 vaccine immediate allergic reactions. Medline, EMBASE, Web of Science, the World Health Organizstion (WHO) global coronavirus database, and the gray literature (inception, March 19, 2021) were systematically searched. Paired reviewers independently selected studies addressing anaphylaxis after SARS-CoV-2 vaccination, polyethylene glycol (PEG) and polysorbate allergy, and accuracy of allergy testing for SARS-CoV-2 vaccine allergy. Random effects models synthesized the data to inform recommendations based on the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach, agreed upon using a modified Delphi panel. The incidence of SARS-CoV-2 vaccine anaphylaxis is 7.91 cases per million (n = 41,000,000 vaccinations; 95% confidence interval [95% CI] 4.02-15.59; 26 studies, moderate certainty), the incidence of 0.15 cases per million patient-years (95% CI 0.11-0.2), and the sensitivity for PEG skin testing is poor, although specificity is high (15 studies, very low certainty). We recommend vaccination over either no vaccination or performing SARS-CoV-2 vaccine/excipient screening allergy testing for individuals without history of a severe allergic reaction to the SARS-CoV-2 vaccine/excipient, and a shared decision-making paradigm in consultation with an allergy specialist for individuals with a history of a severe allergic reaction to the SARS-CoV-2 vaccine/excipient. We recommend further research to clarify SARS-CoV-2 vaccine/vaccine excipient testing utility in individuals potentially allergic to SARS-CoV2 vaccines or their excipients.

Maternal Vaccination and Infant Influenza and Pertussis

BACKGROUND AND OBJECTIVES

Infant influenza and pertussis disease causes considerable morbidity and mortality worldwide. We examined the effectiveness of maternal influenza and pertussis vaccines in preventing these diseases in infants.

METHODS

This inception cohort study comprised women whose pregnancies ended between September 1, 2015, and December 31, 2017, in Victoria, Australia. Maternal vaccination status was sourced from the Victorian Perinatal Data Collection and linked to 5 data sets to ascertain infant outcomes and vaccination. The primary outcome of interest was laboratory-confirmed influenza or pertussis disease in infants aged <2 months, 2 to <6 months, and <6 months combined. Secondary outcomes included infant hospitalization (emergency presentation or admission) and death. Risk ratios and 95% confidence intervals (CIs) were estimated by Poisson regression. Vaccine effectiveness (VE) was estimated as (1 minus the risk ratio) x 100%.

RESULTS

Among 186 962 pregnant women, 85 830 (45.9%) and 128 060 (68.5%) were vaccinated against influenza and pertussis, respectively. There were 175 and 51 infants with laboratory-confirmed influenza and pertussis disease, respectively. Influenza VE was 56.1% (95% CI, 23.3% to 74.9%) for infants aged <2 months and 35.7% (2.2% to 57.7%) for infants aged 2 to <6 months. Pertussis VE was 80.1% (95% CI, 37.1% to 93.7%) for infants aged <2 months and 31.8% (95% CI, -39.1% to 66.6%) for infants aged 2 to <6 months.

CONCLUSIONS

Our study provides evidence of the direct effectiveness of maternal influenza and pertussis vaccination in preventing these diseases in infants aged <2 months. The findings strengthen the importance of maternal vaccination to prevent these diseases in infants.

Cost-Effectiveness of Food Allergy Interventions in Children: A Systematic Review of Economic Evaluations

OBJECTIVES

To identify published economic evaluations of interventions aimed at preventing, diagnosing, or treating food allergies in children.

METHODS

We examined economic evaluations published from 2000 to 2019. Data analyzed included: food allergy type, study population/setting, intervention/comparator, and economic evaluation details. Quality assessment used reporting and economic modeling checklists. Two reviewers simultaneously undertook article screening, data extraction, and quality assessment.

RESULTS

17 studies were included: 8 peanut allergy (PA) studies, 8 cow's milk allergy (CMA) studies, and 1 egg allergy (EA) study. All PA studies reported incremental costs per quality-adjusted life-year gained for diagnostic strategies, management pathways for peanut exposure, and immunotherapies. Immunotherapies rendered inconsistent cost-effectiveness results. CMA studies reported costs per symptom-free day or probability of developing CMA tolerance. Cost-effectiveness of extensively hydrolyzed casein formula for CMA treatment was consistently demonstrated. Early introduction of cooked egg in first year of life dominated all EA prevention strategies. Quality assessment showed average noncompliance for 3.5 items/study (range 0-11) for modeling methods and 3.4 items/study (range 0-8) for reporting quality. Key quality concerns included limited justification for model choice, evidence base for model parameters, source of utility values, and representation of uncertainty.

CONCLUSION

Recent cost-effectiveness literature of interventions in PA, CMA, and EA is limited and diverse. Interventions for diagnosis and treatment of CMA and prevention of EA were generally cost-effective; however, results for PA were variable and dependent on effectiveness and utility values used. There is a need to expand economic evaluation of interventions for childhood food allergy and to improve methods and reporting.

