European all-cause excess and influenza-attributable mortality in the 2017/18 season: should the burden of influenza B be reconsidered?

OBJECTIVES: Weekly monitoring of European all-cause excess mortality, the EuroMOMO network, observed high excess mortality during the influenza B/Yamagata dominated 2017/18 winter season, especially among elderly. We describe all-cause excess and influenza-attributable mortality during the season 2017/18 in Europe. METHODS: Based on weekly reporting of mortality from 24 European countries or sub-national regions, representing 60% of the European population excluding the Russian and Turkish parts of Europe, we estimated age stratified all-cause excess morality using the EuroMOMO model. In addition, age stratified all-cause influenza-attributable mortality was estimated using the FluMOMO algorithm, incorporating influenza activity based on clinical and virological surveillance data, and adjusting for extreme temperatures. RESULTS: Excess mortality was mainly attributable to influenza activity from December 2017 to April 2018, but also due to exceptionally low temperatures in February-March 2018. The pattern and extent of mortality excess was similar to the previous A(H3N2) dominated seasons, 2014/15 and 2016/17. The 2017/18 overall all-cause influenza-attributable mortality was estimated to be 25.4 (95%CI 25.0-25.8) per 100,000 population; 118.2 (116.4-119.9) for persons aged 65. Extending to the European population this translates into over-all 152,000 deaths. CONCLUSIONS: The high mortality among elderly was unexpected in an influenza B dominated season, which commonly are considered to cause mild illness, mainly among children. Even though A(H3N2) also circulated in the 2017/18 season and may have contributed to the excess mortality among the elderly, the common perception of influenza B only having a modest impact on excess mortality in the older population may need to be reconsidered.

A new framework for the documentation and interpretation of oral food challenges in population-based and clinical research.

BACKGROUND: The conduct of oral food challenges as the preferred diagnostic standard for food allergy (FA) was harmonized over the last years. However, documentation and interpretation of challenge results, particularly in research settings, are not sufficiently standardized to allow valid comparisons between studies. Our aim was to develop a diagnostic toolbox to capture and report clinical observations in double-blind placebo-controlled food challenges (DBPCFC). METHODS: A group of experienced allergists, paediatricians, dieticians, epidemiologists and data managers developed generic case report forms and standard operating procedures for DBPCFCs and piloted them in three clinical centres. The follow-up of the EuroPrevall/iFAAM birth cohort and other iFAAM work packages applied these methods. RECOMMENDATIONS: A set of newly developed questionnaire or interview items capture the history of FA. Together with sensitization status, this forms the basis for the decision to perform a DBPCFC, following a standardized decision algorithm. A generic form including details about severity and timing captures signs and symptoms observed during or after the procedures. In contrast to the commonly used dichotomous outcome FA vs no FA, the allergy status is interpreted in multiple categories to reflect the complexity of clinical decision-making. CONCLUSION: The proposed toolbox sets a standard for improved documentation and harmonized interpretation of DBPCFCs. By a detailed documentation and common terminology for communicating outcomes, these tools hope to reduce the influence of subjective judgment of supervising physicians. All forms are publicly available for further evolution and free use in clinical and research settings.

Can we identify patients at risk of life-threatening allergic reactions to food?

Anaphylaxis has been defined as a 'severe, life-threatening generalized or systemic hypersensitivity reaction'. However, data indicate that the vast majority of food-triggered anaphylactic reactions are not life-threatening. Nonetheless, severe life-threatening reactions do occur and are unpredictable. We discuss the concepts surrounding perceptions of severe, life-threatening allergic reactions to food by different stakeholders, with particular reference to the inclusion of clinical severity as a factor in allergy and allergen risk management. We review the evidence regarding factors that might be used to identify those at most risk of severe allergic reactions to food, and the consequences of misinformation in this regard. For example, a significant proportion of food-allergic children also have asthma, yet almost none will experience a fatal food-allergic reaction; asthma is not, in itself, a strong predictor for fatal anaphylaxis. The relationship between dose of allergen exposure and symptom severity is unclear. While dose appears to be a risk factor in at least a subgroup of patients, studies report that individuals with prior anaphylaxis do not have a lower eliciting dose than those reporting previous mild reactions. It is therefore important to consider severity and sensitivity as separate factors, as a highly sensitive individual will not necessarily experience severe symptoms during an allergic reaction. We identify the knowledge gaps that need to be addressed to improve our ability to better identify those most at risk of severe food-induced allergic reactions.

