Introduction:In China, no standardized single-nucleotide polymorphism (SNP) scheme exists for varicella-zoster virus (VZV) genotyping. The 5-SNP scheme with two amplicon gene fragments lacks systematic validation. This study aimed to evaluate the accuracy and applicability of this genotyping method. Methods:A total of 280 complete genomes were genotyped using 5 SNPs extracted from ORF22 (four SNPs) and ORF38 (one SNP) fragments. The results were compared with those of the phylogenetic clustering method as a reference. Concordance with reference was used to estimate the accuracy of the SNP scheme. The evaluated SNP scheme was applied to a national VZV surveillance screen containing 549 clinical samples from 17 Chinese provincial-level administrative divisions (2017-2026). Results:A 97.9% concordance was observed between the 5-SNP scheme and phylogenetic clustering methods. The 2.1% discordance was mostly attributed to putative recombination and early circulation of strains from patients with herpes zoster. During the national VZV surveillance screening, 434 samples were amplified, sequenced, and genotyped using a 5-SNP scheme. Of the genotyped samples, 90.3% and 8.8% were identified as clades 2 and 5, respectively, using four ORF22 SNPs, and the remaining 0.9% as clade 4, using ORF38 SNP. All samples showed 100% intragenotypic SNP profile consistency. Conclusion:The unified 5-SNP scheme is accurate and practical for VZV surveillance in China; however, periodic evaluation is required.

Abstract Background Enteroviruses (EVs) are important pathogens that cause neurological and systemic infections in children. Currently, only hand, foot, and mouth disease (HFMD) is monitored in China, indicating a lack of systematic surveillance for other EV-related diseases. Additionally, long-term epidemiological data on pediatric EV infections in Beijing are scarce. The aim of this study was to describe the clinical and epidemiological characteristics of children with EV infection in Beijing over a ten-year period. Methods In this retrospective study, all hospitalized patients who underwent EV RNA detection using a fluorescence‑based real‑time PCR assay between July 2016 and July 2025 were included. Demographic, clinical, and laboratory information was retrieved from the hospital’s electronic medical record system. Results A total of 8,426 patients was included in this study, and 236 cases (2.80%) tested positive for EVs. Notably, males exhibited a higher detection rate (3.14%, 160/4,940) than females (2.18%, 76/3,486). Moreover, children aged 3 to < 6 months (5.26%, 13/247) and those aged 3 to < 7 years (4.51%, 56/1243) had higher detection rates than other age groups. In terms of seasonal patterns, EV infections demonstrated distinct peak in summer and autumn. Among the 205 patients whose clinical information was complete, viral encephalitis (VE) was identified as the most predominant disease (55.12%, 113/205), particularly among children aged 3 to < 6 years (39.82%, 45/113) and those aged 28 days to < 3 months (10.62%, 12/113). This was followed by myocardial injury/myocarditis (23.41%, 48/205), pneumonia (22.93%, 47/205), hepatic dysfunction (14.63%, 30/205), multiple organ dysfunction syndrome (MODS) (8.78%, 18/205), HFMD (7.80%, 16/205), herpangina (3.90%, 8/205), and arrhythmia (3.41%, 7/205). In this study, 98.05% of the patients had a favorable prognosis, with a mortality rate of 1.95% (4/204). Conclusions Diseases related to EV infection are among the important reasons for hospitalization in children, among which the top three diseases are encephalitis/meningitis, myocarditis/myocardial damage, and pneumonia. EV infection mainly affects infants and young children under 7 years of age, with the peak incidence in summer and autumn seasons. Clinical trial number Not applicable.

