BACKGROUND:Mycoplasma pneumoniae pneumonia (MPP) is a leading cause of community-acquired pneumonia in children. The COVID-19 pandemic substantially disrupted the transmission dynamics of M. pneumoniae, yet large-scale, nationwide data characterizing the clinical and epidemiological evolution of pediatric MPP in China across the pandemic period remain scarce. METHODS:We analyzed 325,781 MPP hospitalizations from 31 tertiary children's hospitals across mainland China between 2016 and 2023, using the FUTURE Database. Temporal trends and demographic differences in disease severity, co-infections, complications, length of stay (LOS), and hospitalization costs were systematically evaluated. RESULTS:MPP admissions peaked in 2023, accounting for 8.76% of all pediatric hospitalizations. The male-to-female ratio was 1.15:1. children aged 3-6 years accounted for the largest proportion (32.42%), though children aged 6-10 years became predominant in 2023. Severe MPP increased significantly over time (P for trend <0.0001), rising from 3.78% in 2017 to above 13% after 2020. Viral and bacterial co-infection rates rose significantly to 24.13% and 10.09% in 2023, with infants bearing the highest burden. Respiratory complications increased over time to over 10% after 2021, while extrapulmonary complications declined. The median LOS was 7 days (IQR 5-9), and the median cost was 5891.61CNY (IQR 4427.86-8425.95), both decreased significantly from 2016 to 2023. Severe MPP and coinfections were associated with longer LOS and higher costs. CONCLUSIONS:This nationwide multicenter study reveals a post-pandemic surge in pediatric MPP in China, with rising severity, a shift towards school-aged children, and increasing co-infection rates. Despite improved healthcare efficiency, growing clinical complexity demands enhanced surveillance, risk stratification, and public health preparedness.

BACKGROUND:The COVID-19 pandemic has affected the epidemiology of Mycoplasma pneumoniae pneumonia (MPP). This study aimed to provide a comprehensive overview of research trends, challenges, and advancements in pediatric MPP, particularly in the post-COVID-19 era. METHODS:A bibliometric analysis of pediatric MPP literature (1992-2025) from the Web of Science was conducted using VOSviewer and CiteSpace. RESULTS:A total of 2357 relevant articles were published by 11,318 authors from 2714 institutions across 94 countries. Publications increased significantly during and after the COVID-19 pandemic. China and the United States were the most influential countries, while Soochow University and Capital Medical University were the most active institutions. The top 10 co-cited references included four research articles and six review articles. Over the past 34 years, the research focus has shifted from community-acquired pneumonia (CAP) and pediatric pulmonary diseases to MPP. Current research hotspots include epidemiology, diagnostics, macrolide resistance, refractory MPP, and co-infections, with recent citation bursts related to COVID-19. CONCLUSION:This bibliometric analysis provides a systematic overview of pediatric MPP research from the 1990s to the post-COVID-19 era. It highlights the need for stronger global collaboration and further epidemiological studies to address MPP-related challenges, especially amid evolving infectious threats like COVID-19. IMPACT:This study offers a comprehensive overview of pediatric Mycoplasma pneumoniae pneumonia (MPP) research from 1992 to 2025, revealing critical changes and advances in the field. Detailed analyses of core contributors, thematic evolution, research hotspots and frontiers advance the overall understanding of pediatric MPP. The findings reveal persistent challenges in epidemiology, diagnostics, macrolide resistance, refractory MPP, and co-infections. This study highlights the necessity of strengthening global collaboration and conducting continuous epidemiological surveillance on MPP amid emerging infectious threats such as COVID-19. These results provide valuable insights for addressing clinical challenges and developing novel therapeutic strategies.

