Prevalence of egg sensitization in Turkish infants based on skin prick test

Prevalence estimates of eight big food allergies in Europe: Updated systematic review and meta-analysis

In 2014, the European Academy of Allergy and Clinical Immunology published prevalence estimates for food allergy (FA) and food sensitization (FS) to the so-called eight big food allergens (i.e. cow's milk, egg, wheat, soy, peanut, tree nuts, fish and shellfish) in Europe for studies published between 2000 and 2012. The current work provides 10-year updated prevalence estimates for these food allergens. A protocol was registered on PROSPERO before starting the research (reference number CRD42021266657). Six databases were searched for studies published 2012-2021, added to studies published up to 2012, resulting in a total of 93 studies. Most studies were graded as at moderate risk of bias. The overall pooled estimates for all age groups of self-reported lifetime prevalence were as follows: cow's milk (5.7%, 95% confidence interval 4.4-6.9), egg (2.4%, 1.8-3.0), wheat (1.6%, 0.9-2.3), soy (0.5%, 0.3-0.7), peanut (1.5%, 1.0-2.1), tree nuts (0.9%, 0.6-1.2), fish (1.4%, 0.8-2.0) and shellfish (0.4%, 0.3-0.6). The point prevalence of food challenge-verified allergy were as follows: cow's milk (0.3%, 0.1-0.5), egg (0.8%, 0.5-1.2), wheat (0.1%, 0.01-0.2), soy (0.3%, 0.1-0.4), peanut (0.1%, 0.0-0.2), tree nuts (0.04%, 0.02-0.1), fish (0.02%, 0.0-0.1) and shellfish (0.1%, 0.0-0.2). With some exceptions, the prevalence of allergy to common foods did not substantially change during the last decade; variations by European regions were observed.

Frequency of food allergy in Europe: An updated systematic review and meta-analysis

Food allergy (FA) is increasingly reported in Europe, however, the latest prevalence estimates were based on studies published a decade ago. The present work provides the most updated estimates of the prevalence and trends of FA in Europe. Databases were searched for studies published between 2012 and 2021, added to studies published up to 2012. In total, 110 studies were included in this update. Most studies were graded as moderate risk of bias. Pooled lifetime and point prevalence of self-reported FA were 19.9% (95% CI 16.6-23.3) and 13.1% (95% CI 11.3-14.8), respectively. The point prevalence of sensitization based on specific IgE (slgE) was 16.6% (95% CI 12.3-20.8), skin prick test (SPT) 5.7% (95% CI 3.9-7.4), and positive food challenge 0.8% (95% CI 0.5-0.9). While lifetime prevalence of self-reported FA and food challenge positivity only slightly changed, the point prevalence of self-reported FA, sIgE and SPT positivity increased from previous estimates. This may reflect a real increase, increased awareness, increased number of foods assessed, or increased number of studies from countries with less data in the first review. Future studies require rigorous designs and implementation of standardized methodology in diagnosing FA, including use of double-blinded placebo-controlled food challenge to minimize potential biases.

Appropriate age range for introduction of complementary feeding into an infant's diet

Following a request from the European Commission, the Panel on Nutrition, Novel Foods and Food Allergens (NDA) revised its 2009 Opinion on the appropriate age for introduction of complementary feeding of infants. This age has been evaluated considering the effects on health outcomes, nutritional aspects and infant development, and depends on the individual's characteristics and development. As long as foods have an age-appropriate texture, are nutritionally appropriate and prepared following good hygiene practices, there is no convincing evidence that at any age investigated in the included studies (< 1 to < 6 months), the introduction of complementary foods (CFs) is associated with adverse health effects or benefits (except for infants at risk of iron depletion). For nutritional reasons, the majority of infants need CFs from around 6 months of age. Infants at risk of iron depletion (exclusively breastfed infants born to mothers with low iron status, or with early umbilical cord clamping (< 1 min after birth), or born preterm, or born small-for-gestational age or with high growth velocity) may benefit from earlier introduction of CFs that are a source of iron. The earliest developmental skills relevant for consuming pureed CFs can be observed between 3 and 4 months of age. Skills for consuming finger foods can be observed in some infants at 4 months, but more commonly at 5-7 months. The fact that an infant may be ready from a neurodevelopmental perspective to progress to a more diversified diet before 6 months of age does not imply that there is a need to introduce CFs. There is no reason to postpone the introduction of potentially allergenic foods (egg, cereals, fish and peanut) to a later age than that of other CFs as far as the risk of developing atopic diseases is concerned. Regarding the risk of coeliac disease, gluten can be introduced with other CFs.