Incidence and natural history of hen's egg allergy in the first 2 years of life-the EuroPrevall birth cohort study.

BACKGROUND: Parents and health staff perceive hen's egg allergy (HEA) as a common food allergy in early childhood, but the true incidence is unclear because population-based studies with gold-standard diagnostic criteria are lacking. OBJECTIVE: To establish the incidence and course of challenge-confirmed HEA in children, from birth until the age of 24 months, in different European regions. METHODS: In the EuroPrevall birth cohort study, children with a suspected HEA and their age-matched controls were evaluated in 9 countries, using a standardized protocol including measurement of HE-specific immunoglobulin E-antibodies in serum, skin prick tests, and double-blind, placebo-controlled food challenges (DBPCFC). RESULTS: Across Europe, 12 049 newborns were enrolled, and 9336 (77.5%) were followed up to 2 years of age. In 298 children, HEA was suspected and DBPCFC was offered. HEA by age two was confirmed in 86 of 172 challenged children (mean raw incidence 0.84%, 95% confidence interval (95% CI) 0.67-1.03). Adjusted mean incidence of HEA was 1.23% (95% CI 0.98-1.51) considering possible cases among eligible children who were not challenged. Centre-specific incidence ranged from United Kingdom (2.18%, 95% CI 1.27-3.47) to Greece (0.07%). Half of the HE-allergic children became tolerant to HE within 1 year after the initial diagnosis. CONCLUSIONS: The largest multinational European birth cohort study on food allergy with gold-standard diagnostic methods showed that the mean adjusted incidence of HEA was considerably lower than previously documented, although differences in incidence rates among countries were noted. Half of the children with documented HEA gained tolerance within 1 year postdiagnosis.

Incidence and natural history of challenge-proven cow's milk allergy in European children--EuroPrevall birth cohort.

BACKGROUND: Cow's milk allergy (CMA) is one of the most commonly reported childhood food problems. Community-based incidence and prevalence estimates vary widely, due to possible misinterpretations of presumed reactions to milk and differences in study design, particularly diagnostic criteria. METHODS: Children from the EuroPrevall birth cohort in 9 European countries with symptoms possibly related to CMA were invited for clinical evaluation including cows' milk-specific IgE antibodies (IgE), skin prick test (SPT) reactivity and double-blind, placebo-controlled food challenge. RESULTS: Across Europe, 12 049 children were enrolled, and 9336 (77.5%) were followed up to 2 years of age. CMA was suspected in 358 children and confirmed in 55 resulting in an overall incidence of challenge-proven CMA of 0.54% (95% CI 0.41-0.70). National incidences ranged from 1% (in the Netherlands and UK) to <0.3% (in Lithuania, Germany and Greece). Of all children with CMA, 23.6% had no cow's milk-specific IgE in serum, especially those from UK, the Netherlands, Poland and Italy. Of children with CMA who were re-evaluated one year after diagnosis, 69% (22/32) tolerated cow's milk, including all children with non-IgE-associated CMA and 57% of those children with IgE-associated CMA. CONCLUSIONS: This unique pan-European birth cohort study using the gold standard diagnostic procedure for food allergies confirmed challenge-proven CMA in <1% of children up to age 2. Affected infants without detectable specific antibodies to cow's milk were very likely to tolerate cow's milk one year after diagnosis, whereas only half of those with specific antibodies in serum 'outgrew' their disease so soon.

Predictive values of component-specific IgE for the outcome of peanut and hazelnut food challenges in children.

BACKGROUND: Oral challenges are the gold standard in food allergy diagnostic, but time-consuming. Aim of the study was to investigate the role of peanut- and hazelnut-component-specific IgE in the diagnostics of peanut and hazelnut allergy and to identify cutoff levels to make some challenges superfluous. METHODS: In a prospective and multicenter study, children with suspected peanut or hazelnut allergy underwent oral challenges. Specific IgE to peanut, hazelnut, and their components (Ara h 1, Ara h 2, Ara h 3, and Ara h 8, Cor a 1, Cor a 8, Cor a 9, and Cor a 14) were determined by ImmunoCAP-FEIA. RESULTS: A total of 210 children were challenged orally with peanut and 143 with hazelnut. 43% of the patients had a positive peanut and 31% a positive hazelnut challenge. With an area under the curve of 0.92 and 0.89, respectively, Ara h 2 and Cor a 14-specific IgE discriminated between allergic and tolerant children better than peanut- or hazelnut-specific IgE. For the first time, probability curves for peanut and hazelnut components have been calculated. A 90% probability for a positive peanut or hazelnut challenge was estimated for Ara h 2-specific IgE at 14.4 kU/l and for Cor a 14-specific IgE at 47.8 kU/l. A 95% probability could only be estimated for Ara h 2 at 42.2 kU/l. CONCLUSIONS: Ara h 2- and Cor a 14-specific IgE are useful to estimate the probability for a positive challenge outcome in the diagnostic work-up of peanut or hazelnut allergy making some food challenges superfluous.