Background:Although randomized controlled trials (RCTs) have confirmed the mucolytic efficacy of ambroxol hydrochloride solution for inhalation (AHSI) in selected cohorts, their stringent exclusion criteria often omit children with comorbidities and complex presentations encountered in routine practice. Consequently, real-world evidence is needed to evaluate the effectiveness and safety of AHSI in a broader, clinically representative pediatric population with acute lower respiratory tract infections (ALRTIs). This study therefore aimed to assess the real-world effectiveness, safety, and nebulizer compatibility of a 7-day AHSI regimen added to standard care in a large, multicenter cohort of hospitalized pediatric patients with ALRTI. Methods:This real-world, multicenter, open-label, single-arm study enrolled hospitalized patients aged ≥6 months with ALRTI (acute bronchitis, bronchiolitis, or pneumonia) and symptom duration <7 days across 62 centers in China (April 2021-April 2022). Key inclusion criteria included a cough score ≥2 (0-4 scale), tenacious sputum, and difficulty expectorating. Major exclusions comprised severe pneumonia, bronchial asthma, interstitial lung disease, significant hepatic or renal dysfunction [alanine aminotransferase (ALT) >1.5× upper limit of normal (ULN), total bilirubin (TBil) or serum creatinine (Scr) > ULN], other severe comorbidities, known hypersensitivity to ambroxol, or recent trial participation. Participants received weight-based doses of nebulized AHSI twice daily for 7 days as add-on to standard care. Follow-up visits occurred at day 4 and day 7 (end of treatment). Primary endpoints were the cough improvement rate (defined by a reduction in cough score) and the overall clinical response rate (investigator-assessed improvement). Secondary endpoints included changes from baseline in cough, throat rales, and pulmonary auscultation scores. Safety assessments comprised monitoring of adverse events (AEs) (coded with MedDRA), vital signs, and laboratory tests (hematology, biochemistry, urinalysis) at baseline and day 7. Results:A total of 2,599 children were enrolled [full analysis set (FAS)]. At baseline, mean age was 3.60±2.50 years, 57.6% were male, and symptom scores were: cough 2.10±0.30, throat sputum 1.65±0.59, lung auscultation 1.44±0.70. In the FAS, the cough improvement rate was 96.73% [95% confidence interval (CI): 96.05-97.41] and the clinical response rate was 94.73% (95% CI: 93.87-95.59). All symptom scores decreased significantly from baseline to day 7 (P<0.001). Drug-related AEs (DRAEs) occurred in 0.39% of patients, predominantly mild-to-moderate rash, transient liver enzyme elevations, and gastrointestinal events; no serious DRAEs were reported. Outcomes were consistent across pneumonia and bronchitis subgroups and across various nebulizer types. Conclusions:This large real-world study demonstrated that a 7-day course of AHSI, added to standard care, was associated with clinically meaningful improvements in respiratory symptoms and a favorable safety profile in children with ALRTI. The consistent effects across disease subtypes and nebulizer devices underscore the practical utility of AHSI in diverse pediatric settings. While the single-arm design limits causal inference, these findings provide robust real-world evidence supporting AHSI as an effective expectorant option. Prospective confirmation through RCTs will further define its role in first-line therapy.

Objectives: To investigate the clinical and epidemiological characteristics of respiratory syncytial virus (RSV)-associated acute lower respiratory tract infection (ALRTI) among hospitalized children in the Baoding region of Hebei Province, China. Methods: The study subjects were inpatients diagnosed with ALRTI at a pediatric hospital in Baoding between 1 June 2017 and 31 December 2024. A retrospective analysis was conducted on the detection of RSV and other common respiratory viruses in respiratory specimens to evaluate the clinical epidemiological characteristics of RSV. Viral detection was performed using immunofluorescence (IF) or polymerase chain reaction (PCR) assays. Results: The overall RSV detection rate was 16.8% (4945/29,399), with 6.7% co-infections. The RSV detection rate was 29.8% (2604/8729) in infants younger than 1 year and 18% (942/5232) in the 1-year-old group, then showing a decreasing trend with increasing age, with the lowest rate of 3.8% (283/7366) observed in the ≥5 years age group. The RSV detection rate decreased from 19.9% before the COVID-19 pandemic (2017-2019) to around 13% during and after the pandemic (χ2 = 233.732, p < 0.001), accompanied by a drop in the proportion of children under 2 years from 78.5-79.6% before the COVID-19 pandemic to 42.1-51.1% after the pandemic period (χ2 = 387.565, p < 0.001). RSV seasonality shifted from a typical single winter-spring peak in the pre-COVID-19 era to a markedly reduced peak during the pandemic, in contrast to a delayed summer-autumn "off-season" pattern observed in the post-pandemic period. Conclusions: RSV remains the predominant pathogen for hospitalized ALRTI in Baoding, particularly among infants. Detection rates of RSV declined with increasing age. The COVID-19 pandemic has profoundly impacted RSV prevalence patterns and seasonality, underscoring the critical need for long-term surveillance.

