A randomized, placebo-controlled, double-blinded, single-centre, phase IV trial to assess the efficacy and safety of OM-85 in children suffering from recurrent respiratory tract infections

PROTEA study: a protocol for a randomised controlled trial evaluating the efficacy, immune effects and cost-effectiveness of oral bacterial lysate therapy to protect moderate-late preterm infants from respiratory tract infections and wheezing

Infants, children and adults born moderate-late preterm (after 30-36 weeks of pregnancy) are at increased risk of respiratory infections, wheezing and lower lung function leading to increased medication use and hospitalisation. Risk factors frequently present in this population are, at least in part, associated with (lack of) exposure to microbes and subsequent perturbations in microbiome and immune system development. This manuscript presents the protocol of the double-blinded randomised placebo-controlled PROTEA trial, which will demonstrate whether treatment with immunomodulatory bacterial lysates (OM-85) can reduce lower respiratory tract infections and wheeze in the first year of life. The follow-up PROTEA-2 trial will identify possible carry-over effects of OM-85 treatment and investigate the clinical effect of continued treatment in the second year of life. Infants included are otherwise healthy infants born after 30-36 weeks of gestation, excluding those small for gestational age (<3rd percentile). They are recruited shortly after birth in 22 medical centres in the Netherlands. Participants will take OM-85 or placebo starting from 6-10 weeks of life till age 1 year (PROTEA study) or 2 years (PROTEA-2 study) and are closely monitored regarding respiratory health through e-applications. Biological samples, lung function measurements and detailed information on covariates will be collected at ages 2, 6, 12 and 24 months. Biological samples will aid in estimating the impact of bacterial lysate administration on immune cell composition, activation and maturation, vaccination responses, and microbiome diversity and maturation. Participant recruitment started in March 2022.

OM-85 attenuates high-fat diet-induced obesity, insulin resistance, gut dysbiosis and nonalcoholic steatohepatitis in a murine model

BACKGROUND

Obesity is a global epidemic that is tied to a wide range of human disorders. Chronic consumption of a high-fat diet is linked to disruption of the intestinal microbiome, which drives obesity-related pathophysiology. Broncho-Vaxom® (OM-85), a bacterial lysate used for prophylaxis of recurrent respiratory tract infections, has both immunostimulatory and immunomodulatory functions.

METHODS

Male C57Bl/6 mice were maintained on normal control vs. high-fat diets for 8 weeks and treated or untreated with OM-85 or with the probiotic Lactobacillus plantarum, as a positive control. Mice were evaluated for weight gain, glucose tolerance, insulin tolerance, gut microbiome composition and non-alcoholic steatohepatitis (NASH).

RESULTS

High-fat diet mice developed obesity, insulin resistance, NASH and gut dysbiosis with a shift from the Bacteroidetes phylum, such as Bacteroidales order and Muribaculaceae family organisms to Firmicutes groups, such as the Clostridium and Blautia genuses. Treatment with OM-85 led to 1) prevention of obesity, 2) prevention of insulin resistance, 3) attenuation of NASH and 4) attenuation of gut dysbiosis, with decreased levels of the organisms mentioned above and increases in Verrucomicrobiae phylum organisms such as Akkermansia family microbes as well as Muribaculaceae organisms. These shifts in the gut microbiome predict favorable effects on the short chain fatty acid profile in the gut and increased integrity of the intestinal barrier. Pathway analysis showed that OM-85 decreases rates of carbohydrate metabolism, providing an additional mechanism whereby OM-85 prevents obesity.

CONCLUSION

Immune modulators such as OM-85 should be investigated for their potential therapeutic effects on metabolism.

Is There a Role for Immunostimulant Bacterial Lysates in the Management of Respiratory Tract Infection?

Bacterial Lysates are immunostimulants clinically prescribed for the prevention of respiratory tract infections (RTIs). It has been shown that Bacterial Lysates upregulate the immune system, acting both on innate and adaptive reactions. In fact, there are demonstrations of their efficacy in restoring the integrity and immune function of epithelial barriers, activating ILC3 and dendritic cells with an enhanced Th1 response, and producing serum IgG and serum and salivary IgA specific to the administered bacterial antigens. The activated immune system also protects against other bacteria and viruses due to a trained immunity effect. Most studies show that the number of RTIs and their severity decrease in Bacterial Lysates-pretreated patients, without relevant side effects. The Bacterial Lysates treatment, in addition to reducing the number of RTIs, also prevents the deterioration of the underlying disease (i.e., COPD) induced by repeated infections. Despite these positive data, the most recent meta-analyses evidence the weakness of the studies performed, which are of low quality and have an inadequate number of patients, some of which were non-randomized while others were without a control group or were performed contemporarily in different clinical conditions or with different ages. The high heterogeneity of the studies does not allow us to state Bacterial Lysates' effectiveness in preventing RTIs with sufficient certainty. To completely define their indications, double-blind, placebo-controlled, multicenter, randomized clinical trials should be performed for each product and for each indication. The study population should be adequate for each indication. For this purpose, an adequate run-in phase will be necessary.