First European data from the network of severe allergic reactions (NORA).

BACKGROUND: Occurrence, elicitors and treatment of severe allergic reactions are recognized and reported differently between countries. We aimed to collect standardized data throughout Europe on anaphylaxis referred for diagnosis and counselling. METHODS: Tertiary allergy, dermatology and paediatric units in 10 European countries took part in this pilot phase of the first European Anaphylaxis Registry, from June 2011 to March 2014. An online questionnaire was used to collect data on severe allergic reactions based on the medical history and diagnostics. RESULTS: Fifty-nine centres reported 3333 cases of anaphylaxis, with 26.7% below 18 years of age. Allergic reactions were mainly caused by food (children and adults 64.9% and 20.2%, respectively) and insect venom (20.2% and 48.2%) and less often by drugs (4.8% and 22.4%). Most reactions occurred within 30 min of exposure (80.5%); a delay of 4+ hours was mainly seen in drug anaphylaxis (6.7%). Symptom patterns differed by elicitor, with the skin being affected most often (84.1%). A previous, usually milder reaction to the same allergen was reported by 34.2%. The mainstay of first-line treatment by professionals included corticoids (60.4%) and antihistamines (52.8%). Only 13.7% of lay- or self-treated reactions to food and 27.6% of insect anaphylaxis received on-site adrenaline. CONCLUSION: This pilot phase of a pan-European registry for severe allergic reactions provides for the first time data on anaphylaxis throughout Europe, demonstrates its potential functionality and allows a comparison of symptom patterns, elicitors and treatment habits between referral centres and countries.

Individual cow's milk allergens as prognostic markers for tolerance development?

BACKGROUND: Cow's milk allergy (CMA) is one of the most common causes of food allergy in the first years of life. Fortunately, the majority of children with CMA develop clinical tolerance with time. However, no good individual markers exist to predict whether this will occur. Therefore, a prognosis to identify children with persistent CMA at diagnosis would be helpful. OBJECTIVE: In this study, we sought to assess whether measurement of IgE to individual allergens of cow's milk (CM) would separate patients with persistent CMA from those who became clinically tolerant to CM over time. METHODS: A total of 52 patients ranging from 3 months to 114 months of age with proven CMA by DBPCFC were followed over time. From these 52 patients, 32 (61.5%) patients became tolerant in the analysed time period. All patients were rechallenged at least once, some were rechallenged two or three times. Serum was analysed prior to each challenge for specific IgE, IgG and IgG4 binding to crude CM protein as well as to individual allergens of CM. RESULTS: The individual likelihood of outgrowing CMA significantly correlates with a low level of CM-specific IgE as well as a low level of specific IgE to α-lactalbumin, ß-lactoglobulin (Bos d5.0102), κ-casein and α(s1) -casein. No significant correlation was found for IgE levels to total casein, lactoferrin, ß-casein and ß-lactoglobulin (Bos d5.0101) as well as IgG and IgG4 levels to α-lactalbumin, ß-lactoglobulin and total casein. CONCLUSIONS: CM-specific IgE is a good prognostic marker for persistence of CMA. In addition, component-resolved diagnostic showed similar results. However, in our view, the rising laboratory costs do not justify a measurement on a daily basis. Additional determination of specific IgG or IgG4 levels was not useful in predicting tolerance development in our study population.

Anaphylaxis in an emergency setting - elicitors, therapy and incidence of severe allergic reactions.