Respiratory syncytial virus (RSV) remains the leading viral cause of severe lower respiratory tract infections in infants and young children worldwide, driving a substantial global disease burden. While monoclonal antibodies (mAbs) provide well-established passive protection against RSV, no comprehensive bibliometric analysis has yet characterized the full research landscape of this field.We retrieved 3,554 records from the Web of Science Core Collection and included 956 eligible articles for in-depth analysis using Bibliometrix, VOSviewer, and CiteSpace. Annual publications have surged sharply since 2021, peaking at 184 papers in 2025. The United States leads global output with 353 publications, and AstraZeneca ranks as the most productive institution.Research priorities have shifted from palivizumab prophylaxis for high-risk infants to nirsevimab for universal infant protection. Current key areas include preterm infant prevention, real-world nirsevimab evaluation, and maternal immunization strategies. Critically, low- and middle-income countries bear most global RSV mortality yet contribute minimal research and face steep access barriers, underscoring the urgent need for equitable global partnerships. What is Known RSV is the leading cause of severe lower respiratory tract infections in infants, and monoclonal antibodies confer robust passive protection against disease. No prior bibliometric analysis has systematically mapped the global research landscape or evolving priorities in this field. What is New This first comprehensive bibliometric analysis identifies a marked surge in research output post‑2021, alongside a paradigm shift from palivizumab to nirsevimab for universal protection. Preterm infants and nirsevimab have emerged as major front‑line research priorities. Low- and Middle-Income Countries bear the vast majority of global RSV mortality yet contribute disproportionately little research and face formidable access barriers, underscoring the critical need for global collaboration and technology transfer.

BackgroundYin Hu Gan Mao San (YHGMS) is a traditional Chinese herbal preparation derived from Yin Qiao San, used for topical application to treat wind-heat colds. This study aims to evaluate the clinical efficacy and safety of YHGMS in children with acute upper respiratory tract infection (AURTI) of wind-heat pattern.MethodsThis prospective, real-world cohort study enrolled 999 children with AURTI from 23 hospitals from May 2022 to June 2023. Participants were naturally divided into an exposed group (n = 671) that received YHGMS and a non-exposed group (n = 328) that did not receive YHGMS or any other traditional Chinese medicine. Propensity score matching was used to balance baseline characteristics. Primary outcomes included clinical recovery rate and time to recovery. Secondary outcomes included time to normal temperature, symptom resolution rates, and safety profile.ResultsAfter propensity score matching, the YHGMS group demonstrated significantly higher recovery rates on day 3 (52.64% vs. 36.09%), day 5 (81.00% vs. 68.81%), and day 7 (94.72% vs. 87.64%) (all P < 0.0001). Median recovery time (3.0 vs. 4.0 days) and time to normal temperature (1.0 vs. 2.0 days) were significantly shorter in the YHGMS group (both P < 0.0001). Resolution rates of individual symptoms were consistently higher in the YHGMS group. The incidence of adverse reactions was low (1.51%), comprising only mild, self-limiting local skin reactions.ConclusionYHGMS was associated with faster clinical recovery and symptom resolution in children with AURTI (wind-heat pattern), without significant safety concerns. As monotherapy, YHGMS showed better outcomes than chemical medicine alone; in combination, it also accelerated resolution of clinical symptoms and recovery.

Pediatric postinfectious bronchiolitis obliterans (PIBO) is a long-term sequela of severe lower respiratory tract infection. However, the underlying pathogenic mechanisms within the airways remain poorly understood. Bronchoalveolar lavage fluid (BALF) from six children with PIBO and three control children was subjected to transcriptomic, proteomics and untargeted metabolomics analyses. Integrated analysis identified key differentially expressed candidates, among which protein candidates were subsequently validated by ELISAs. Transcriptomic analysis revealed altered pathways in the BALF of children with PIBO, including pathways related to epithelial differentiation, inflammatory responses, and metabolic processes involving amino acids, purines, lipids, and vitamins. Proteomic analysis further revealed epithelial injury, inflammatory activation, tissue remodeling, and metabolic dysregulation in PIBO patients. Protein–protein interaction (PPI) network analysis identified CXCL8 (interleukin-8, IL-8) as the central hub. Integrative transcriptomic-proteomic correlation analysis further revealed that CXCL8 transcript levels were correlated with the greatest number of differentially expressed proteins (DEPs). Subsequent ELISA validation confirmed elevated CXCL8 protein levels in children with PIBO, which were positively correlated with the predicted FEV1

