Pandemrix® vaccination is not associated with increased risk of islet autoimmunity or type 1 diabetes in the TEDDY study children

Looking back at the TEDDY study: lessons and future directions

The goal of the TEDDY (The Environmental Determinants of Diabetes in the Young) study is to elucidate factors leading to the initiation of islet autoimmunity (first primary outcome) and those related to progression to type 1 diabetes mellitus (T1DM; second primary outcome). This Review outlines the key findings so far, particularly related to the first primary outcome. The background, history and organization of the study are discussed. Recruitment and follow-up (from age 4 months to 15 years) of 8,667 children showed high retention and compliance. End points of the presence of autoantibodies against insulin, GAD65, IA-2 and ZnT8 revealed the HLA-associated early appearance of insulin autoantibodies (1-3 years of age) and the later appearance of GAD65 autoantibodies. Competing autoantibodies against tissue transglutaminase (marking coeliac disease autoimmunity) also appeared early (2-4 years). Genetic and environmental factors, including enterovirus infection and gastroenteritis, support mechanistic differences underlying one phenotype of autoimmunity against insulin and another against GAD65. Infant growth and both probiotics and high protein intake affect the two phenotypes differently, as do serious life events during pregnancy. As the end of the TEDDY sampling phase is approaching, major omics approaches are in progress to further dissect the mechanisms that might explain the two possible endotypes of T1DM.

Rotavirus Vaccination Protects Against Diabetes Mellitus Type 1 in Children in Developed Countries: A Systematic Review and Meta-Analysis

Background: The etiology of type 1 diabetes (T1D) remains an area of active research, with genetic and environmental factors being investigated. This meta-analysis aimed to determine if rotavirus vaccination influences the onset of T1D in children. Methods: Following PRISMA 2020 guidelines, two researchers independently searched multiple databases, including PubMed and Google Scholar, for studies published in English from 2006 to September 2024. They used the search terms "rotavirus vaccination" and "type 1 diabetes", and assessed study quality using the ROBINS-E tool. The analysis pooled hazard ratios (HRs) from selected studies using a fixed-effects model, with statistical significance set at p < 0.05 and heterogeneity evaluated using the I2 statistic. Results: A systematic search identified 90 records, of which 5 studies met the inclusion criteria. These studies, encompassing a total population of 4,427,291 children from developed countries, suggest a protective effect of rotavirus vaccination against T1D. The pooled HR was 0.87 (95% CI: 0.78-0.98), indicating a 13% lower risk of T1D in vaccinated children compared to unvaccinated ones (p = 0.03). Moderate heterogeneity was noted (χ2 = 10.02, df = 4, p = 0.04, I2 = 60%). Conclusions: This analysis suggests that rotavirus vaccination may reduce the risk of T1D in children from high-income Western countries. While these findings are promising, they may not be generalizable to settings outside similar advanced healthcare systems. Further research is needed to confirm the protective effects of rotavirus vaccination against T1D across diverse populations.

Understanding genetic variants in context

Over the last three decades, human genetics has gone from dissecting high-penetrance Mendelian diseases to discovering the vast and complex genetic etiology of common human diseases. In tackling this complexity, scientists have discovered the importance of numerous genetic processes - most notably functional regulatory elements - in the development and progression of these diseases. Simultaneously, scientists have increasingly used multiplex assays of variant effect to systematically phenotype the cellular consequences of millions of genetic variants. In this article, we argue that the context of genetic variants - at all scales, from other genetic variants and gene regulation to cell biology to organismal environment - are critical components of how we can employ genomics to interpret these variants, and ultimately treat these diseases. We describe approaches to extend existing experimental assays and computational approaches to examine and quantify the importance of this context, including through causal analytic approaches. Having a unified understanding of the molecular, physiological, and environmental processes governing the interpretation of genetic variants is sorely needed for the field, and this perspective argues for feasible approaches by which the combined interpretation of cellular, animal, and epidemiological data can yield that knowledge.

INfluenza VaccInation To mitigate typE 1 Diabetes (INVITED): a study protocol for a randomised, double-blind, placebo-controlled clinical trial in children and adolescents with recent-onset type 1 diabetes

INTRODUCTION

Children and adolescents with recent-onset type 1 diabetes (T1D) commonly maintain a certain level of insulin production during the remission phase, which can last months to years. Preserving β-cell function can reduce T1D complications and improve glycaemic control. Influenza vaccination has pleiotropic effects and administration of the vaccine during the early phases of T1D may offer β-cell protection. This study aims to assess the effect of influenza vaccination on preserving β-cell function in children and adolescents with recent-onset T1D.