The bacterial lysate OM-85 engages Toll-like receptors 2 and 4 triggering an immunomodulatory gene signature in human myeloid cells

OM-85 is a bacterial lysate used in clinical practice to reduce duration and frequency of recurrent respiratory tract infections. Whereas knowledge of its regulatory effects in vivo has substantially advanced, the mechanisms of OM-85 sensing remain inadequately addressed. Here, we show that the immune response to OM-85 in the mouse is largely mediated by myeloid immune cells through Toll-like receptor (TLR) 4 in vitro and in vivo. Instead, in human immune cells, TLR2 and TLR4 orchestrate the response to OM-85, which binds to both receptors as shown by surface plasmon resonance assay. Ribonucleic acid-sequencing analyses of human monocyte-derived dendritic cells reveal that OM-85 triggers a pro-inflammatory signature and a unique gene set, which is not induced by canonical agonists of TLR2 or TLR4 and comprises tolerogenic genes. A largely overlapping TLR2/4-dependent gene signature was observed in individual subsets of primary human airway myeloid cells, highlighting the robust effects of OM-85. Collectively, our results suggest caution should be taken when relating murine studies on bacterial lysates to humans. Furthermore, our data shed light on how a standardized bacterial lysate shapes the response through TLR2 and TLR4, which are crucial for immune response, trained immunity, and tolerance.

Preventive effects of prenatal administration of OM-85/BV on asthma and respiratory infection risk in the offspring: A review of animal models

Asthma is the most common chronic disease in childhood affecting the daily lives of many patients despite current treatment regimens. Therefore, the need for new therapeutic approaches is evident, where a primary prevention strategy is the ultimate goal. Studies of children born to mothers in farming environments have shown a lower risk of respiratory infections and asthma development. Already at birth, these newborns have demonstrated accelerated maturation and upregulation of host defense immune functions suggesting a prenatal transplacental training of the innate immune system through maternal microbial exposure. This mechanism could possibly be utilized to help prevent both respiratory infections and asthma in young children. Human studies exploring the potential preventative effects of pregnancy bacterial lysate treatment on asthma and respiratory infections are lacking, however, this has been studied in experimental studies using mice through administrations of the bacterial lysate OM-85. This review will present the current literature on the immunomodulatory effects relevant for respiratory infections and asthma in the offspring of mice treated with OM-85 throughout pregnancy. Further, the review will discuss the cellular and molecular mechanisms behind these effects. In conclusion, we found promising results of an accelerated immune competence and improved resistance to airway challenges as a result of prenatal bacterial lysate treatment that may pave the way for implementing this in human trials to prevent asthma and respiratory infections.

Insights into the role of the respiratory tract microbiome in defense against bacterial pneumonia

The respiratory tract microbiome (RTM) is a microbial ecosystem inhabiting different niches throughout the airway. A critical role for the RTM in dictating lung infection outcomes is underlined by recent efforts to identify community members benefiting respiratory tract health. Obligate anaerobes common in the oropharynx and lung such as Prevotella and Veillonella are associated with improved pneumonia outcomes and activate several immune defense pathways in the lower airway. Colonizers of the nasal cavity, including Corynebacterium and Dolosigranulum, directly impact the growth and virulence of lung pathogens, aligning with robust clinical correlations between their upper airway abundance and reduced respiratory tract infection risk. Here, we highlight recent work identifying respiratory tract bacteria that promote airway health and resilience against disease, with a focus on lung infections and the underlying mechanisms driving RTM-protective benefits.

Bacterial immunotherapy is highly effective in reducing recurrent upper respiratory tract infections in children: a prospective observational study

PURPOSE

Whilst immunotherapy is an appealing option as it could reduce the burden of recurrent pediatric respiratory tract infections (RTI), there is limited evidence on its effectiveness and more research was requested in order to better understand this therapeutic modality.

METHODS

We performed a prospective cohort study involving 57 subjects to assess the safety and effectiveness a 3-month regimen of either typified or patient-specific bacterial lysates could have in reducing the number of RTIs in children aged 0 to 11 years with histories of recurrent episodes.

RESULTS

After a 6-month follow-up, the number of RTIs and school absenteeism dropped sharply and significantly, from an adjusted mean (standard error) of 0.6 (0.04) episodes/month to 0.1 (0.03) episodes/month (74.7% reduction, P < 0.001), and from an adjusted mean score of 4.6 (1.06) points to 0.0 (0.01) points over 10 (99.5% reduction, P < 0.001), respectively. There was also a significant decrease in the severity of symptoms. No adverse reactions were observed.

CONCLUSION

The use of the study product is associated with a decreased risk of recurrent RTIs in children, with a very favorable safety profile that warrants further investigation in randomized clinical trials.

ERS International Congress 2022: highlights from the Paediatrics Assembly

This review has been prepared by the Early Career Members and Chairs of the European Respiratory Society (ERS) Assembly 7: Paediatrics. We here summarise the highlights of the advances in paediatric respiratory research presented at the ERS International Congress 2022. The eight scientific groups of this Assembly cover a wide range of research areas, including respiratory physiology and sleep, asthma and allergy, cystic fibrosis (CF), respiratory infection and immunology, neonatology and intensive care, respiratory epidemiology, bronchology, and lung and airway developmental biology. Specifically, we report on abstracts presented at the congress on the effect of high altitude on sleep, sleep disorders, the hypoxic challenge test, and measurements of ventilation inhomogeneity. We discuss prevention of preschool wheeze and asthma, and new asthma medications. In children with CF, we describe how to monitor the effect of CF transmembrane conductance regulator modulator therapy. We present respiratory manifestations and chronic lung disease associated with common variable immunodeficiency. Furthermore, we discuss how to monitor respiratory function in neonatal and paediatric intensive care units. In respiratory epidemiology, we present the latest news from population-based and clinical cohort studies. We also focus on innovative and interventional procedures for the paediatric airway, such as cryotherapy. Finally, we stress the importance of better understanding the molecular mechanisms underlying normal and abnormal lung development.