Epigenetic programming underpins B-cell dysfunction in peanut and multi-food allergy

OBJECTIVE

Rates of IgE-mediated food allergy (FA) have increased over the last few decades, and mounting evidence implicates disruption of epigenetic profiles in various immune cell types in FA development. Recent data implicate B-cell dysfunction in FA; however, few studies have examined epigenetic changes within these cells.

METHODS

We assessed epigenetic and transcriptomic profiles in purified B cells from adolescents with FA, comparing single-food-allergic (peanut only), multi-food-allergic (peanut and ≥1 other food) and non-allergic (control) individuals. Adolescents represent a phenotype of persistent and severe FA indicative of a common immune deviation.

RESULTS

We identified 144 differentially methylated probes (DMPs) and 116 differentially expressed genes (DEGs) that distinguish B cells of individuals with FA from controls, including differential methylation of the PM20D1 promoter previously associated with allergic disorders. Subgroup comparisons found 729 DMPs specific to either single-food- or multi-food-allergic individuals, suggesting epigenetic distinctions between allergy groups. This included two regions with increased methylation near three S100 genes in multi-food-allergic individuals. Ontology results of DEGs specific to multi-food-allergic individuals revealed enrichment of terms associated with myeloid cell activation. Motif enrichment analysis of promoters associated with DMPs and DEGs showed differential enrichment for motifs recognised by transcription factors regulating B- and T-cell development, B-cell lineage determination and TGF-β signalling pathway between the multi-food-allergic and single-food-allergic groups.

CONCLUSION

Our data highlight epigenetic changes in B cells associated with peanut allergy, distinguishing features of the epigenome between single-food- and multi-food-allergic individuals and revealing differential developmental pathways potentially underpinning these distinct phenotypes.

National predictors of influenza vaccine uptake in pregnancy: the FluMum prospective cohort study, Australia, 2012-2015

OBJECTIVE

Ascertain predictors of inactivated influenza vaccine (IIV) uptake in pregnancy in mother-infant pairs from six Australian sites over four consecutive influenza seasons (2012-2015).

METHODS

Prospective observational cohort study calculating proportions of unvaccinated and vaccinated pregnancies. Multivariable logistic regression calculating adjusted odds ratios (aOR) and 95% confidence intervals (95%CI) to determine demographic, pregnancy and birth characteristics as predictors of IIV uptake in pregnancy.

RESULTS

Uptake of IIV was 36% (n=3,651/9,878) with only 3-4% during the first trimester. Validation of IIV receipt was obtained for 77% of vaccinated participants. Predictors of IIV uptake in pregnancy were: healthcare provider recommendation to have IIV during pregnancy (aOR 7.04 [95%CI 5.83-8.50]): GP (aOR 4.12 [95%CI 3.43-4.98]), obstetrician (aOR 4.41 [95%CI 3.45-5.64]), midwife (aOR 1.88 [95%CI 1.51-2.36]); previous IIV within 12 months of their current pregnancy (aOR 2.87 [95%CI 2.36-3.50]); and pertussis vaccination during the current pregnancy (aOR 4.88 [95%CI 4.08-5.83]). Conclusions and implications for public health: Healthcare provider discussions with pregnant women about the risks associated with influenza infection during pregnancy and early infancy and evidence about the safety and effectiveness of IIV are required. Recommending and offering IIV in pregnancy needs to be included in these discussions to improve uptake.

Correlation of Vaccine Responses

Introduction

The humoral response to vaccinations varies widely between individuals. There is no data available on the correlation between responses to different vaccines. In this study, we investigated the correlation of antibody responses between routine vaccine antigens in infants.

Methods

One and seven months after the 6-month vaccinations and one month after the 12-month vaccinations, antibody concentrations to diphtheria, tetanus, pertussis, polio (serotypes 1-3), Haemophilus influenzae type b (Hib), pneumococcus (13 serotypes), meningococcus C, measles, mumps and rubella were measured using fluorescent bead-based multiplex immune-assays. For the correlation of antibody responses, Spearman's rank correlation coefficients (ρ) with 95% confidence intervals (CI) were calculated between responses to each vaccine antigen.

Results

The correlation between concentrations of antibodies to the vaccinations ending at 6 months of age was higher one month compared to seven months after vaccination. The strongest correlations at both time points were observed between antibody responses to different polio serotypes, certain pneumococcal serotypes and between responses to diphtheria and pneumococcal (conjugated to a diphtheria toxoid) vaccine antigens. Correlation between responses to tetanus, Hib, pertussis, polio and other vaccine antigens were weak. The correlation between antibody responses to the 12-month vaccine antigens was weaker than to the 6-month vaccine antigens and there was a negative correlation between responses to measles, mumps, rubella vaccine and non-live vaccine antigens (meningococcus C, tetanus and Hib). There was only weak correlation between antibody responses to vaccines of the same type (e.g. conjugated polysaccharide or toxoid vaccines).

