Clinical epidemiology of adenovirus pneumonia among Chinese hospitalized children

Clinical features and risk factors of adenovirus-related plastic bronchitis in children

BACKGROUND

To analyze the clinical characteristics of children with adenoviral pneumonia, identify independent risk factors for early prediction of plastic bronchiolitis (PB), and develop a predictive nomogram.

METHODS

This retrospective study analyzed the clinical data of children diagnosed with adenoviral pneumonia. Patients were categorized into PB and non-PB groups. General characteristics, clinical symptoms, laboratory findings, and imaging results were compared between the two groups. Multivariate logistic regression was used to identify significant risk factors, and a nomogram model was constructed.

RESULTS

Among the 164 patients, 139 were in the non-PB group and 25 were in the PB group. Multivariate logistic regression identified diminished breath sounds, D-dimer (D-D) levels, and Lactic dehydrogenase (LDH) levels as significant risk factors for PB. The nomogram developed from these factors had an area under the receiver operating characteristic curve (AUC) of 0.904 (95% confidence interval: 0.847-0.960). The Hosmer-Lemeshow test showed good calibration (p = 0.515, X2 = 7.207).

CONCLUSIONS

Diminished breath sounds, D-D levels, and LDH levels are independent risk factors for PB in children with adenoviral pneumonia. The developed nomogram demonstrates high predictive accuracy and good calibration, providing a valuable tool for early prediction and clinical decision-making. Future studies should validate this nomogram in larger and diverse populations.

Increased circulation of adenovirus in China during 2023-2024: Association with an increased prevalence of species B and school-associated transmission

OBJECTIVES

We report on the surge in human adenovirus (HAdV) cases in China starting in October 2023 and analyze the key drivers behind this increased circulation in the post-COVID-19 period.

METHODS

We analyzed targeted next-generation sequencing (tNGS) data from 1,875,862 hospitalized acute respiratory infection (ARI) cases across 4758 hospitals in 314 cities throughout all 31 provinces of mainland China. An in-house script was used to analyze the positivity rates of different HAdV species nationwide and across various provinces. We also assessed the age-specific infection risk for HAdV species B and C using restricted cubic splines (RCS), and we tested differences in HAdV infection rates between vacation periods and school terms using the Kruskal-Wallis test.

RESULTS

We identified an increased prevalence of HAdV species B replacing circulating species C, and this increase was associated with elevated HAdV activity in China from October 2023 to August 2024. Age-specific analysis indicates that, compared to HAdV species C, HAdV species B has a higher infection rate in school-aged children. Comparison of HAdV incidence rates during school terms and vacations showed that schools are the primary transmission setting for HAdV species B. These findings strongly support the conclusion that school-associated cluster infections caused by HAdV species B are the drivers of the ongoing increased circulation of HAdV in China.

CONCLUSION

This study found that changes in susceptible populations and transmission settings due to an increased prevalence of HAdV species B were the key factors driving the elevated HAdV activity in China starting in October 2023.

Clinical epidemiological characteristics of hospitalized pediatric viral community-acquired pneumonia in China

BACKGROUND

Community acquired pneumonia (CAP) is a major global public health concern among children, with viral pathogens playing a significant role. Despite this, national multicenter studies on viral community acquired pneumonia (VCAP) in hospitalized children remain scarce. The study employed a multicenter approach to investigate the clinical epidemiology and burden of VCAP in hospitalized children across China.

METHOD

Data were extracted from the face sheets of discharge medical records (FSMRs) within the FuTang Update Medical Records (FUTURE) database, spanning 2016 to 2022. VCAP cases from 33 tertiary children's hospitals were identified and analyzed. Epidemiological characteristics, length of stay (LOS), and hospitalization costs were compared using appropriate statistical methods.