Vaccines for the common cold

BACKGROUND

The common cold is a spontaneously remitting infection of the upper respiratory tract, characterised by a runny nose, nasal congestion, sneezing, cough, malaise, sore throat, and fever (usually < 37.8 ºC). Whilst the common cold is generally not harmful, it is a cause of economic burden due to school and work absenteeism. In the United States, economic loss due to the common cold is estimated at more than USD 40 billion per year, including an estimate of 70 million workdays missed by employees, 189 million school days missed by children, and 126 million workdays missed by parents caring for children with a cold. Additionally, data from Europe show that the total cost per episode may be up to EUR 1102. There is also a large expenditure due to inappropriate antimicrobial prescription. Vaccine development for the common cold has been difficult due to antigenic variability of the common cold viruses; even bacteria can act as infective agents. Uncertainty remains regarding the efficacy and safety of interventions for preventing the common cold in healthy people, thus we performed an update of this Cochrane Review, which was first published in 2011 and updated in 2013 and 2017.

OBJECTIVES

To assess the clinical effectiveness and safety of vaccines for preventing the common cold in healthy people.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (April 2022), MEDLINE (1948 to April 2022), Embase (1974 to April 2022), CINAHL (1981 to April 2022), and LILACS (1982 to April 2022). We also searched three trials registers for ongoing studies, and four websites for additional trials (April 2022). We did not impose any language or date restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of any virus vaccine compared with placebo to prevent the common cold in healthy people.

DATA COLLECTION AND ANALYSIS

We used Cochrane's Screen4Me workflow to assess the initial search results. Four review authors independently performed title and abstract screening to identify potentially relevant studies. We retrieved the full-text articles for those studies deemed potentially relevant, and the review authors independently screened the full-text reports for inclusion in the review, recording reasons for exclusion of the excluded studies. Any disagreements were resolved by discussion or by consulting a third review author when needed. Two review authors independently collected data on a data extraction form, resolving any disagreements by consensus or by involving a third review author. We double-checked data transferred into Review Manager 5 software. Three review authors independently assessed risk of bias using RoB 1 tool as outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We carried out statistical analysis using Review Manager 5. We did not conduct a meta-analysis, and we did not assess publication bias. We used GRADEpro GDT software to assess the certainty of the evidence and to create a summary of findings table.  MAIN RESULTS: We did not identify any new RCTs for inclusion in this update. This review includes one RCT conducted in 1965 with an overall high risk of bias. The RCT included 2307 healthy young men in a military facility, all of whom were included in the analyses, and compared the effect of three adenovirus vaccines (live, inactivated type 4, and inactivated type 4 and 7) against a placebo (injection of physiological saline or gelatin capsule). There were 13 (1.14%) events in 1139 participants in the vaccine group, and 14 (1.19%) events in 1168 participants in the placebo group. Overall, we do not know if there is a difference between the adenovirus vaccine and placebo in reducing the incidence of the common cold (risk ratio 0.95, 95% confidence interval 0.45 to 2.02; very low-certainty evidence). Furthermore, no difference in adverse events when comparing live vaccine preparation with placebo was reported. We downgraded the certainty of the evidence to very low due to unclear risk of bias, indirectness because the population of this study was only young men, and imprecision because confidence intervals were wide and the number of events was low. The included study did not assess vaccine-related or all-cause mortality.  AUTHORS' CONCLUSIONS: This Cochrane Review was based on one study with very low-certainty evidence, which showed that there may be no difference between the adenovirus vaccine and placebo in reducing the incidence of the common cold. We identified a need for well-designed, adequately powered RCTs to investigate vaccines for the common cold in healthy people. Future trials on interventions for preventing the common cold should assess a variety of virus vaccines for this condition, and should measure such outcomes as common cold incidence, vaccine safety, and mortality (all-cause and related to the vaccine).

Expert consensus on the role of OM-85 in the management of recurrent respiratory infections: A Delphi study

Recurrent infections of upper and lower respiratory tract have an important clinical and economic impact, which can be reduced through appropriate preventive measures, including the use of immunomodulating agents, such as OM-85, which proved to be effective and safe in both adults and children. Although OM-85 can be useful for the prevention of respiratory tract infections, it is still underused in clinical practice. In order to evaluate the level of awareness of the disease burden of recurrent respiratory infections in adults and children and to assess the level of agreement on the prophylactic and therapeutic approach to the disease, including the use of immunomodulants, a Delphi study was performed. A board of six experts in the field of respiratory infections was appointed to elaborate a series of statements covering four main topics (disease, prevention, OM-85, and future strategies), which were thereafter voted by a panel of 30 experts. Results showed that prevention is unanimously recognized as the most important intervention to reduce disease burden, and the use of immunomodulation to improve the effectiveness of vaccination is gaining increasing favor among clinicians. In this respect, OM-85 is recognized as the most studied immunomodulating agent currently available, whose efficacy and safety make it a valuable tool to optimize the management of recurrent respiratory infections in both adults and children. In particular, the combined use of OM-85 and influenza vaccine was recognized as an effective and safe approach to improve the current prevention strategies in order to reduce the burden of recurrent respiratory infections.

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

Establishing Healthy Lifestyle Choices Early: How to Counsel Children and Their Parents

Promoting childhood and adolescent health and long-term well-being requires an emphasis on preventative care and anticipatory guidance. In this review, the authors will focus on pertinent ear, nose, and throat preventative health in children, providing clinicians with relevant and succinct information to counsel children and their parents on the following essential subjects: foreign body aspiration and ingestion, upper respiratory infection prevention, noise exposure risks, aural hygiene, risks of primary and secondhand smoke exposure, and sleep hygiene.