Prevalence of common food allergies in Europe: a systematic review and meta-analysis

Allergy to cow's milk, egg, wheat, soy, peanut, tree nuts, fish, and shellfish constitutes the majority of food allergy reactions, but reliable estimates of their prevalence are lacking. This systematic review aimed to provide up-to-date estimates of their prevalence in Europe.Studies published in Europe from January 1, 2000, to September 30, 2012, were identified from searches of four electronic databases. Two independent reviewers appraised the studies and extracted the estimates of interest. Data were pooled using random-effects meta-analyses. Fifty studies were included in a narrative synthesis and 42 studies in the meta-analyses. Although there were significant heterogeneity between the studies, the overall pooled estimates for all age groups of self-reported lifetime prevalence of allergy to cow's milk, egg, wheat, soy, peanut, tree nuts, fish, and shellfish were 6.0% (95% confidence interval: 5.7-6.4), 2.5% (2.3-2.7), 3.6% (3.0-4.2), 0.4% (0.3-0.6), 1.3% (1.2-1.5), 2.2% (1.8-2.5), and 1.3% (0.9-1.7), respectively. The prevalence of food-challenge-defined allergy to cow's milk, egg, wheat, soy, peanut, tree nuts, fish, and shellfish was 0.6% (0.5-0.8), 0.2% (0.2-0.3), 0.1% (0.01-0.2), 0.3% (0.1-0.4), 0.2% (0.2-0.3), 0.5% (0.08-0.8), 0.1% (0.02-0.2), and 0.1% (0.06-0.3), respectively. Allergy to cow's milk and egg was more common among younger children, while allergy to peanut, tree nuts, fish, and shellfish was more common among the older ones. There were insufficient data to compare the estimates of soy and wheat allergy between the age groups. Allergy to most foods, except soy and peanut, appeared to be more common in Northern Europe. In summary, the lifetime self-reported prevalence of allergy to common foods in Europe ranged from 0.1 to 6.0%. The heterogeneity between studies was high, and participation rates varied across studies reaching as low as <20% in some studies. Standardizing the methods of assessment of food allergies and initiating strategies to increase participation will advance this evidence base.

Optimal timing for solids introduction - why are the guidelines always changing?

There have been dramatic changes in timing of first exposure to solid foods for children over the last 40 years, ranging from exposure prior to 4 months of age for most infants in the 1960s, to guidelines recommending delaying solids until after 6 months of age introduced in the 1990s. Infant diet, specifically age of weaning and age at introduction of allergenic foods, has long been thought to play a role food allergy. However, controversy surrounding the relationship between timing of introduction of foods and development of food allergy has lead to a plethora of inconsistent infant feeding guidelines both between and within countries. The aims of this article were to discuss the history of changing guidelines for optimal timing of introduction of solids in general and allergenic solids in particular and the evidence (or lack thereof) underpinning recommendations at each of these time-points. We present the current clinical equipoise with regards to recently revised guidelines published almost simultaneously in the UK, US and Australia and argue that guideline modification about timing of introduction (both for high risk infants but also for the general population) will require careful review of emerging literature to provide a true evidence base to inform public health practice such as infant feeding guidelines.