RESULTS

Between January 2016 to December 2022, 72,905 hospitalized cases of CAP with confirmed diagnoses of viral pathogens were documented, accounting 4.07% of all CAP cases (72,905/1791,343). Respiratory syncytial virus (RSV) was the leading cause, responsible for 57.21% of cases, followed by adenovirus, parainfluenza virus, human rhinovirus and influenza virus. The male-to-female ratio was 1.69:1, and infants under 1 year of age represented 59.84% of hospitalizations. Temporal trends showed an increase in VCAP hospitalizations from 2016 to 2019, a decline in 2020, followed by a resurgence in 2021 and 2022. Seasonally, the majority of cases occurred during winter (December to February, 41.67%), while summer (June to August) had the lowest proportion (16.80%). A total of 40 deaths were reported, representing a mortality rate of 0.05%. The median LOS was 7 days, with a median hospitalization cost of 907.38 USD.

CONCLUSIONS

Although the proportion of CAP cases in children with confirmed viral pathogen in China is relatively low, VCAP remains a significant health burden for children. RSV is the most prevalent viral cause of VCAP, particularly affecting infants under 1 year of age, while adenovirus is associated with the highest mortality, longest LOS, and highest hospitalization costs. VCAP cases peak during the winter months. While the prognosis is generally favorable, the disease continues to pose a considerable public health challenge.

Risk factor analysis and prediction model construction for severe adenovirus pneumonia in children

BACKGROUND

Severe adenovirus pneumonia in children has a high mortality rate, but research on risk prediction models is lacking. Such models are essential as they allow individualized predictions and assess whether children will likely progress to severe disease.

METHODS

A retrospective analysis was performed on children with adenovirus pneumonia who were hospitalized at the Children's Hospital of Nanjing Medical University from January 2017 to March 2024. The patients were grouped according to clinical factors, and the groups were compared using Ridge regression and multiple logistic regression to identify risk factors associated with severe adenovirus pneumonia. A prediction model was constructed, and its value in clinical application was evaluated.

RESULTS

699 patients were included in the study, with 284 in the severe group and 415 in the general group. Through the screening of 44 variables, the final risk factors for severe adenovirus pneumonia in children as the levels of neutrophils (OR = 1.086, 95% CI: 1.054‒1.119, P < 0.001), D-dimer (OR = 1.005, 95% CI: 1.003‒1.007, P < 0.001), fibrinogen degradation products (OR = 1.341, 95% CI: 1.034‒1.738, P = 0.027), B cells (OR = 1.076, 95%CI: 1.046‒1.107, P < 0.001), and lactate dehydrogenase (OR = 1.008, 95% CI: 1.005‒1.011, P < 0.001). The value of the area under the receiver operating characteristic curve was 0.974, the 95% CI was 0.963-0.985, and the P-value of the Hosmer-Lemeshow test was 0.547 (P > 0.05), indicating that the model had strong predictive power.

CONCLUSION

In this study, the clinical variables of children with adenovirus pneumonia were retrospectively analyzed to identify risk factors for severe disease. A prediction model for severe disease was constructed and evaluated, showing good application value.

Activation of the NLRP3 inflammasome by human adenovirus type 7 L4 100-kilodalton protein

Human adenovirus type 7 (HAdV-7) is a significant viral pathogen that causes respiratory infections in children. Currently, there are no specific antiviral drugs or vaccines for children targeting HAdV-7, and the mechanisms of its pathogenesis remain unclear. The NLRP3 inflammasome-driven inflammatory cascade plays a crucial role in the host's antiviral immunity. Our previous study demonstrated that HAdV-7 infection activates the NLRP3 inflammasome. Building upon this finding, our current study has identified the L4 100 kDa protein encoded by HAdV-7 as the primary viral component responsible for NLRP3 inflammasome activation. By utilizing techniques such as co-immunoprecipitation, we have confirmed that the 100 kDa protein interacts with the NLRP3 protein and facilitates the assembly of the NLRP3 inflammasome by binding specifically to the NACHT and LRR domains of NLRP3. These insights offer a deeper understanding of HAdV-7 pathogenesis and contribute to the development of novel antiviral therapies.