OBJECTIVES:Human adenovirus type 7 (HAdV-7) has caused outbreaks of acute respiratory infections (ARIs) among children in multiple countries. This study aimed to investigate the clinical and genetic characteristics of HAdV-7 in hospitalized children with ARIs in China. METHODS:Respiratory samples were collected from hospitalized children with ARIs at 10 hospitals across Northern and Southern China between 2014 and 2025 for HAdV detection and genotyping. Clinical data of HAdV-7-positive patients were collected for clinical characteristics analysis. The whole genomes of isolated HAdV-7 strains were sequenced for bioinformatics analysis with those selected from GenBank. RESULTS:Among 250 HAdV-positive samples, 79 (31.60%) were HAdV-7, ranking second only to HAdV-114 (46.80%). Patients primarily presented with fever, cough, and sputum production. Some cases also complicated with gastrointestinal and neurological symptoms, skin rashes, and ocular diseases. Severe pneumonia occurred in 54.43% of patients, with one death. Whole genome sequence phylogenetic analysis revealed that HAdV-7 could be divided into two clusters. Cluster 1, including the prototype strain, had been rarely reported globally since the discovery of HAdV-7. Cluster 2 was the predominant cluster circulating worldwide, including China. Three novel amino acid substitutions were observed in the Loop 1 region of the Hexon protein, which might be associated with the severe disease phenotype and resulted in the emergence of a positive selection site. Recombination analysis identified a recombination event, which occurred as early as 1988. In vitro experiments demonstrated that HAdV-7 had comparable proliferation capacity with other genotypes of the HAdV-B species. CONCLUSIONS:HAdV-7 was an important pathogen of hospitalized children with ARIs in China, and associated with severe diseases and even death. Cluster 2 was the predominant epidemic cluster worldwide. Although the HAdV-7 genome was relatively conserved and stable, novel amino acid mutations have occurred.

Enteroviruses (EVs), which include numerous types, are among the most common pathogens causing infections in children. EVs can cause diverse diseases, including herpangina, hand-foot-and-mouth disease, myocarditis, pneumonia, meningitis, encephalitis, and acute flaccid paralysis. Severe cases may result in pediatric mortality, posing substantial threats to child health and public health. The diversity of EV types combined with rapid viral evolution and antigenic variation presents formidable challenges for EV prevention and control, with dominant genotypes being continuously replaced by emerging variants and novel subtypes. EV invades host cells through specific receptors and hijacks cellular machinery for self-replication, engaging in complex interactions with the host while evolving multiple mechanisms to evade host immune responses. Currently, no specific anti-EV agents are available, and treatment remains primarily supportive and symptomatic. Effective prevention and control strategies for EV are limited, and vaccines are currently available only against selected EV serotypes. This review systematically examines EV infections from multiple perspectives, including epidemiology, virology, viral entry mechanisms, virus-host interactions, clinical diagnosis and management, prevention and control measures, with the aim of providing insights and references for research on EV pathogenesis, precision clinical diagnosis and treatment, and the development of antiviral therapies and vaccines.

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.

Ferroptosis, characterized by lipid peroxidation and iron-dependent oxidative damage, is a crucial factor in various diseases. Although researchers have extensively characterized ferroptosis in cancer and neurodegenerative disorders, its interaction with pathogenic infections remains underexplored. Recent research indicates that ferroptosis contributes to host cell damage during pathogen invasions, impacting disease outcomes. This review summarizes the characteristics, mechanisms, and regulatory networks of ferroptosis. It delineates the key regulatory steps of ferroptosis during infections caused by various pathogens, including viruses, bacteria, fungi, and parasites. Additionally, it examines changes in host markers and related signaling pathways. Furthermore, this review explores the potential similarities and differences among these pathogens and discusses therapeutic strategies for addressing pathogen-related diseases through ferroptosis-dependent mechanisms.