Microbiota profiles in pre-school children with respiratory infections: Modifications induced by the oral bacterial lysate OM-85

To describe microbiota profiles considering potential influencing factors in pre-school children with recurrent respiratory tract infections (rRTIs) and to evaluate microbiota changes associated with oral bacterial lysate OM-85 treatment, we analyzed gut and nasopharynx (NP) microbiota composition in patients included in the OM-85-pediatric rRTIs (OMPeR) clinical trial (https://www.clinicaltrialsregister.eu/ctr-search/trial/2016-002705-19/IT). Relative percentage abundance was used to describe microbiota profiles in all the available biological specimens, grouped by age, atopy, and rRTIs both at inclusion (T0) and at the end of the study, after treatment with OM-85 or placebo (T1). At T0, Firmicutes and Bacteriodetes were the predominant genera in gut and Proteobacteria, Firmicutes, and Actinobacteria were the predominant genera in NP samples. Gut microbiota relative composition differed with age (<2 vs. ≥2 years) for Firmicutes, Proteobacteria, Actinobacteria (phyla) and Bifidobacterium, Ruminococcus, Lachnospiraceae (genera) (p < 0.05). Moraxella was more enriched in the NP of patients with a history of up to three RTIs. Intra-group changes in relative percentage abundance were described only for patients with gut and NP microbiota analysis available at both T0 and T1 for each study arm. In this preliminary analysis, the gut microbiota seemed more stable over the 6-month study in the OM-85 group, whose mean age was lower, as compared to the placebo group (p = 0.004). In this latter group, the relative abundance of Bacteroides decreased significantly in children ≥2 years. Some longitudinal significant differences in genera relative abundance were also detected in children of ≥2 years for NP Actinobacteria, Haemophilus, and Corynebacterium in the placebo group only. Due to the small number of patients in the different sub-populations, we could not identify significant differences in the clinical outcome and therefore no associations with microbiota changes were searched. The use of bacterial lysates might play a role in microbiota rearrangement, but further data and advanced analysis are needed to prove this in less heterogeneous populations with higher numbers of samples considering the multiple influencing factors such as delivery method, age, environment, diet, antibiotic use, and type of infections to ultimately show any associations with prevention of rRTIs.

Recent advances in the concept of paraprobiotics: Nutraceutical/functional properties for promoting children health

Probiotics consumption has been associated with various health promoting benefits, including disease prevention and even treatment by modulating gut microbiota. Contrary to this, probiotics may also overstimulate the immune system, trigger systemic infections, harmful metabolic activities, and promote gene transfer. In children, the fragile immune system and impaired intestinal barrier may boost the occurrence of adverse effects following probiotics' consumption. To overcome these health challenges, the key focus has been shifted toward non-viable probiotics, also called paraprobiotics. Cell wall polysaccharides, peptidoglycans, surface proteins and teichoic acid present on cell's surface are involved in the interaction of paraprobiotics with the host, ultimately providing health benefits. Among other benefits, paraprobiotics possess the ability to regulate innate and adaptive immunity, exert anti-adhesion, anti-biofilm, anti-hypertensive, anti-inflammatory, antioxidant, anti-proliferative, and antagonistic effects against pathogens, while also enhance clinical impact and general safety when administered in children in comparison to probiotics. Clinical evidence have underlined the paraprobiotics impact in children and young infants against atopic dermatitis, respiratory and gastrointestinal infections, in addition to be useful for immunocompromised individuals. Therefore, this review focuses on probiotics-related issues in children's health and also discusses the Lactobacillus and Bifidobacterium spp. qualities for qualifying as paraprobiotics and their role in promoting the children's health.

OM-85 Broncho-Vaxom®, a Bacterial Lysate, Reduces SARS-CoV-2 Binding Proteins on Human Bronchial Epithelial Cells

In clinical studies, OM-85 Broncho-Vaxom®, a bacterial lysate, reduced viral respiratory tract infection. Infection of epithelial cells by SARS-CoV-2 depends on the interaction of its spike-protein (S-protein) with host cell membrane proteins. In this study, we investigated the effect of OM-85 on the expression of S-protein binding proteins by human bronchial epithelial cells. Human bronchial epithelial cells were treated with OM-85 over 5 days. The expression of SARS-CoV-2 receptor angiotensin converting enzyme 2 (ACE2), transmembrane protease serine subtype 2 (TMPRSS2), dipeptidyl peptidase-4 (DPP4), and a disintegrin and metalloprotease 17 (ADAM17) were determined by Western blotting and quantitative RT-PCR. Soluble (s)ACE2, heparan sulfate, heparanase, and hyaluronic acid were assessed by ELISA. OM-85 significantly reduced the expression of ACE2 (p < 0.001), TMPRSS2 (p < 0.001), DPP4 (p < 0.005), and cellular heparan sulfate (p < 0.01), while ADAM17 (p < 0.02) expression was significantly upregulated. Furthermore, OM-85 increased the level of sACE2 (p < 0.05), hyaluronic acid (p < 0.002), and hyaluronan synthase 1 (p < 0.01). Consequently, the infection by a SARS-CoV-2 spike protein pseudo-typed lentivirus was reduced in cells pretreated with OM-85. All effects of OM-85 were concentration- and time-dependent. The results suggest that OM-85 might reduce the binding of SARS-CoV-2 S-protein to epithelial cells by modification of host cell membrane proteins and specific glycosaminoglycans. Thus, OM-85 might be considered as an add-on for COVID-19 therapy.