METHODS AND ANALYSIS

The INfluenza VaccInation To mitigate typE 1 Diabetes trial is a randomised, double-blind, placebo-controlled, multicentre trial in paediatric patients with recent-onset T1D aged 7-17 years. 100 participants will be randomised in a 1:1 ratio to receive either a standard inactivated quadrivalent influenza vaccine or a placebo within 14 days of diagnosis. The primary outcome is a difference in mean change (from baseline to 12 months) in C-peptide level between groups during a 2-hour mixed-meal tolerance test. Secondary outcomes include mean change (from baseline to 6 months) in C-peptide levels, haemoglobin A1c, ambulatory glucose profiles and insulin requirements. Exploratory outcomes are diabetes-related autoantibodies, inflammatory markers and serum haemagglutinin inhibition antibody titres against the influenza viruses. The current treatment for T1D is largely symptomatic, relying on insulin administration. There is a pressing need for novel pharmacological approaches aimed at modulating the immune system to preserve residual β-cell function. Existing immunotherapies are cost-prohibitive and associated with multiple side effects, whereas influenza vaccination is inexpensive and generally well tolerated. A positive outcome of this study holds potential for immediate implementation into standard care for children and adolescents with recent-onset T1D and may guide future research on immune modulation in T1D.

ETHICS AND DISSEMINATION

Ethical approval was obtained from Danish Health Authorities prior to participant enrollment. The trial results will be submitted to a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT05585983 and EudraCT Number 2022-500906-17-01.

Specific and Nonspecific Effects of Influenza Vaccines

With the introduction of the influenza vaccine in the official immunization schedule of most countries, several data regarding the efficacy, tolerability, and safety of influenza immunization were collected worldwide. Interestingly, together with the confirmation that influenza vaccines are effective in reducing the incidence of influenza virus infection and the incidence and severity of influenza disease, epidemiological data have indicated that influenza immunization could be useful for controlling antimicrobial resistance (AMR) development. Knowledge of the reliability of these findings seems essential for precise quantification of the clinical relevance of influenza immunization. If definitively confirmed, these findings can have a relevant impact on influenza vaccine development and use. Moreover, they can be used to convince even the most recalcitrant health authorities of the need to extend influenza immunization to the entire population. In this narrative review, present knowledge regarding these particular aspects of influenza immunization is discussed. Literature analysis showed that the specific effects of influenza immunization are great enough per se to recommend systematic annual immunization of younger children, old people, and all individuals with severe chronic underlying diseases. Moreover, influenza immunization can significantly contribute to limiting the emergence of antimicrobial resistance. The problem of the possible nonspecific effects of influenza vaccines remains unsolved. The definition of their role as inducers of trained immunity seems essential not only to evaluate how much they play a role in the prevention of infectious diseases but also to evaluate whether they can be used to prevent and treat clinical conditions in which chronic inflammation and autoimmunity play a fundamental pathogenetic role.

Pleiotropic Effects of Influenza Vaccination

Influenza vaccines are designed to mimic natural influenza virus exposure and stimulate a long-lasting immune response to future infections. The evolving nature of the influenza virus makes vaccination an important and efficacious strategy to reduce healthcare-related complications of influenza. Several lines of evidence indicate that influenza vaccination may induce nonspecific effects, also referred to as heterologous or pleiotropic effects, that go beyond protection against infection. Different explanations are proposed, including the upregulation and downregulation of cytokines and epigenetic reprogramming in monocytes and natural killer cells, imprinting an immunological memory in the innate immune system, a phenomenon termed "trained immunity". Also, cross-reactivity between related stimuli and bystander activation, which entails activation of B and T lymphocytes without specific recognition of antigens, may play a role. In this review, we will discuss the possible nonspecific effects of influenza vaccination in cardiovascular disease, type 1 diabetes, cancer, and Alzheimer's disease, future research questions, and potential implications. A discussion of the potential effects on infections by other pathogens is beyond the scope of this review.

