Background: The COVID‐19 pandemic have impacts on the prevalence of other [pathogen](javascript:;)s and people’s social lifestyle. This study aimed to compare the [pathogen](javascript:;), allergen and micronutrient characteristics of pediatric inpatients with pneumonia prior to and during the COVID-19 pandemic in a large tertiary hospital in Shanghai, China. Methods: Patients with pneumonia admitted to the Department of Pediatric Pulmonology of Xinhua Hospital between March-August 2019 and March-August 2020 were recruited. And clinical characteristics of the patients in 2019 were compared with those in 2020. Results: Hospitalizations for pneumonia decreased by 74% after the COVID-19 pandemic. For [pathogen](javascript:;)s, virus, mycoplasma pneumoniae (MP) and mixed infection rates were all much lower in 2020 than those in 2019 ( P < 0.01). Regarding allergens, compared with 2019, the positive rates of house dust mite, shrimp and crab were significantly higher in 2020 ( P < 0.01). And for micronutrients, the levels of vitamin B2, B6, C and 25-hydroxyvitamin D (25(OH)D) in 2020 were observed to be significantly lower than those in 2019 ( P < 0.05). For all the study participants, longer hospital stay (OR = 1.521, P = 0.000), milk allergy (OR = 6.552, P = 0.033) and [calcium](javascript:;) (Ca) insufficiency (OR = 12.048, P = 0.019) were identified as high-risk factors for severe pneumonia by multivariate analysis. Conclusions: The number of children hospitalized with pneumonia and incidence of common pathogen infections were both reduced, and that allergy and micronutrient status in children were also changed after the outbreak of the COVID-19 pandemic.

Background Perfluorooctanoic acid (PFOA) is widely used in daily life, however, research has shown its immune suppression function. Our aim is to investigate the relationship between prenatal exposure to PFOA and allergic diseases in children. Methods A prospective birth cohort study involving 648 pregnant women was conducted. Prenatal information was collected by an interview with the women and from medical records. Fetal umbilical cord blood was collected, and concentration of PFOA and genotype of IL-13 rs20541 were detected. Children were followed at 6, 12 and 24 months and information on the development of allergic diseases was recorded. Multivariate logistic regression analysis was used to examine the association between PFOA and allergic diseases. Stratified analysis was performed based on gender and genotype of IL-13 rs20541. Results In multivariate adjusted models, the highest PFOA quartile is associated with odds of atopic dermatitis (AD) (OR 1.66, 95% CI 1.09-2.55), wheezing (OR 4.06, 95% CI 1.30-12.68), and allergic diseases (OR 1.71, 95% CI 1.15-2.54). Female patients with the highest PFOA quartile have a higher odd of AD (OR 2.25, 95% CI 1.20-4.23) and allergic diseases (OR 1.93, 95% CI 1.07-3.46). Patients with GG genotype of IL-13 rs20541 and the highest PFOA quartile also have a higher odd of AD (OR 2.82, 95% CI 1.41-5.67), wheezing (OR 15.16, 95% CI 1.38-166.59), and allergic diseases (OR 2.42, 95% CI 1.27-4.61). Conclusions Prenatal exposure to PFOA increases the risk of developing allergic diseases in children, especially for the female patients and those with the genotype of IL-13 rs20541 GG.

Background：Wheezing is an important respiratory symptom in the diagnosis of asthma. However, wheezing is common in children and often related to viral infection. This and the lack of reliable biological indicators for asthma create difficulty in diagnosing asthma early in children. Objective: In this study, the levels of CD4+CCR6+CRTh2+ memory Th2 cells in wheezing children with different diagnostic outcomes were investigated to determine correlation with a diagnosis of asthma and to assess their potential clinical value as a biological indicator for this disease. Methods: A prospective study was performed with a cohort of wheezing children aged 3 months to 6 years hospitalized in the Division of Pulmonary Pediatrics at Shanghai Xinhua hospital and Shanghai children’s medical center affiliated to Shanghai Jiao Tong University School of Medicine from July 2017 to March 2018. After inclusion, the level of serum IgE, presence of allergen-specific serum IgE (sIgE) and proportion of circulating CD4+CCR6+CRTh2+ memory Th2 cells were counted. In addition, the patients’ personal and family histories of allergic disease were acquired by questionnaire. The children were followed up annually over 2 years by telephone call with a guardian to record whether the child had been diagnosed with asthma. The accuracy of an increased proportion of CD4+CCR6+CRTh2+ memory Th2 cells as an indicator of asthma was assessed. Results: A total of 43 children completed follow-up. The median of circulating CD4+CCR6+CRTh2+ memory Th2 cells in wheezing children diagnosed with or without asthma was 1.2%(0.8%~2.9%) and 0.6%(0.1%~0.9%), respectively, and was significantly higher in children diagnosed with asthma (P<0.01). The median of circulating CD4+CCR6+CRTh2+ memory Th2 cells in atopic children was also significantly higher in children diagnosed with asthma than in children without asthma, at 1.3%(0.8%~2.9%) and 0.6%(0.3%~1.0%), respectively, (P<0.01). Furthermore, the level of serum IgE was significantly higher in children with asthma (P<0.05). Logistic regression analysis indicated that the level of circulating CD4+CCR6+CRTh2+ memory Th2 cells were independent risk factors for asthma. The area under the receiver operating characteristic curve (ROC) was 0.922. There was no significant difference in the positive rate of memory Th2 cells in the context of allergic rhinitis (AR) or atopic dermatitis (AD) (P>0.05). Conclusion: Our exploratory study found that an increase in the level of circulating CD4+CCR6+CRTh2+ memory Th2 cells could be used as a biological indicator for early diagnosis of asthma, especially in predicting the risk of asthma in atopic children.