Prevention of recurrent respiratory infections : Inter-society Consensus

Recurrent respiratory infections (RRIs) are a common clinical condition in children, in fact about 25% of children under 1 year and 6% of children during the first 6 years of life have RRIs. In most cases, infections occur with mild clinical manifestations and the frequency of episodes tends to decrease over time with a complete resolution by 12 years of age. However, RRIs significantly reduce child and family quality of life and lead to significant medical and social costs.Despite the importance of this condition, there is currently no agreed definition of the term RRIs in the literature, especially concerning the frequency and type of infectious episodes to be considered. The aim of this consensus document is to propose an updated definition and provide recommendations with the intent of guiding the physician in the complex process of diagnosis, management and prevention of RRIs.

Whether Immunostimulants Are Effective in Susceptible Children Suffering From Recurrent Respiratory Tract Infections: A Modeling Analysis Based on Literature Aggregate Data

Immunostimulants are gradually being used in the prevention and treatment of recurrent respiratory tract infections in susceptible children, but their drug effects have not been quantified. The purpose of this study was to confirm the efficacy of immunostimulants in the prevention and treatment of recurrent respiratory tract infections in susceptible children. A model-based meta-analysis was used to describe the time course of placebo and immunostimulants in the prevention of respiratory tract infections in children. The cumulative number of respiratory tract infections was used as an indicator of efficacy. A meta-analysis was used to analyze the incidence of drug-related adverse events. Fourteen articles with 2400 pediatric subjects were finally included in the analysis. The results showed that the cumulative number of respiratory tract infections increased linearly with time, with the incidence of respiratory tract infections in the placebo group being 0.65 (95% confidence interval [CI], 0.55-0.75) per month. OM-85 BV and pidotimod reduced the incidence of respiratory tract infections by 0.21 (95%CI, 0.16-0.26) and 0.19 (95%CI, 0.17-0.21) compared to placebo per month, respectively. Pidotimod and OM-85 BV can effectively reduce the incidence of respiratory tract infections in susceptible children, with no significant increase in the incidence of drug-related adverse events when compared with placebo (risk ratio values were 1.07 [95%CI, 0.66-1.71] and 1.31 [95%CI, 0.54-3.19], respectively). This study provides quantitative support for the application of immunostimulants for the prevention of recurrent respiratory tract infections in children.

Study protocol for a randomised controlled trial evaluating the clinical effect of antibiotic prophylaxis in children with recurrent respiratory tract infections: the Approach study

INTRODUCTION

Respiratory tract infections (RTIs) affect children all over the world and are associated with significant morbidity and mortality. In particular, recurrent RTIs cause a high burden of disease and lead to frequent doctor visits. Children with recurrent RTIs generally have no significant alterations or deficits in systemic immunity. In an attempt to treat the assumed bacterial component involved, they are often treated with prolonged courses of prophylactic antibiotics taken on a daily basis. Despite its common use, there is no evidence that this is beneficial. Studies assessing the clinical effectiveness of antibiotic prophylaxis as well as potential adverse effects and antibiotic resistance development, are therefore urgently needed.

METHODS AND ANALYSIS

We present a protocol for a randomised double-blind placebo-controlled trial comparing co-trimoxazole with placebo treatment in children with recurrent RTIs. A total of 158 children (aged 6 months-10 years) with recurrent RTIs without significant comorbidity will be enrolled from a minimum of 10 Dutch hospitals. One group receives co-trimoxazole 18 mg/kg two times per day (36 mg/kg/day) and the other group receives a placebo two times per day for a period of 3 months. The main objective is to determine whether antibiotic prophylaxis is more effective than placebo to prevent/reduce respiratory symptoms in children with recurrent RTIs. Respiratory symptoms will be scored by parents on a daily basis in both study arms by the use of a mobile phone application. Our primary outcome will be the number of days with at least two respiratory symptoms during the treatment.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Medical Ethics Research Committee Zuidwest Holland/LDD. A manuscript with the study results will be submitted to a peer-reviewed journal. All participants will be informed about the study results. The results of the study will inform clinical guidelines regarding the prophylactic treatment of children with recurrent RTIs.

TRIAL REGISTRATION NUMBER

NL7044.

IRF7-Associated Immunophenotypes Have Dichotomous Responses to Virus/Allergen Coexposure and OM-85-Induced Reprogramming

High risk for virus-induced asthma exacerbations in children is associated with an IRF7lo immunophenotype, but the underlying mechanisms are unclear. Here, we applied a Systems Biology approach to an animal model comprising rat strains manifesting high (BN) versus low susceptibility (PVG) to experimental asthma, induced by virus/allergen coexposure, to elucidate the mechanism(s)-of-action of the high-risk asthma immunophenotype. We also investigated potential risk mitigation via pretreatment with the immune training agent OM-85. Virus/allergen coexposure in low-risk PVG rats resulted in rapid and transient airways inflammation alongside IRF7 gene network formation. In contrast, responses in high-risk BN rats were characterized by severe airways eosinophilia and exaggerated proinflammatory responses that failed to resolve, and complete absence of IRF7 gene networks. OM-85 had more profound effects in high-risk BN rats, inducing immune-related gene expression changes in lung at baseline and reducing exaggerated airway inflammatory responses to virus/allergen coexposure. In low-risk PVG rats, OM-85 boosted IRF7 gene networks in the lung but did not alter baseline gene expression or cellular influx. Distinct IRF7-associated asthma risk immunophenotypes have dichotomous responses to virus/allergen coexposure and respond differentially to OM-85 pretreatment. Extrapolating to humans, our findings suggest that the beneficial effects OM-85 pretreatment may preferentially target those in high-risk subgroups.