BACKGROUND: Anaphylaxis is a severe potentially life-threatening hypersensitivity reaction with an estimated lifetime prevalence of 0.5-2.0%. The prevalence and incidence of anaphylactic reactions in Germany are unknown. We therefore assessed anaphylactic patients seen by emergency physicians in the Berlin area covering 4 million people. METHODS: A standardised questionnaire was filled from 2008 to 2010 by the emergency physicians. RESULTS: A total of 333 cases of anaphylaxis were reported. 295 of these met the inclusion criteria for severity and were analysed. 13.9% (n = 41) were reactions with respiratory symptoms, 25.4% (n = 75) with cardiovascular, and in 60.7% (n = 179) of cases, respiratory and cardiovascular symptoms were reported. Two reactions were fatal. The most common elicitors were food products (32.2%), drugs (29.2%) and insect venom (19.3%). The most frequently given drugs were corticoids and antihistamines, but not adrenaline. For 2008, the calculated incidence was 4.5 per 100 000. CONCLUSIONS: Our data show that food products are frequent elicitors of severe allergic reactions in the general population including children and adults. It unravels a strong underuse of adrenaline by emergency physicians, not reflecting treatment protocols according to the current guidelines. As data obtained from allergists reveal a different rank order of elicitors, this study suggests that food-allergic adult patients may present a risk population and should receive more attention by allergists.

Outcome of oral food challenges in children in relation to symptom-eliciting allergen dose and allergen-specific IgE.

BACKGROUND: Oral food challenge (FC) protocols are discussed with reference to starting doses, dose increments, safety, and predictability of results. The aim of this study was to evaluate the relation of eliciting allergen doses, specific IgE levels and predictive factors to the outcome of FCs in children. METHODS: In 869 children (median age 1.2 years), FCs were performed with cow's milk (n = 633), hen's egg (n = 456), wheat (n = 265) and/or soy (n = 317) starting at 3-5 mg of protein. Each of the seven doses was administered every 30 min using semi-log increases. Severity of symptoms was graded from I to V. IgE was determined prior to challenges. RESULTS: Of the children allergic to egg or milk, 9% and 10%, respectively, experienced reactions already at the first dose. Of these, 14% (egg) and 4% (milk) experienced grade IV reactions. In contrast, few children reacted to the first doses of wheat or soy, and most reactions occurred after the maximum dose. For all allergens, grade V reactions did not occur. However, grade IV reactions were seen at all eliciting doses. Elevated specific IgE level, young age and a history of atopic dermatitis were associated with a positive challenge outcome for milk or egg, and also IgE levels were associated with lower eliciting allergen doses and more severe symptoms. CONCLUSION: Oral FCs bear a risk of severe reactions at all dose levels. Doses of 3-5 mg protein induced symptoms in up to 10% of children allergic to milk or egg. However, food-specific IgE levels are of limited clinical value for the estimation of FC reactions.

The EuroPrevall birth cohort study on food allergy: baseline characteristics of 12,000 newborns and their families from nine European countries.

It is unclear why some children develop food allergy. The EuroPrevall birth cohort was established to examine regional differences in the prevalence and risk factors of food allergy in European children using gold-standard diagnostic criteria. The aim of this report was to describe pre-, post-natal and environmental characteristics among the participating countries. In nine countries across four major European climatic regions, mothers and their newborns were enrolled from October 2005 through February 2010. Using standardized questionnaires, we assessed allergic diseases and self-reported food hypersensitivity of parents and siblings, nutrition during pregnancy, nutritional supplements, medications, mode of delivery, socio-demographic data and home environmental exposures. A total of 12,049 babies and their families were recruited. Self-reported adverse reactions to food ever were considerably more common in mothers from Germany (30%), Iceland, United Kingdom, and the Netherlands (all 20-22%) compared with those from Italy (11%), Lithuania, Greece, Poland, and Spain (all 5-8%). Prevalence estimates of parental asthma, allergic rhinitis and eczema were highest in north-west (Iceland, UK), followed by west (Germany, the Netherlands), south (Greece, Italy, Spain) and lowest in central and east Europe (Poland, Lithuania). Over 17% of Spanish and Greek children were exposed to tobacco smoke in utero compared with only 8-11% in other countries. Caesarean section rate was highest in Greece (44%) and lowest in Spain (<3%). We found country-specific differences in antibiotic use, pet ownership, type of flooring and baby's mattress. In the EuroPrevall birth cohort study, the largest study using gold-standard diagnostic criteria for food allergy in children worldwide, we found considerable country-specific baseline differences regarding a wide range of factors that are hypothesized to play a role in the development of food allergy including allergic family history, obstetrical practices, pre- and post-natal environmental exposures.