Enterovirus (EV) infections represent a significant global and national health concern in children, leading to various complications. Although most children with EV infections generally have a favorable prognosis, a small proportion may still develop severe complications. This study aimed to analyze the epidemiological characteristics, disease spectrum, and disease burden of EV infections in China. A total of 163,714 hospitalized children with EV infections from 37 member hospitals of the Futang Research Center of Pediatric Development were identified between Jan 1st, 2016 and Dec 31st, 2023, accounting for 1.49% of all pediatric hospitalizations. Most cases occurred in infants aged 28 days to ≤ 1 year (42.29%) and toddlers aged 1 to ≤ 3 years (39.93%), with a male predominance (male-to-female ratio, 1.62 : 1). Severe cases of EV infections can be life-threatening and increase the burden of disease. The median LOS for EV infections were 5 days, with an average hospitalization cost of $587.37. EV infections can affect multiple organs, including the heart, brain, and respiratory system and were associated with severe complications, including myocarditis, encephalitis, and meningitis. These findings underscore the substantial disease burden of EV infections and highlight the need for targeted prevention strategies in young children.

Echovirus 6 (E6) infection, a member of enterovirus, can cause severe neurological complications, particularly viral meningitis and encephalitis in children. However, the shortage of effective animal models has substantially impeded research on its pathogenesis and the advancement of therapeutic strategies. This study established and characterized a novel E6 infection model by employing transgenic (Tg) mice carrying the human neonatal Fc receptor (hFcRn). Following intracranial injection via the foramen magnum with E6, hFcRnTg mice exhibited significantly lower survival rates, impaired weight gain, and more severe clinical manifestations compared to wild-type control. Elevated levels of virus were detected in the brain, spinal cord, and muscle tissues of hFcRnTg mice, accompanied by substantial pathological changes, including neuronal damage, glial cell proliferation, and inflammatory infiltration. Immunofluorescence analyses confirmed active viral replication in the thalamus, meninges, and hippocampus. Extensive cytokine analysis showed increased concentrations of pro-inflammatory mediators, including MCP-1, IFN-γ, and TNF-α. Transcriptomic and proteomic analyses revealed enhanced immune pathways and suppressed metabolic processes, with key proteins MyD88, Cxcl10, and Irf3 central to the host response. Notably, our findings suggest that E6 infection may engage ZBP1-centered PANoptosis, although the underlying mechanisms require further validation. This model provides a valuable tool for investigating E6 pathogenesis and evaluating potential therapeutic strategies.

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.

Echovirus 11 (E11) infections can easily cause neonatal sepsis, which is a life-threatening disease. However, the pathogenesis of E11 infections remains poorly understood. Furthermore, the absence of an effective animal model that accurately reflects disseminated neonatal infection has hindered research progress. Hence, we aimed to establish a precise disease mouse model closely resembling E11 associated human neonatal conditions. Three-day-old human neonatal Fc receptor (hFcRn) transgenic mice were administered an optimized dose of E11 through intraperitoneal (IP) injection. E11-infected mice exhibited severe clinical symptoms, including weight loss, limb paralysis, and even death. Viral loads were detected across multiple organs, such as muscle, spinal cord, and intestine, with the highest load in muscle (1 × 105-1 × 107 copies/mg). Additionally, liver and kidney function (ALT, AST and Cr), cardiac enzymes (CK-MB), and coagulation parameters (FDP) were markedly abnormal in the E11 group, in which ALT level showed 3.5 times higher than the normal group. Furthermore, in situ hybridization revealed E11 RNA in the heart, liver, lungs, and brain, with the highest levels in the heart and liver. Serum cytokine analysis showed significant elevation of MCP-1, IL-18, IL-22, and RANTES, with MCP-1 reaching levels as high as 2590 pg/mL. Histopathological examination revealed extensive pathological changes in multiple tissues. The successful establishment of the disseminated neonatal E11 infection model relies on several key factors, including the use of 3-day-old mice, an increased dosage of the infectious agent, an appropriate infection route via IP injection, and the use of viral strains obtained from the clinical case of neonatal mortality. In summary, this mouse model serves as a valuable tool for investigating the pathogenic mechanisms of E11 infection associated disseminated neonatal infection, offering a stable platform for the development and evaluation of related vaccines and therapeutic drugs.