Protection against neonatal respiratory viral infection via maternal treatment during pregnancy with the benign immune training agent OM-85

Objectives

Incomplete maturation of immune regulatory functions at birth is antecedent to the heightened risk for severe respiratory infections during infancy. Our forerunner animal model studies demonstrated that maternal treatment with the microbial‐derived immune training agent OM‐85 during pregnancy promotes accelerated postnatal maturation of mechanisms that regulate inflammatory processes in the offspring airways. Here, we aimed to provide proof of concept for a novel solution to reduce the burden and potential long‐term sequelae of severe early‐life respiratory viral infection through maternal oral treatment during pregnancy with OM‐85, already in widespread human clinical use.

Methods

In this study, we performed flow cytometry and targeted gene expression (RT‐qPCR) analysis on lungs from neonatal offspring whose mothers received oral OM‐85 treatment during pregnancy. We next determined whether neonatal offspring from OM‐85 treated mothers demonstrate enhanced protection against lethal lower respiratory infection with mouse‐adapted rhinovirus (vMC₀), and associated lung immune changes.

Results

Offspring from mothers treated with OM‐85 during pregnancy display accelerated postnatal seeding of lung myeloid populations demonstrating upregulation of function‐associated markers. Offspring from OM‐85 mothers additionally exhibit enhanced expression of TLR4/7 and the IL‐1β/NLRP3 inflammasome complex within the lung. These treatment effects were associated with enhanced capacity to clear an otherwise lethal respiratory viral infection during the neonatal period, with concomitant regulation of viral‐induced IFN response intensity.

Conclusion

These results demonstrate that maternal OM‐85 treatment protects offspring against lethal neonatal respiratory viral infection by accelerating development of innate immune mechanisms crucial for maintenance of local immune homeostasis in the face of pathogen challenge.

Use of the Bacterial Lysate OM-85 in the Paediatric Population in Italy: A Retrospective Cohort Study

Background: In Italy, the bacterial lysate OM-85 (Broncho-Vaxom^®, Broncho-Munal^®, Ommunal^®, Paxoral^®, Vaxoral^®) is registered for the prophylaxis of recurrent respiratory tract infections (RTIs) in adults and children above one year of age, but there are limited data on its use in the paediatric population. We aim to estimate the impact of OM-85 treatment on RTIs and antibiotic prescriptions in children. Methods: This study included children aged 1 to 14 years enrolled in Pedianet, a paediatric general practice research database, from January 2007 to June 2017, having at least one prescription of OM-85. Children with less than 12 months of follow-up before (PRE period) and after (POST period) the OM-85 prescription were excluded. The frequency of antibiotic prescriptions and the frequency of RTI episodes in the PRE and POST periods were compared through the post-hoc test. Subgroup analysis was performed in children with recurrent RTIs. Results: 1091 children received 1382 OM-85 prescriptions for a total follow-up of 619,525.5 person-years. Overall, antibiotic prescriptions decreased from a mean of 2.8 (SD (standard deviation) 2.7) prescriptions in the PRE period to a mean of 2.2 (SD 2.6) prescriptions in the POST period (p < 0.0001). RTIs decreased from a mean of 3.4 (SD 2.9) episodes in the PRE period to a mean of 2.5 (SD 2.6) episodes in the POST period (p < 0.0001). No change in antibiotic class was noted, and co-amoxiclav remained the preferred therapy in 28% of cases, followed by amoxicillin. These results were confirmed among children with recurrent RTIs. Conclusions: OM-85 is effective in preventing both antibiotic prescriptions and RTIs in children.

Efficacy and safety of OM-85 in paediatric recurrent respiratory tract infections which could have a possible protective effect on COVID-19 pandemic: A meta-analysis

INTRODUCTION

The OM-85 (Broncho-Vaxom) consumption has drawn considerable attention in the prevention of recurrent respiratory tract infections. However, it has been reported that the relationship between OM-85 consumption and recurrent respiratory tract infections is variable. This meta-analysis was performed to evaluate this relationship.

METHODS

A systematic literature search up-to May 2020 was performed and 14 studies were detected with 1859 paediatric subjects, of them 890 consumed OM-85. They were reporting relationships between OM-85 consumption and recurrent respiratory tract infections. Odds ratio (OR) or mean differences (MD) with 95% confidence intervals (CIs) was calculated to evaluate the prognostic role of OM-85 consumption and recurrent respiratory tract infections using the dichotomous or continuous method with a random or fixed-effect model.

RESULTS

OM-85 consumption was significantly related to lower frequency of respiratory tract infections (MD, -1.16; 95% CI, -1.66 to -0.65, P < .001); lower total duration of respiratory tract infections (MD, -19.51; 95% CI, -23.00 to -16.01, P < .001); lower incidence of respiratory tract infections (OR, 0.40; 95% CI, 0.21-0.77, P = .006); lower number of antibiotic courses (MD, -1.40; 95% CI, -2.63 to 0.17, P = .03); and lower antibiotic use (OR, 0.38; 95% CI, 0.29-0.52, P < .001). However, OM-85 consumption was not significantly related to adverse event rate (OR, 1.02; 95% CI, 0.52-2.03, P = .94); or to wheezing attacks frequency (MD, -0.25; 95% CI, -0.59 to 0.08, P = .14).

CONCLUSIONS

The impact of OM-85 consumption on recurrent respiratory tract infections may have a great effect as a tool to improve subjects' immunity against recurrent respiratory tract infections, which could be helpful in crucial situations, eg, COVID-19 pandemic. OM-85 non-consumers had an independent risk relationship with recurrent respiratory tract infections. This relationship forces us to recommend OM-85 consumption with those with a high risk of recurrent respiratory tract infections to avoid any possible complications.