The epidemiology of food allergy in Europe: a systematic review and meta-analysis

Food allergy (FA) is an important atopic disease although its precise burden is unclear. This systematic review aimed to provide recent, up-to-date data on the incidence, prevalence, time trends, and risk and prognostic factors for FA in Europe. We searched four electronic databases, covering studies published from 1 January 2000 to 30 September 2012. Two independent reviewers appraised the studies and qualified the risk of bias using the Critical Appraisal Skills Programme tool. Seventy-five eligible articles (comprising 56 primary studies) were included in a narrative synthesis, and 30 studies in a random-effects meta-analysis. Most of the studies were graded as at moderate risk of bias. The pooled lifetime and point prevalence of self-reported FA were 17.3% (95% CI: 17.0-17.6) and 5.9% (95% CI: 5.7-6.1), respectively. The point prevalence of sensitization to ≥1 food as assessed by specific IgE was 10.1% (95% CI: 9.4-10.8) and skin prick test 2.7% (95% CI: 2.4-3.0), food challenge positivity 0.9% (95% CI: 0.8-1.1). While the incidence of FA appeared stable over time, there was some evidence that the prevalence may be increasing. There were no consistent risk or prognostic factors for the development or resolution of FA identified, but sex, age, country of residence, familial atopic history, and the presence of other allergic diseases seem to be important. Food allergy is a significant clinical problem in Europe. The evidence base in this area would benefit from additional studies using standardized, rigorous methodology; data are particularly required from Eastern and Southern Europe.

Early life precursors, epigenetics, and the development of food allergy

Food allergy (FA), a major clinical and public health concern worldwide, is caused by a complex interplay of environmental exposures, genetic variants, gene-environment interactions, and epigenetic alterations. This review summarizes recent advances surrounding these key factors, with a particular focus on the potential role of epigenetics in the development of FA. Epidemiologic studies have reported a number of nongenetic factors that may influence the risk of FA, such as timing of food introduction and feeding pattern, diet/nutrition, exposure to environmental tobacco smoking, prematurity and low birth weight, microbial exposure, and race/ethnicity. Current studies on the genetics of FA are mainly conducted using candidate gene approaches, which have linked more than 10 genes to the genetic susceptibility of FA. Studies on gene-environment interactions of FA are very limited. Epigenetic alteration has been proposed as one of the mechanisms to mediate the influence of early life environmental exposures and gene-environment interactions on the development of diseases later in life. The role of epigenetics in the regulation of the immune system and the epigenetic effects of some FA-associated environmental exposures are discussed in this review. There is a particular lack of large-scale prospective birth cohort studies that simultaneously assess the interrelationships of early life exposures, genetic susceptibility, epigenomic alterations, and the development of FA. The identification of these key factors and their independent and joint contributions to FA will allow us to gain important insight into the biological mechanisms by which environmental exposures and genetic susceptibility affect the risk of FA and will provide essential information to develop more effective new paradigms in the diagnosis, prevention, and management of FA.

Randomized clinical trial of immunogenicity and safety of a recombinant H1N1/2009 pandemic influenza vaccine containing Advax™ polysaccharide adjuvant

BACKGROUND

Timely vaccine supply is critical during influenza pandemics. A recombinant hemagglutinin (rHA)-based vaccine could overcome production hurdles of egg-based vaccines but has never previously been tested in a real-life pandemic setting. The primary aim was to determine the efficacy of a recombinant pandemic vaccine and whether its immunogenicity could be enhanced by a novel polysaccharide adjuvant (Advax™).

METHODS

281 adults aged 18-70 years were recruited in a randomized, subject and observer blinded, parallel-group study of rHA H1N1/2009 vaccine with or without adjuvant. Immunizations were at 0 and 3 weeks with rHA 3, 11 or 45 μg. Serology and safety was followed for 6 months.

RESULTS

At baseline, only 9.1% of subjects (95% CI: 6.0-13.2) had seroprotective H1N1/2009 titers. Seroconversion rates varied by rHA dose, presence of adjuvant, subject age and number of immunizations. Eighty percent (95% CI: 52-96) of 18-49 year olds who received rHA 45 μg with adjuvant were seroprotected at week 3, representing a 11.1-fold increase in antibody titers from baseline. Advax™ adjuvant increased seroprotection rates by 1.9 times after the first, and 2.5 times after the second, immunization when compared to rHA alone. Seroprotection was sustained at 26 weeks and the vaccine was well tolerated with no safety issues.

CONCLUSIONS

The study confirmed the ability to design, manufacture, and release a recombinant vaccine within a short time from the start of an actual influenza pandemic. Advax™ adjuvant significantly enhanced rHA immunogenicity.