Asthma is one of the common chronic respiratory diseases in children, which poses a serious threat to children's quality of life. Respiratory infection is a risk factor for asthma. Compared with healthy children, children with early respiratory infections have a higher risk of asthma and an increased chance of developing severe asthma. Many clinical studies have confirmed the correlation between respiratory infections and the pathogenesis of asthma, but the underlying mechanism is still unclear. The gut microbiome is an important part of maintaining the body's immune homeostasis. The imbalance of the gut microbiome can affect the lung immune function, and then affect lung health and cause respiratory diseases. A large number of evidence supports that there is a bidirectional regulation between intestinal flora and respiratory tract infection, and both are significantly related to the development of asthma. The changes of intestinal microbial components and their metabolites in respiratory tract infection may affect the occurrence and development of asthma through the immune pathway. By summarizing the latest advancements in research, this review aims to elucidate the intricate connection between respiratory tract infections and the progression of asthma by highlighting its bridging role of the gut microbiome. Furthermore, it offers novel perspectives and ideas for future investigations into the mechanisms that underlie the relationship between respiratory tract infections and asthma.

To describe the epidemiological, clinical, and household transmission characteristics of pediatric COVID-19 cases in Shanghai, China. Pediatric patients with COVID-19 hospitalized in Shanghai from March-May 2022 were enrolled in this retrospective, multicenter cohort study. The symptoms and the risk factors associated with disease severity were analyzed. In total, 2620 cases (age range, 24 days-17 years) were enrolled in this study. Of these, 1011 (38.6%) were asymptomatic, whereas 1415 (54.0%), 190 (7.3%), and 4 (0.2%) patients developed mild, moderate, and severe illnesses, respectively. Household infection rate was negatively correlated with household vaccination coverage. Children aged 0-3 years, those who are unvaccinated, those with underlying diseases, and overweight/obese children had a higher risk of developing moderate to severe disease than children aged 12-17 years, those who were vaccinated, those without any underlying disease, and those with normal weight, respectively (all P <0.05). A prolonged duration of viral shedding was associated with disease severity, presence of underlying diseases, vaccination status, and younger age (all P <0.05). Children aged younger than 3 years who were not eligible for vaccination had a high risk of developing moderate to severe COVID-19 with a prolonged duration of viral shedding. Vaccination could protect children from COVID-19 at the household level.

Obesity is an important risk factor and common comorbidity of childhood asthma. Simultaneously, obesity-related asthma, a distinct asthma phenotype, has attracted significant attention owing to its association with more severe clinical manifestations, poorer disease control, and reduced quality of life. The establishment of the gut microbiota during early life is essential for maintaining metabolic balance and fostering the development of the immune system in children. Microbial dysbiosis influences host lipid metabolism, triggers chronic low-grade inflammation, and affects immune responses. It is intimately linked to the susceptibility to childhood obesity and asthma and plays a potentially crucial transitional role in the progression of obesity-related asthma. This review article summarizes the latest research on the interplay between asthma and obesity, with a particular focus on the mediating role of gut microbiota in the pathogenesis of obesity-related asthma. This study aims to provide valuable insight to enhance our understanding of this condition and offer preliminary evidence to support the development of therapeutic interventions.

The association between viral infections and asthma has garnered significant attention in recent years. Accumulating evidence suggests that viral infections can trigger asthma exacerbations, while asthma may also influence the susceptibility to viral infections, thereby creating a cycle of worsening symptoms and recurrent asthma attacks. Given that asthma is predominantly driven by Type 2 immune responses and viral infections are typically associated with Type 1 immune responses, the innate immune cells and cytokines that participate in both conditions appear to be the critical bridge connecting these two processes. In particular, innate immune cells play a pivotal role in modulating the immune response at the interface of viral infections and asthma. In this review, we summarize the key innate immune cells and cytokines involved in viral infections and asthma, highlighting their immunoregulatory mechanisms. We aim to provide novel perspectives and potential therapeutic directions for the clinical management of recurrent asthma attacks induced by viral infections.

Background: Childhood and adolescent obesity has become a major public health concern, contributing to the increasing burden of asthma. However, the global and regional trends of asthma attributable to high BMI in this population remain unclear. This study aimed to assess the burden of asthma due to high BMI among children and adolescents from 1990 to 2021, exploring disparities across different sex groups and Socio-Demographic Index (SDI) regions and projecting future trends. Methods: Data were extracted from the Global Burden of Disease (GBD) 2021 database. The analysis in this study covers the following indicators: age-standardized mortality rate (ASMR), age-standardized disability-adjusted life year rate (ASDR), years lived with disability (YLDs), years of life lost (YLLs), as well as crude mortality rate, crude disability-adjusted life year rate, and their respective percentage change (PC) and estimated annual percentage change (EAPC) from 1990 to 2021. Inequality in disease burden across SDI regions was quantified using the Slope Index of Inequality (SII) and Concentration Index (CI). Future burden projections were conducted using the Autoregressive Integrated Moving Average (ARIMA) model. The percentage of DALYs attributable to risk factors is reported among all age groups and individuals under 20 years. Results: From 1990 to 2021, globally, the mortality rates and numbers of asthma cases caused by high body mass index (BMI) decreased, while the numbers and rates of disability-adjusted life years (DALYs) increased. The number and rate of DALY showed different trends in SDI regions and sex groups. Statistical analysis showed a significant correlation between SDI and asthma burden ( P < 0.001), with the overall disease burden increasing as SDI rose. However, this trend was not entirely consistent, as country variations were observed. Otherwise the higher the SDI, the lower the age-standardized mortality rate of asthma usually is. Future projections show that without effective intervention measures, the absolute burden will continue to increase. Conclusion: Despite regional differences, the global burden of asthma attributable to high BMI among children and adolescents remains substantial, with notable disparities across SDI regions. Given the projected increase in burden, urgent public health strategies targeting childhood obesity prevention and early intervention are essential to mitigate the long-term respiratory health consequences.