Immunological Aspects of Diagnosis and Management of Childhood Tuberculosis

The diagnosis of tuberculosis (TB) in children is difficult because of the low sensitivity and specificity of traditional microbiology techniques in this age group. Whereas in adults the culture of Mycobacterium tuberculosis (M. tuberculosis), the gold standard test, detects 80% of positive cases, it only detects around 30-40% of cases in children. The new methods based on the immune response to M. tuberculosis infection could be affected by many factors. It is necessary to evaluate the medical record, clinical features, presence of drug-resistant M. tuberculosis strains, comorbidities, and BCG vaccination history for the diagnosis in children. There is no ideal biomarker for all TB cases in children. A new strategy based on personalized diagnosis could be used to evaluate specific molecules produced by the host immune response and make therapeutic decisions in each child, thereby changing standard immunological signatures to personalized signatures in TB. In this way, immune diagnosis, prognosis, and the use of potential immunomodulators as adjunct TB treatments will meet personalized treatment.

Dysbiosis in Pediatrics Is Associated with Respiratory Infections: Is There a Place for Bacterial-Derived Products?

Respiratory tract infections (RTIs) are common in childhood because of the physiologic immaturity of the immune system, a microbial community under development in addition to other genetic, physiological, environmental and social factors. RTIs tend to recur and severe lower viral RTIs in early childhood are not uncommon and are associated with increased risk of respiratory disorders later in life, including recurrent wheezing and asthma. Therefore, a better understanding of the main players and mechanisms involved in respiratory morbidity is necessary for a prompt and improved care as well as for primary prevention. The inter-talks between human immune components and microbiota as well as their main functions have been recently unraveled; nevertheless, more is still to be discovered or understood in the above medical conditions. The aim of this review paper is to provide the most up-to-date overview on dysbiosis in pre-school children and its association with RTIs and their complications. The potential role of non-harmful bacterial-derived products, according to the old hygiene hypothesis and the most recent trained-innate immunity concept, will be discussed together with the need of proof-of-concept studies and larger clinical trials with immunological and microbiological endpoints.

Silence of the Lambs: The Immunological and Molecular Mechanisms of COVID-19 in Children in Comparison with Adults

Children infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can suffer from severe coronavirus disease 2019 (COVID-19). However, compared to adults and the elderly, susceptibility to SARS-CoV-2 infection in children seems to be lower; when infection does develop, most infected children remain asymptomatic or develop a mild disease. Understanding why children seem generally protected from severe COVID-19 and only rarely develop clinical conditions that can cause hospitalization, admission to the pediatric intensive care unit and death can be important. More details on the mechanism of action of SARS-CoV-2 could be defined. Moreover, the role played by children in virus diffusion should be better analyzed, and the development of effective preventive and therapeutic measures against COVID-19 could be favored. The main aim of this paper is to discuss the present knowledge on immunological and molecular mechanisms that could explain differences in COVID-19 clinical manifestations between children and adults. Literature analysis showed that although most children are clearly protected from the development of severe COVID-19, the reasons for this peculiarity are not fully understood. Developmental variations in immune system function together with the potential role of repeated antigen stimulation in the first periods of life on innate immunity are widely studied. As the few children who develop the most severe form of pediatric COVID-19 have certain alterations in the immune system response to SARS-CoV-2 infection, studies about the relationships between SARS-CoV-2 and the immune system of the host are essential to understand the reasons for the age-related differences in the severity of COVID-19.

Distinct Antiviral Properties of Two Different Bacterial Lysates

Oral bacterial lysates (OBLs) can reduce the frequency and severity of recurrent respiratory tract infections in children from viral and bacterial origins. OBL-induced early innate immune reaction was already shown, but the specific features of different OBLs have never been studied and compared. A study was conducted to assess in vitro the protective effects on rhinovirus- (RV-) infected human bronchial epithelial cells (BECs) of two slightly different OBLs: OM-85 and Pulmonarom. Furthermore, since immune cells represent the key arm for antiviral defence, the capacity of these OBLs to induce selected cytokine production in mouse bone marrow-derived DCs (BMDCs) was also evaluated. Although different OBLs may share some mechanisms to protect host cells from virus infection, some product-specific antimicrobial activities were observed on RV-infected human BECs and mouse BMDCs. These results are consistent with a product-specific response possibly triggered by different pathogen-associated molecular patterns (PAMPs) contained in OBLs.

Prevention of New Respiratory Episodes in Children with Recurrent Respiratory Infections: An Expert Consensus Statement

In healthy infants and young children, the development of respiratory tract infections (RTIs) is extremely common. In this paper, we present an international consensus of the available approaches for the prevention of recurrent RTIs in children, including the atopic/allergic ones as well as those with asthma. Few convincing measures for reducing the frequency and clinical relevance of recurrent respiratory episodes in RTI-prone children have been developed until now. Among the most recently suggested measures, immunotherapy is attractive, but only for OM-85 is there a sufficient number of well-conducted clinical trials confirming efficacy in RTIs prevention with an adequate safety profile. In the case of probiotics, it is not clear which bacteria can offer the best results and which dosage and schedule of administration are the most effective. The problems of dosage and the schedule of administration are not solved also for vitamin D, despite some promising efficacy results. While we wait for new knowledge, the elimination or reduction as much as possible of the environmental factors that favor RTIs, vaccination when available and/or indicated, and the systematic application of the traditional methods for infection prevention, such as hand washing, remain the best measures to prevent recurrent infections in RTI-prone children.