Possible heterogeneity of initial pancreatic islet beta-cell autoimmunity heralding type 1 diabetes

The etiology of type 1 diabetes (T1D) foreshadows the pancreatic islet beta-cell autoimmune pathogenesis that heralds the clinical onset of T1D. Standardized and harmonized tests of autoantibodies against insulin (IAA), glutamic acid decarboxylase (GADA), islet antigen-2 (IA-2A), and ZnT8 transporter (ZnT8A) allowed children to be followed from birth until the appearance of a first islet autoantibody. In the Environmental Determinants of Diabetes in the Young (TEDDY) study, a multicenter (Finland, Germany, Sweden, and the United States) observational study, children were identified at birth for the T1D high-risk HLA haploid genotypes DQ2/DQ8, DQ2/DQ2, DQ8/DQ8, and DQ4/DQ8. The TEDDY study was preceded by smaller studies in Finland, Germany, Colorado, Washington, and Sweden. The aims were to follow children at increased genetic risk to identify environmental factors that trigger the first-appearing autoantibody (etiology) and progress to T1D (pathogenesis). The larger TEDDY study found that the incidence rate of the first-appearing autoantibody was split into two patterns. IAA first peaked already during the first year of life and tapered off by 3-4 years of age. GADA first appeared by 2-3 years of age to reach a plateau by about 4 years. Prior to the first-appearing autoantibody, genetic variants were either common or unique to either pattern. A split was also observed in whole blood transcriptomics, metabolomics, dietary factors, and exposures such as gestational life events and early infections associated with prolonged shedding of virus. An innate immune reaction prior to the adaptive response cannot be excluded. Clarifying the mechanisms by which autoimmunity is triggered to either insulin or GAD65 is key to uncovering the etiology of autoimmune T1D.

Narcolepsy among first- and second-generation immigrants in Sweden: A study of the total population

Aims

To study incident narcolepsy in first‐ and second‐generation immigrant groups using Swedish‐born individuals and native Swedes as referents.

Methods

The study population included all individuals registered and alive in Sweden at baseline. Narcolepsy was defined as having at least one registered diagnosis of narcolepsy in the Swedish National Patient Register. The incidence of narcolepsy in different immigrant groups was assessed by Cox regression, with hazard ratios (HRs) and 95% confidence intervals (CI). The models were stratified by sex and adjusted for age, geographical residence in Sweden, educational level, marital status, co‐morbidities, and neighbourhood socioeconomic status.

Results

In the first‐generation study, 1225 narcolepsy cases were found; 465 males and 760 females, and in the second‐generation study, 1710 cases, 702 males and 1008 females. Fully adjusted HRs (95% CI) in the first‐generation study was for males 0.83 (0.61–1.13) and females 0.83 (0.64–1.07), and in the second‐generation study for males 0.76 (0.60–0.95) and females 0.91 (95% CI 0.76–1.09). Statistically significant excess risks of narcolepsy were found in first‐generation males from North America, and second‐generation males with parents from North America, and second‐generation females with parents from Latin America.

Conclusions

There were only significant differences in incident narcolepsy between native Swedes and second‐generation male immigrants. The observed differences can partly be explained by differences in Pandemrix® vaccinations and are probably not attributable to genetic differences between immigrants and natives.

Endocrine system after 2 years of COVID-19 vaccines: A narrative review of the literature

PURPOSE

The purpose of this study was to describe the current knowledge on the potential endocrine adverse effects post-COVID-19 vaccines.

METHODS

A PubMed/MEDLINE, Web of Science, and Scopus research was performed. Case reports, case series, original studies, and reviews written in English and published online up to 31 July 2022 were selected and reviewed. The final reference list was defined based on the relevance of each paper to the scope of this review.

RESULTS

The available data showed that endocrine side effects are generally rare and with favorable outcome, being thyroid disorders the most common. Conversely, data on type 1 diabetes mellitus are rare; adrenal and pituitary events are even anecdotal. Finally, the available clinical studies suggest no impact on female reproductive system and on male and couple fertility.

CONCLUSION

Overall, these data show that, after 2 years of COVID-19 vaccines, the endocrine system is not heavily threatened.

Environmental Determinants of Type 1 Diabetes: From Association to Proving Causality

The rising incidence of type 1 diabetes (T1D) cannot be ascribed to genetics alone, and causative environmental triggers and drivers must also be contributing. The prospective TEDDY study has provided the greatest contributions in modern time, by addressing misconceptions and refining the search strategy for the future. This review outlines the evidence to date to support the pathways from association to causality, across all stages of T1D (seroconversion to beta cell failure). We focus on infections and vaccinations; infant growth and childhood obesity; the gut microbiome and the lifestyle factors which cultivate it. Of these, the environmental determinants which have the most supporting evidence are enterovirus infection, rapid weight gain in early life, and the microbiome. We provide an infographic illustrating the key environmental determinants in T1D and their likelihood of effect. The next steps are to investigate these environmental triggers, ideally though gold-standard randomised controlled trials and further prospective studies, to help explore public health prevention strategies.