Conclusion

Correlation between antibody responses to similar antigens in the same vaccine (such as different serotypes of a bacteria or virus), as well as responses to antigens conjugated to similar carrier proteins, are strong. In contrast, correlation between responses to other vaccines are weak. Measuring antibody responses to one or a few vaccine antigens therefore does not offer a reliable surrogate marker of responses to unrelated vaccines.

Altered immune cell profiles and impaired CD4 T-cell activation in single and multi-food allergic adolescents

BACKGROUND

Approximately 5% of adolescents have a food allergy, with peanut and tree nut allergies the most common. Having two or more food allergies in adolescence also doubles the risk of any adverse food reaction, and is associated with increased dietary and social burden. Investigations of immune function in persistently food allergic children are rare.

OBJECTIVE

In the present study, we aimed to investigate the immune mechanisms that underlie food allergy in adolescence.

METHODS

We used high-dimensional flow cytometry, unsupervised computational analysis and functional studies to comprehensively phenotype a range of non-antigen-specific immune parameters in a group of well-characterized adolescents with clinically defined single peanut allergy, multi-food allergy and aged-matched non-food allergic controls.

RESULTS

We show that food allergic adolescents have higher circulating proportions of dendritic cells (p = .0084, FDR-adjusted p = .087, median in no FA: 0.63% live cells, in FA: 0.93%), and higher frequency of activated, memory-like Tregs relative to non-food allergic adolescents (p = .011, FDR-adjusted p = .087, median in no FA: 0.49% live cells, in FA: 0.65%). Cytokine profiling revealed that CD3/CD28 stimulated naïve CD4 T cells from food allergic adolescents produced less IL-6 (p = .0020, FDR-adjusted p = .018, median log2 fold change [stimulated/unstimulated] in no FA: 3.03, in FA: 1.92) and TNFα (p = .0044, FDR-adjusted p = .020, median in no FA: 9.16, in FA: 8.64) and may secrete less IFNγ (p = .035, FDR-adjusted p = .11, median in no FA: 6.29, in FA: 5.67) than naïve CD4 T cells from non-food allergic controls. No differences between clinical groups were observed for LPS-stimulated monocyte secretion of cytokines.

CONCLUSIONS

These results have important implications for understanding the evolution of the immune response in food allergy throughout childhood, revealing that dendritic cell and T-cell signatures previously identified in early life may persist through to adolescence.

OPTIMUM study protocol: an adaptive randomised controlled trial of a mixed whole-cell/acellular pertussis vaccine schedule

INTRODUCTION

Combination vaccines containing whole-cell pertussis antigens were phased out from the Australian national immunisation programme between 1997 and 1999 and replaced by the less reactogenic acellular pertussis (aP) antigens. In a large case-control study of Australian children born during the transition period, those with allergist diagnosed IgE-mediated food allergy were less likely to have received whole-cell vaccine in early infancy than matched population controls (OR: 0.77 (95% CI, 0.62 to 0.95)). We hypothesise that a single dose of whole-cell vaccine in early infancy is protective against IgE-mediated food allergy.

METHODS AND ANALYSIS

This adaptive double-blind randomised controlled trial is investigating whether a mixed whole-cell/aP vaccine schedule prevents allergic disease in the first year of life. The primary outcome is IgE-mediated food allergy by 12 months of age. Secondary outcomes include new onset of atopic dermatitis by 6 or 12 months of age; sensitisation to at least one allergen by 12 months of age; seroconversion in anti-pertussis toxin IgG titres after vaccination with aP booster at 18 months of age; and solicited systemic and local adverse events following immunisation with pertussis-containing vaccines. Analyses will be performed using a Bayesian group sequential design.

ETHICS AND DISSEMINATION

This study has been approved by the Child and Adolescent Health Service Human Research Ethics Committee, Perth, Western Australia (RGS 00019). The investigators will ensure that this trial is conducted in accordance with the principles of the Declaration of Helsinki and with the International Conference on Harmonisation Guidelines for Good Clinical Practice. Individual consent will be requested. Parents will be reimbursed reasonable travel and parking costs to attend the study visits. The dissemination of these research findings will follow the National Health and Medical Research Council of Australia Open Access Policy.

TRIAL REGISTRATION NUMBER

ACTRN12617000065392p.

Immunisation and allergy in children and adults: A case-based approach

BACKGROUND

Adverse events following immunisation (AEFIs) are often attributed to vaccine hypersensitivity. However, many of these possible allergic reactions are unlikely to be confirmed as true vaccine allergies but rather coincidental symptoms that may mimic an allergic reaction.

OBJECTIVE

By using case studies, the authors show the variation of presentations of potential hypersensitivity AEFIs. Case studies are used to illustrate a general approach to investigation and management of these reactions.

DISCUSSION

AEFIs are commonly seen in general practice, and it can often be difficult to differentiate between the underlying mechanisms. It is important to be able to identify a potential hypersensitivity reaction so that it can be reported to the appropriate local pharmacovigilance system and patients can be reviewed by immunisation specialists to evaluate, investigate and manage future immunisations where required.