[The efficacy of OM85-BV in the treatment of recurrent upper respiratory tract infection with adenoid hypertrophy and the preliminary exploration of potential therapeutic mechanism]

Objective:To observe the efficacy of OM85-BV in the treatment of recurrent upper respiratory tract infection with adenoid hypertrophy and to explore its possible mechanism. Method:Four hundred and forty-eight children with recurrent upper respiratory tract infection and adenoid hypertrophy were collected. Three hundred and twenty-six patients in the control group were treated with conventional drugs, and one hundred and twenty-two patients in the observation group were treated with OM85-BV+conventional drugs, and the treatment lasted 12 weeks. The sleep obstructive symptoms of adenoid hypertrophy were scored according to OSA-18 before and after the treatment respectively（0, 6, 12 weeks）. The symptoms scores and effective rate of treatment between the study and the control group were compared. The patients in the control group and the observation group who were unresponsive to drug treatment received surgery after 12 weeks of drug treatment. The levels of serum IL-2, IL-4, IL-6, IL-10, TNF, IFN-γ and IgE, the ratio of serum CD3, CD4, CD8 in lymphocytes and the ratio of CD4/CD8 were compared between the study and the control group before operation. The levels of HBD-2, IFN-γ, IL-4, IL-6 cytokines in the adenoid were compared between the control group and the observation group. The expression and distribution of adenoid HBD-2, IFN-γ, IL-4, IL-6 were compared between the control group and the observation group. Result:After 12 weeks of treatment, the total effective rate of the observation group was significantly higher than that of the control group, and the improvement of sleep respiratory obstruction symptoms of children with recurrent upper respiratory tract infection and adenoid hypertrophy was also much better than that of the control group. The serum IFN-γ of the observation group was significantly higher than that of the control group, and there was no significant difference in serum IL-2, IL-4, IL-6, IL-10, TNF, IgE between the observation group and the control group. There was no significant difference in serum CD3, CD4, CD8 and CD4/CD8 between the observation group and the control group. In the observation group, the adenoid HBD-2 was significantly higher but IL-4, IFN-γ were significantly lower than that in the control group, and IL-6 had no significant difference compared with the control group. Conclusion:OM85-BV can significantly improve the sleep apnea symptoms but can not rise the level of immune lymphocytes in children with adenoid hypertrophy and recurrent upper respiratory tract infection.OM85-BV can improve the Th1 immune response, enhancing the ability of human body to fight against pathogens and induce the release of HBD-2, increasing the resistance to microorganisms, reducing the bacteria aggregation, weakening the local inflammatory response in adenoids.

Paediatric Recurrent Ear, Nose and Throat Infections and Complications: Can We Do More?

Recurrent respiratory tract infections (rRTIs), of which there are three main groups-otitis media, tonsillitis and sinusopathies-are very common in paediatric populations and are associated with significant morbidity and mortality due to complications. These infections substantially reduce quality of life for paediatric patients and their families and are a significant personal, medical and economic burden on the patients, the patients' families and the healthcare system. Most rRTIs are of viral origin; however, indiscriminate use of antibiotics in their treatment has led to development of bacterial resistance. Effective management of rRTIs to reduce the burden of disease and to avoid overuse of antibiotics has become a great therapeutic challenge. New strategies for the management of paediatric rRTIs include focus on prevention using non-specific immunomodulators to boost the body's natural defences against infection and to downregulate infection- and allergen-induced airway inflammation. The oral immunomodulator, OM-85, a bacterial lysate, acts on the innate and adaptive branches of the immune system, conferring protection against viral and bacterial infections, and controls inflammation, thereby reducing tissue damage. OM-85 has demonstrated good tolerability and clinical efficacy in reducing the number and duration of RTIs in children with recurrent airway infections. It has also been reported to reduce the use of concomitant medications, including antibiotics, time to cure and school absenteeism. OM-85 is efficacious and well tolerated when administered concomitantly with inactivated influenza vaccine (IIV) and has been shown to reduce wheezing attacks induced by RTI in young children. Clinical results show that the greater the risk of rRTIs, the greater the benefit with OM-85. OM-85 may be considered a promising tool to add to the limited armamentarium of the ear, nose and throat (ENT) physician dealing with rRTIs and their complications, such as recurrent wheeze and asthma inception.

Polymorphism of proinflammatory cytokine genes in girls predisposed to recurrent respiratory infections

Acute respiratory infections (ARI) are very common in children and often prompt parents to seek medical advice. Increased susceptibility to ARI is caused by a number of factors, including genetically determined imbalances in cytokine production. The aim of this study was to analyze the frequency of 6 clinically relevant polymorphisms of proinflammatory cytokine genes in girls predisposed to recurrent respiratory infections. The study was conducted in girls aged 7–17 years who were undergoing a routine medical checkup. A group of children with frequent respiratory infections was identified. The following polymorphisms were analyzed for possible associations with predisposition to frequent respiratory infections: IL1β T-31C (rs1143627), IL1β T-511C (rs16944), IL1β C-3953T (rs1143634), IL1β G-1473C (rs1143623); IL6 C-174G (rs1800795), and TNFα G-308A (rs1800629). For polymorphism detection, PCR and gel electrophoresis were used. The following alleles were found to be associated with an increased risk for recurrent respiratory infections in girls aged 7–17 years: С-31 (rs1143627) (OR = 2.05; CI: 1.16–3.64; р = 0.013) and С-511 (rs16944) (OR = 3.11; CI: 1.25–7.76; р = 0.013) of the IL-1β gene.