Acute lower respiratory tract infections (ALRTIs) are a leading cause of mortality in young children worldwide due to human respiratory syncytial virus (RSV). The aim of this study was to monitor genetic variations in RSV and provide genomic data support for RSV prevention and control. A total of 105 complete RSV genome sequences were determined during 2017-2020. Phylogenetic analysis showed that all of the RSVA sequences were of genotype ON1, and all of the RSVB sequences were of genotype BA9. Notably, a phylogenetic tree based on the whole genome had more branches than a tree based on the G gene. In comparison to the RSV prototype sequences, 71.43

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

ABSTRACT Human parainfluenza viruses (HPIVs) are a significant cause of acute lower respiratory tract infections (ALRTIs) among young children and elderly individuals worldwide. The four types of HPIVs (HPIV1–4) can cause recurrent infections and pose a significant economic burden on health care systems globally. However, owing to the limited availability of complete genome sequences, the genetic evolution of these viruses and the development of vaccines and antiviral treatments are hampered. To address this issue, this study utilized next-generation sequencing to obtain 156 complete genome sequences of HPIV1–4, which were isolated from hospitalized children with ALRTIs in six regions of China between 2015 and 2021. This study revealed multiple clades, lineages, or sublineages of HPIVs circulating in mainland China, with a novel clade D of HPIV1 identified as geographically restricted to China. Moreover, this study identified the endemic dominant genotype of HPIV3, lineage C3, which has widely spread and continuously circulated in China. Bioinformatic analysis of the genome sequences revealed that the proteins of HPIV3 possessed the most variable sites, with the P protein showing more diversity than the other proteins among all types of HPIVs. The HN proteins of HPIV1–3 are all under negative/purifying selection, and two amino acid substitutions in the HN proteins correspond to known mAb neutralizing sites in the two HPIV3 strains. These findings provide crucial insights into the genetic diversity and evolutionary dynamics of HPIVs circulating among children in China and may facilitate research on the molecular diagnosis, vaccine development, and surveillance of HPIVs. IMPORTANCE Phylogenetic analysis revealed the prevalence of multiple clades, lineages, or sublineages of human parainfluenza viruses (HPIVs) circulating in mainland China. Notably, a unique evolutionary branch of HPIV1 containing only Chinese strains was identified and designated clade D. Furthermore, in 2023, HPIV3 strains from Pakistan and Russia formed a new lineage within clade C, named C6. The first HPIV4b sequence obtained in this study from China belongs to lineage C2. Evolutionary rate assessments revealed that both the HN and whole-genome sequences of HPIV3 presented the lowest evolutionary rates compared with those of the other HPIV types, with rates of 6.98E−04 substitutions/site/year (95% HPD: 5.87E−04 to 8.25E−03) and 5.85E−04 substitutions/site/year (95% HPD: 5.12E−04 to 6.62E−04), respectively. Recombination analysis revealed a potential recombination event in the F gene of an HPIV1 strain in this study. Additionally, all the newly obtained HPIV1–3 strains exhibited negative selection pressure, and two mutations were identified in the HN protein of two HPIV3 strains at monoclonal antibody-binding sites.

A resurgent outbreak of children respiratory syncytial virus (RSV) infection occurred on April 2023, Beijing. To elucidate the dominant genotypes and molecular characteristics of RSV isolates, totally 11 partial G gene sequences were obtained. Six RSVA and five RSVB isolates were clustered into ON1 and BA9 genotypes. Amino acid substitutions T113I, V131D, H258Q, and H266L were co-occurrences in four RSVA isolates. One strain had a substitution to S174N in T cell epitope of RSVA G protein. In RSVB G protein, P237L, P247T, K258N/S, H259Y, T266I, N296Y, T302I, and E305K were newly found but not in our previous study.