Association between influenza and the incidence rate of new-onset type 1 diabetes in Japan

AIM

This study aimed to determine whether there is an association between influenza and new-onset type 1 diabetes.

MATERIALS AND METHODS

This population-based retrospective cohort study used data from the National Database of Health Insurance Claims and Specific Health Check-ups of Japan. Influenza was defined based on drug prescriptions and the onset of type 1 diabetes was defined using specific medical codes indicating a diagnosis of type 1 diabetes. The incidence rate ratio of new-onset type 1 diabetes within 180 days after an influenza diagnosis was calculated and it was compared with that at other times using Poisson regression and generalized estimating equations. Sensitivity analyses were performed to confirm the robustness of this finding.

RESULTS

The data of 10,400 patients with new-onset type 1 diabetes were analyzed, including 2,196 (952 male 1,244 female) patients diagnosed with influenza between 1 September 2014 and 31 August 2017. Although only patients with type 1 diabetes were included, adjusted analysis showed that individuals had a 1.3-fold (95% confidence interval: 1.15-1.46) higher risk of developing type 1 diabetes in the first 180 days after influenza diagnosis than that at other times.

CONCLUSIONS

In this Japanese population-based cohort, the risk of new-onset type 1 diabetes may increase after the diagnosis of influenza. These results, which must be confirmed in other populations, suggest that influenza may be a causal factor for new-onset type 1 diabetes. The molecular mechanisms underlying the potential etiological relationship between influenza and type 1 diabetes should be elucidated.

The Multifactorial Progression from the Islet Autoimmunity to Type 1 Diabetes in Children

Type 1 Diabetes (T1D) results from autoimmune destruction of insulin producing pancreatic ß-cells. This disease, with a peak incidence in childhood, causes the lifelong need for insulin injections and necessitates careful monitoring of blood glucose levels. However, despite the current insulin therapies, it still shortens life expectancy due to complications affecting multiple organs. Recently, the incidence of T1D in childhood has increased by 3-5% per year in most developed Western countries. The heterogeneity of the disease process is supported by the findings of follow-up studies started early in infancy. The development of T1D is usually preceded by the appearance of autoantibodies targeted against antigens expressed in the pancreatic islets. The risk of T1D increases significantly with an increasing number of positive autoantibodies. The order of autoantibody appearance affects the disease risk. Genetic susceptibility, mainly defined by the human leukocyte antigen (HLA) class II gene region and environmental factors, is important in the development of islet autoimmunity and T1D. Environmental factors, mainly those linked to the changes in the gut microbiome as well as several pathogens, especially viruses, and diet are key modulators of T1D. The aim of this paper is to expand the understanding of the aetiology and pathogenesis of T1D in childhood by detailed description and comparison of factors affecting the progression from the islet autoimmunity to T1D in children.

Sodium-glucose cotransporter inhibitors as add-on therapy in addition to insulin for type 1 diabetes mellitus: A meta-analysis of randomized controlled trials

AIMS/INTRODUCTION

Several clinical trials reported the effects of sodium-glucose cotransporter (SGLT) inhibitors in type 1 diabetes patients. This meta-analysis aimed to assess the efficacy and safety of SGLT inhibitors in type 1 diabetes patients.

MATERIALS AND METHODS

Relevant studies were identified in the PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure and Wan Fang databases through 1 April 2020. Differences were expressed as the 95% confidence interval (CI) or weighted mean difference (WMD) for continuous outcomes, and risk ratio (RR) for discontinuous outcomes.

RESULTS

A total of 13 RCTs with 7,962 cases were included. SGLT inhibitors reduced the fasting plasma glucose level (WMD -1.320 mmol/L, 95% CI -1.609 to -1.031, P < 0.001), glycated hemoglobin level (WMD -0.386%, 95% CI -0.431 to -0.342, P < 0.001) and daily total insulin dose (WMD -5.403, 95% CI -7.218 to -3.859, P < 0.001). However, higher risks of diabetic ketoacidosis (RR 5.042, 95% CI 3.160-8.046, P < 0.001), urinary tract infections (RR 1.259, 95% CI 1.034-1.533,P = 0.022) and genital infections (RR 2.995, 95% CI 1.953-4.594, P < 0.001) were associated with SGLT inhibitors, but SGLT inhibitors did not increase the hypoglycemia risk (RR 0.980, 95% CI 0.840-1.144,P = 0.799). In subgroup analysis, with a significant reduction of fasting plasma glucose, glycated hemoglobin and daily insulin doses, SGLT1/2 inhibitor did not increase genitourinary tract infections compared with a placebo.