During molecular surveillance of human adenoviruses (HAdVs) in children hospitalized with acute lower respiratory tract infections in Beijing, China, during 2014-2024, the most prevalent genotypes were HAdV-B114 (53.85%) and HAdV-B7 (27.18%). A novel recombinant genotype, HAdV-B117, was identified in 2 children <5 years of age with severe community-acquired pneumonia and serious complications. Genomic analysis revealed that HAdV-B117 arose from HAdV-B114 (P7H3F3) with the fiber gene from HAdV-B7. We observed amino acid substitutions and deletions in the pivotal regions of 3 major capsid proteins, and some were predicted to alter the protein structure. In vitro, the replication kinetics of HAdV-B117 were similar to those of HAdV-B3 and HAdV-B7. Clinical manifestations resembled severe pneumonia caused by HAdV-B3 or HAdV-B7. Both children recovered after treatment. The emergence of HAdV-B117 highlights the need for continuous genomic surveillance of HAdVs to detect novel recombinants with potential public health effects.

To evaluate the efficacy and safety of inhaled ambroxol solution in improving sputum of lower respiratory tract infections (LRTIs) in children. This study was a randomized, double-blind, parallel-group, placebo-controlled, multicenter trial. The patients were administered inhaled ambroxol or a placebo twice a day for 7 days. And researchers collected efficacy and (or) safety indicators every day during the course. A total of 236 children were randomly assigned to receive ambroxol or placebo (1:1). At all visit points after the medication, the mean difference of cough score with the baseline between the two groups was statistically significant (P < 0.05). Compared with the baseline, the phlegm-sound scores in the throat of the experimental group decreased more on the 1st, 2nd, and 3rd days after administration (P < 0.05). But there was no difference in pulmonary rale scores. The occurrence of adverse events in the experimental group was lower (21.37% vs. 35.59%, P = 0.021), and the incidence of adverse reactions was similar between the two groups (2.56% vs. 5.08%, P = 0.499). Inhaled ambroxol solution could improve the sticky sputum symptoms in children with LRTIs and is safe in clinical application. Further research is needed to confirm these findings. The study was retrospectively registered on June 14, 2023, at https://www.chictr.org.cn/ under the number ChiCTR2300072466.

BACKGROUND:Mycoplasma pneumoniae (MP) is a major cause of pediatric respiratory tract infections (RTIs), with recent increases in incidence and macrolide resistance. The epidemiology of MP, macrolide-resistant MP (MRMP), co-infection patterns, and their relationship with disease severity in the post-COVID era remain poorly understood. We analyzed temporal trends in MP infection and MRMP prevalence and assessed their association with severe community-acquired pneumonia (SCAP). METHODS:Children aged < 18 years hospitalized with RTIs at Beijing Children's Hospital were retrospectively enrolled during 2018-2024. Respiratory samples were tested for MP and macrolide resistance mutations. Data on co-infecting bacterial and viral pathogens were collected in clinical practice and retrospectively included in this study. We analyzed temporal trends and risk factors for SCAP. RESULTS:Among 8,453 children, MP-positive patients accounted for 39.7%, declining to 17.0% in 2021 and rising sharply to 62.8% in 2024. The highest MP-positivity rates were seen in children aged 5-9 years, although a notable increase occurred in children aged < 5 years in 2024. MRMP was detected in 96.9% of MP-positive cases, with resistance rates > 95% from 2022. After 2021, co-infections were detected in 19.9% of cases tested for bacterial and viral pathogens, most commonly involving human rhinovirus-MP, Haemophilus influenzae-MP, and Streptococcus pneumoniae-MP. Risk factors for SCAP included female sex, age > 5 years, cold season onset, pure MP infection, and MP co-infection. MRMP was not an independent predictor of SCAP. CONCLUSIONS:The burden of MP infection has resurged post-COVID, with sustained high macrolide resistance and evolving co-infection patterns. Our findings underscore the importance of ongoing surveillance and tailored management strategies for pediatric MP infections.