Abstract Background Acute gastroenteritis (AGE) causes significant morbidity in children worldwide; however, the disease burden of children hospitalized with viral gastroenteritis in China has been rarely described. Through this study, we analyzed the data of hospitalized children with viral gastroenteritis to explore the changes in the epidemiology and clinical characteristics of viral gastroenteritis in the mainland of China. Methods Data were extracted from Futang Children's Medical Development Research Center (FRCPD), between 2016 and 2020, across 27 hospitals in 7 regions. The demographics, geographic distribution, pathogenic examination results, complications, hospital admission date, length of hospital stays, hospitalization charges and outcomes were collected and analyzed. Results Viral etiological agents included rotavirus (RV), adenovirus (ADV), norovirus (NV) and coxsackievirus (CV) that were detected in 25,274 (89.6%), 1,047 (3.7%), 441 (1.5%) and 83 (0.3%) cases. There was a higher prevalence of RV and NV infection among children younger than 3 years of age. RV and NV had the highest detection rates in winter, while ADV in summer. Children with viral gastroenteritis were often accompanied by other diseases, such as myocardial diseases (10.98–31.04%), upper respiratory tract diseases (1.20–20.15%), and seizures (2.41–14.51%). Among those cases, the co-infection rate with other pathogens was 6.28%, with Mycoplasma pneumoniae (M. pneumoniae), Epstein-Barr virus (EBV), and influenza virus (FLU) being the most common pathogens. The median length of stay was 5 days, and the median cost of hospitalization corresponded to587 US dollars. Conclusions This finding suggests that viral gastroenteritis, especially those caused by RV, is a prevalent illness among younger children. Co-infections and the presence of other diseases are common. The seasonality and regional variation of viral etiological agents highlight the need for targeted prevention and control measures. Although viral gastroenteritis rarely leads to death, it also results in a significant economic burden on healthcare systems.

Respiratory syncytial virus (RSV) is a significant cause of acute lower respiratory tract infection (ALRTI) in children under five years of age. Between 2017 and 2021, 396 complete sequences of the RSV F gene were obtained from 500 RSV-positive throat swabs collected from ten hospitals across nine provinces in China. In addition, 151 sequences from China were sourced from GenBank and GISAID, making a total of 549 RSV F gene sequences subjected to analysis. Phylogenetic and genetic diversity analyses revealed that the RSV F genes circulating in China from 2017 to 2021 have remained relatively conserved, although some amino acids (AAs) have undergone changes. AA mutations with frequencies ≥ 10% were identified at six sites and the p27 region: V384I (site I), N276S (site II), R213S (site Ø), and K124N (p27) for RSV A; F45L (site I), M152I/L172Q/S173L/I185V/K191R (site V), and R202Q/I206M/Q209R (site Ø) for RSV B. Comparing mutational frequencies in RSV-F before and after 2020 revealed minor changes for RSV A, while the K191R, I206M, and Q209R frequencies increased by over 10% in RSV B. Notably, the nirsevimab-resistant mutation, S211N in RSV B, increased in frequency from 0% to 1.15%. Both representative strains aligned with the predicted RSV-F structures of their respective prototypes exhibited similar conformations, with low root-mean-square deviation values. These results could provide foundational data from China for the development of RSV mAbs and vaccines.