CONCLUSIONS

SGLT2 and SGLT1/2 inhibitors can improve glycemic control in patients with type 1 diabetes.

Caring for children and adolescents with type 1 diabetes mellitus: Italian Society for Pediatric Endocrinology and Diabetology (ISPED) statements during COVID-19 pandemia

AIMS

Our study aimed to review the impact of COVID-19 pandemia in children and adolescents with type 1 diabetes mellitus, to analyze the clinical characteristics of the infection and to propose clinical practice recommendations from the Italian Society for Pediatric Endocrinology and Diabetology (ISPED).

METHODS

A literature search was carried out in the guideline databases, Medline and Embase and in Diabetes Societies websites until May 21st, 2020 for guidelines and recommendations on type 1 diabetes mellitus management during COVID-19 pandemic.

RESULTS

COVID-19 infection in pediatric patients seems to be clinically less severe than in adults; children have so far accounted for 1-5% of diagnosed cases, with a median age of 6.7 years (1 day-15 years) and better prognosis. Clinical manifestations include mild, moderate, severe disease up to critical illness. There is currently no evidence suggesting a higher risk of COVID-19 infection in children with diabetes than unaffected peers. Besides general recommendations for pediatric patients, ISPED has proposed specific measures for patients with diabetes.

CONCLUSION

COVID-19 outbreak modified type 1 diabetes management, and telemedicine has been demonstrating to be an effective new tool for patients care. Moreover psychological aspects deserve attention and future researchs are mandatory.

The Environmental Determinants of Diabetes in the Young (TEDDY) Study: 2018 Update

PURPOSE OF REVIEW

The environmental triggers of islet autoimmunity leading to type 1 diabetes (T1D) need to be elucidated to inform primary prevention. The Environmental Determinants of Diabetes in the Young (TEDDY) Study follows from birth 8676 children with T1D risk HLA-DR-DQ genotypes in the USA, Finland, Germany, and Sweden. Most study participants (89%) have no first-degree relative with T1D. The primary outcomes include the appearance of one or more persistent islet autoantibodies (islet autoimmunity, IA) and clinical T1D.

RECENT FINDINGS

As of February 28, 2018, 769 children had developed IA and 310 have progressed to T1D. Secondary outcomes include celiac disease and autoimmune thyroid disease. While the follow-up continues, TEDDY has already evaluated a number of candidate environmental triggers, including infections, probiotics, micronutrient, and microbiome. TEDDY results suggest that there are multiple pathways leading to the destruction of pancreatic beta-cells. Ongoing measurements of further specific exposures, gene variants, and gene-environment interactions and detailed "omics" studies will provide novel information on the pathogenesis of T1D.

Pandemic influenza and subsequent risk of type 1 diabetes: a nationwide cohort study

AIMS/HYPOTHESIS

Case reports have linked influenza infections to the development of type 1 diabetes. We investigated whether pandemic and seasonal influenza infections were associated with subsequent increased risk of type 1 diabetes.

METHODS

In this population-based registry study, we linked individual-level data from national health registries for the entire Norwegian population under the age of 30 years for the years 2006-2014 (2.5 million individuals). Data were obtained from the National Registry (population data), the Norwegian Patient Registry (data on inpatient and outpatient specialist care), the Primary Care Database, the Norwegian Prescription Database and the Norwegian Surveillance System for Communicable Diseases. Pandemic influenza was defined as either a clinical influenza diagnosis during the main pandemic period or a laboratory-confirmed test. Seasonal influenza was defined by a clinical diagnosis of influenza between 2006 and 2014. We used Cox regression to estimate HRs for new-onset type 1 diabetes after an influenza infection, adjusted for year of birth, sex, place of birth and education.

RESULTS

The adjusted HR for type 1 diabetes after pandemic influenza infection was 1.19 (95% CI 0.97, 1.46). In the subgroup with laboratory-confirmed influenza A (H1N1), influenza was associated with a twofold higher risk of subsequent type 1 diabetes before age 30 years (adjusted HR: 2.26, 95% CI 1.51, 3.38).

CONCLUSIONS/INTERPRETATION

Overall, we could not demonstrate a clear association between clinically reported pandemic influenza infection and incident type 1 diabetes. However, we found a twofold excess of incident diabetes in the subgroup with laboratory-confirmed pandemic influenza A (H1N1).