ABSTRACT Importance Although macrolides combined with glucocorticoid therapy have demonstrated efficacy in preventing long‐term pulmonary lesions of severe Mycoplasma pneumoniae pneumonia (MPP), evidence regarding glucocorticoid dose is lacking. Objective To evaluate the effects of low‐ and high‐dose methylprednisolone on the risk of long‐term pulmonary lesions for children with severe MPP when combined with azithromycin. Methods This randomized, parallel‐controlled, multicenter clinical trial was conducted in mainland China and enrolled pediatric patients hospitalized with severe MPP. A total of 424 enrolled patients were randomized (allocation ratio of 1:1) to azithromycin combined with either a low‐dose [2 mg/(kg·d)] or a high‐dose [10 mg/(kg·d)] methylprednisolone treatment for 3 d followed by tapering over 12 d. The primary outcome was the incidence of composite adverse outcomes, including atelectasis, bronchiectasis, or bronchiolitis obliterans 6 months after treatment. Results A total of 118 (27.8%) developed adverse pulmonary lesions at 6 months after treatment; 66 of 211 (31.3%) in the high‐dose methylprednisolone group and 52 of 213 (24.4%) in the low‐dose group, respectively. The risk ratio of long‐term pulmonary lesions in a high‐dose group to those in a low‐dose group was 1.28 (95% confidence interval [95% CI]: 0.94–1.75). In addition, the risk of hypertension in the high‐dose group (8.1%, 17 of 211) was higher than that in the low‐dose group (1.4%, three of 213), with a risk ratio of 5.72 (95% CI: 1.70–19.23) Interpretation Azithromycin combined with low‐dose methylprednisolone demonstrates non‐inferior efficacy in reducing pulmonary lesions at 6‐month follow‐up compared to combined with high‐dose methylprednisolone while exhibiting a more favorable safety profile.

Human adenovirus type 108 (HAdV-108) has been detected in multiple countries, including China, and is associated with severe acute respiratory infection (ARI) in children, with reported fatalities. However, studies on HAdV-108 remain limited. This study aimed to investigate the clinical and genetic characteristics of HAdV-108 in ARI children in China. From 2014 to 2024, 6720 respiratory samples were collected from hospitalized children with ARI at ten hospitals across northern and southern China, of which 505 (7.51%) tested positive for HAdV. The whole-genome and three major capsid protein genes were amplified and sequenced for bioinformatics analysis, which revealed that among 317 HAdV-isolated samples, 21 (6.62%) were identified as HAdV-108, ranking third after HAdV-114 and HAdV-7. Clinical analysis of HAdV-108-positive cases showed that the main manifestations were cough and fever. Seven children had gastrointestinal symptoms, and two children without underlying diseases were diagnosed with severe pneumonia. Phylogenetic analysis of whole-genome sequences revealed distinct predominant epidemic branches between domestic and international strains, with one strain obtained in this study forming an independent branch. Hexon protein exhibited the fastest evolution rate, lowest identity, and greatest amino acid variability, while fiber protein displayed the slowest evolution rate, highest identity, and greatest conservation and stability. Compared with the earliest reported HAdV-108 strain, three amino acid deletions were identified in the RGD loop region of penton base protein, resulting in potential structural change. Recombination analysis identified five distinct recombination patterns. In vitro experiments demonstrated that HAdV-108 had proliferation capacity comparable to other species C adenoviruses. In summary, HAdV-108 has persistently circulated in China, causing severe ARIs and concurrent gastrointestinal manifestations. Cluster3 was the predominant epidemic branch in China. HAdV-108 exhibited significant intra-type genetic variation, with random and diverse recombination events.

Primary ciliary dyskinesia (PCD) is a group of genetically heterogeneous disorders characterized by clinical manifestations resulting from abnormal ciliary motility. Mutations in critical genes, such as Cyclin O (CCNO), have been associated with severe respiratory disease, though limited data are currently available. Here we show that CCNO deficient ciliated cells can only form a reduced number of fully functional centrioles that can mature into ciliated basal bodies, and their transport and anchoring to the top of the plasma membrane are abnormal. Furthermore, we observed that CCNO localizes not only in the cytoplasm but also in the nucleus during the early stages of ciliogenesis, and this dual localization persists into adulthood. Transcriptome analysis revealed downregulation of genes involved in cilia assembly and movement, along with altered transcription factors associated with ciliation upon CCNO depletion. These findings indicate that CCNO may serve as a key regulator in the transcriptional regulation of multiciliogenesis.

