Objective: To investigate whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection increases the adverse reactions of subcutaneous specific immunotherapy in children. Methods: This study was conducted by collecting relevant data from children who underwent house dust mite SCIT from April 3, 2021 to March 18, 2023, including information on the time of COVID-19 infection, symptoms, and adverse reactions after each allergen injection. A mixed-effects model was used to analyze the changes in adverse reactions before and after COVID-19 infection. Results: Among the records of adverse reactions from 2658 injections in 123 children who underwent SCIT, the overall adverse reaction rate before COVID-19 infection was 39.8% and 30.0% after COVID-19 infection. Compared with pre-infection with COVID-19, the risks of overall adverse reactions, local adverse reactions, and systemic adverse reactions of desensitization treatment after COVID-19 infection were reduced (OR = 0.24, 0.31, and 0.28, all P <0.05). Among the local adverse reactions, the incidence of the unvaccinated group was the highest (15.3% vs. 7.1%). The incidence of overall and local adverse reactions to SCIT decreased in 2-vaccinated COVID-19 recipients (OR = 0.29–0.31, P <0.05) Conclusions: SARS-CoV-2 infection does not increase the incidence of adverse reactions to SCIT in children. SCIT can be performed according to the course of treatment after the SARS-CoV-2 infection is controlled, just like with other common infectious diseases.

Background: Mycoplasma pneumoniae pneumonia (MPP) is often complicated with co-infections that worsen the prognosis, but the outcomes in pediatric cases are unclear. The aim of this study is to investigate the association of co-infection and outcomes in severe MPP that occurs in childhood. Methods: This retrospective study included 184 pediatric cases of severe MPP that were managed at our hospital (between January 2014 and December 2017). The cohort was divided into the single Mycoplasma pneumoniae infection, co-infection with a noxa other than M. pneumoniae, and co-infection with two or more noxae other than M. pneumoniae groups. The demographic and clinical information of the patients was compared via statistical analysis. Results: The incidence of co-infections was high at 64.1%. Cytomegalovirus and Epstein-Barr virus were the most common causes of co-infection. According to the findings of binary logistic regression analysis, the presence of more than one pathogen (other than M. pneumoniae) was positively associated with the score determined from Pediatric Risk of Mortality III (β = 0.760, odds ratio [OR] = 2.139, 95% confidence interval [CI] = 1.391–2.390, P = 0.001), Pediatric Critical Illness Score (β = 1.203, OR = 3.328, 95% CI = 1.723–6.731, P = 0.000), and total length of hospital stay (β = 0.730, OR = 2.075, 95% CI = 1.404–3.066, P = 0.000). Conclusion: Viral and bacterial co-infection in pediatric cases of severe MPP is positively associated with hospitalization period and disease severity, and ultimately, may increase the chances of severe illness and death among children.

Background: Acute myeloid leukemia (AML) and hyperleukocytosis are related to an unfavorable prognosis. The impact of hyperleukocytosis on the prognosis of pediatric AML has not been fully explained so far. We aimed to assess the clinical characteristics and prognosis of pediatric AML with hyperleukocytosis, referred to as white blood cell (WBC) count ≥50×109/L. Methods: A total of 307 newly diagnosed non-acute promyelocytic leukemia patients were continuously enrolled at our center from October 2005 to September 2015. 81 patients with initial leukocyte counts ≥50×109/L. The baseline demographic and clinical characteristics of AML patients were compared. Progression-free survival (PFS) and overall survival (OS) were documented. Results: Hyperleukocytosis occurred in 26.38% of AML patients, and FAB M5 subtype (n=41, 50.62%) and FLT3-ITD mutations (n=16, 19.75%) had a high proportion in AML and hyperleukocytosis. Overall mortality was significantly higher in patients with hyperleukocytosis than patients without hyperleukocytosis (50.62% vs. 35.84%, P=.020). Patients with hyperleukocytosis had a lower 10-year PFS and OS rates than those without hyperleukocytosis (44.4%±9.4% vs. 59.7%±5.5%, P=.041; 49.4%±9.4% vs. 64.2%±5.4%, P=.051, respectively). There were similar PFS and OS rates between the subgroups of patients with WBC count 50-100×109/L and WBC count ≥100×109/L (43.8%±13.3% vs. 44.9%±12.3%, P=.507; 46.9%±13.3% vs. 51.0%±12.3%, P=.907, respectively). In all patients with hyperleukocytosis, male and FAB M5 subtype patients had a significantly inferior survival, while CBF-AML had a better survival. Conclusions: A WBC count greater than 50×109/L at onset was a critical predictive adverse factor in pediatric AML.