Background: The epidemiological data of Streptococcus pneumoniae isolates are important for the practice of treatment and prevention. This research aimed to explore the epidemiological characteristics of pediatric S. pneumoniae isolated from outpatients and inpatients. Methods: S. pneumoniae were isolated from unsterile samples of inpatients and outpatients younger than five years old between March 2013 and February 2014. The serotypes were determined by diagnostic pneumococcal antisera, and resistance against 13 antibiotics was tested by either the E-test or the disc diffusion method. The sequence types (STs) were analyzed with multilocus sequence typing (MLST). Results: The five dominant serotypes obtained from inpatients were 19F(32.9%), 19A(20.7%), 23F(10.7%), 6A(10.0%), and 14 (8.6%), while those in the outpatients were 19F (13.6%), 23F (12.9%), 6A (10.0%), 6B (10.0%), and 19A (7.9%). The coverage rates of the 7-, 10- and 13-valent pneumococcal vaccine formulations were high. The non-susceptibility to penicillin, cefuroxime, imipenem, erythromycin, and trimethoprim-sulfamethoxazole among the inpatient isolates were 7.1%, 92.8%, 65.7%, 100%, and 85.0%, respectively, while those among the outpatient isolates were 0.7%, 50.0%, 38.6%, 96.4%, and 65.7%, respectively. There were 45 and 81 STs detected from the pneumococci isolated from inpatients and outpatients, respectively. CC271 was more prevalent in inpatients. Conclusions: The pneumococcal vaccine related serotypes were still prevalent either in inpatient department or in outpatient department, which with serious antibiotic resistance. These results might be helpful for understanding the epidemiology of S. pneumoniae in Beijing. PCVs can prevent vaccine related serotypes. Therefore, universal immunization of PCVs should be implemented to prevent the spread of vaccine related serotypes of S. pneumoniae .

This paper retrospectively analysed the prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) in some parts of China. Between January 2013 and December 2019, we collected 4,145 respiratory samples, including pharyngeal swabs and alveolar lavage fluid. The highest PCR-positive rate of M. pneumoniae was 74.5% in Beijing, the highest resistance rate was 100% in Shanghai, and Gansu was the lowest with 20%. The highest PCR-positive rate of M. pneumoniae was 74.5% in 2013, and the highest MRMP was 97.4% in 2019; the PCR-positive rate of M. pneumoniae for adults in Beijing was 17.9% and the MRMP was 10.48%. Among the children diagnosed with community-acquired pneumonia (CAP), the PCR-positive and macrolide-resistant rates of M. pneumoniae were both higher in the severe ones. A2063G in domain V of 23S rRNA was the major macrolide-resistant mutation, accounting for more than 90%. The MIC values of all MRMP to erythromycin and azithromycin were >= 64 mu g/ml, and the MICs of tetracycline and levofloxacin were <= 0.5 mu g/ml and <= 1 mu g/ml, respectively. The macrolide resistance varied in different regions and years. Among inpatients, the macrolide-resistant rate was higher in severe pneumonia. A2063G was the common mutation, and we found no resistance to tetracycline and levofloxacin.

Human adenovirus (HAdV) is an important pathogen causing acute respiratory infection (ARI) in children. Many countries, including China, have experienced sporadic or outbreaks related to HAdV-4, and death cases were reported. However, there is little research on HAdV-4 and the epidemic situation of HAdV-4 in China is little known. This study was designed to comprehend the prevalence and genetic characteristics of HAdV-4 in ARI children in China. Respiratory tract samples from ARI children hospitalized in six hospitals of Northern and Southern China from 2017 to 2020 were collected for HAdV detection and typing. Clinical information was collected from HAdV-4 positive patients for clinical characteristics and epidemiological analysis. The main capsid proteins and the whole genome sequences were amplified and sequenced for bioinformatics analysis. There were 2847 ARI children enrolled, and 156 (5.48