Public health threats posed by emerging respiratory infections are a significant concern, particularly in children and infants. Traditional culture-based detection methods are time-consuming and typically require 1-3 days. Herein, we developed and evaluated a 23-plex common respiratory pathogen mass spectrometry assay that enables the simultaneous detection of 18 common respiratory pathogens in children. This assay combines matrix-assisted laser desorption/ionization time of flight mass spectrometry with multiplex reverse transcription-PCR and targets 11 bacterial and 7 viral pathogens (including 10 subtypes), and two internal controls. The detection limit of the common respiratory pathogen mass spectrometry assay was as low as 1 copy/mu L, with no cross-reactivity with other organisms. We assessed the clinical performance of the common respiratory pathogen mass spectrometry assay using respiratory samples from 450 children. The total 450 clinical specimens underwent analysis via matrix-assisted laser desorption/ionization time of flight mass spectrometry, and the outcomes were juxtaposed with those derived from real-time reverse-transcriptase PCR conducted concurrently. The concordance between these methods was 96.0%, and the multiple infection identification rate was 7.1%. This innovative approach enables the simultaneous analysis of numerous outcomes from a solitary examination across 192 specimens within a timeframe of approximately 7 hours, with a dramatically reduced sample use and cost. In summary, the common respiratory pathogen mass spectrometry assay is a sensitive, accurate, and cost-effective method for detecting common respiratory pathogens in children and has the potential to revolutionize the diagnosis of respiratory tract infections. IMPORTANCE This study aimed to present and evaluate a novel co-detection method that enables the simultaneous identification of 11 bacterial and 7 viral pathogens in about 7 hours using matrix-assisted laser desorption/ionization time of flight mass spectrometry. Our approach utilizes a combination of multiplex reverse transcription-PCR and matrix-assisted laser desorption/ionization time of flight mass spectrometry, which overcomes the limitations of conventional assays, which include a long assessment time, technical difficulty, and high costs. As a screening method for common respiratory pathogens in children, common respiratory pathogen mass spectrometry assay has the potential to revolutionize the diagnosis of respiratory tract infections by providing an accurate etiological diagnosis. The common respiratory pathogen mass spectrometry assay is expected to be a critical tool for the diagnosis of respiratory infections in children, offering a more efficient, cost-effective, and accurate approach for the detection of common respiratory pathogens.

BACKGROUND:Stringent nonpharmaceutical interventions (NPIs) have been implemented worldwide to combat the COVID-19 pandemic, and the circulation and seasonality of common respiratory viruses have subsequently changed. There have been few multicentre studies or comparisons of the prevalence of respiratory viruses accounting for community-acquired pneumonia (CAP) in hospitalized children between the pre-COVID period and the period after community and school reopening in the setting of the zero-COVID policy.METHODS:We included 1543 children with CAP who required hospitalization from November 1, 2020 to April 30, 2021 (period 1), and 629 children with the same conditions from November 1, 2018, to April 30, 2019 (period 2), in our study. All respiratory samples from these patients were screened for six respiratory viruses (respiratory syncytial virus [RSV], adenovirus [ADV], influenza A virus [Flu A], influenza B virus [Flu B], parainfluenza virus type 1 [PIV1], and parainfluenza virus type 3 [PIV3]) using a multiplex real-time PCR assay.RESULTS AND CONCLUSIONS:The median ages of the enrolled patients at the time of diagnosis were 1.5 years and 1.0 years for period 1 and period 2, respectively. In period 1, viral pathogens were detected in 50.3% (776/1543) of the enrolled patients. The most frequently identified viral pathogen was RSV (35.9%, 554/1543), followed by PIV3 (9.6%, 148/1543), PIV1 (3.6%, 56/1543), ADV (3.4%, 52/1543), Flu A (1.0%, 16/1543), and Flu B (0.8%, 13/1543). The total detection rates of these six viruses in the peak season of CAP were at the pre-COVID level. The prevalence of Flu A decreased dramatically, and circulation activity was low compared to pre-COVID levels, while the incidence of PIV3 increased significantly. There were no significant differences in the detection rates of RSV, ADV, Flu B, and PIV1 between the two periods. Our results showed that respiratory viruses accounted for CAP in hospitalized children at pre-COVID levels as communities and schools reopened within the zero-COVID policy, although the prevalence aetiology spectrum varied.

Background Sepsis is a systemic inflammatory response syndrome caused by severe infection in children, but cases of sepsis associated with human parainfluenza virus (HPIV) have been rarely reported in newborns. Case presentation We report a case of HPIV-3 positive full-term newborn admitted to the Neonatal Intensive Care Unit of Beijing Children’s Hospital due to hematuria, gloomy spirit, inactivity and loss of appetite for 6 h. He had septic shock when he arrived the Accident & Emergency Department requiring immediate intubation and mechanical ventilation. Intravenous antibiotics were started. He had completely negative response to all anti-shock treatments including fluid resuscitation and vasopressor supports, and died 14 h later. Viral nucleic acid detection and metagenomic next-generation sequencing (mNGS) analyses of nasopharyngeal aspirate and blood specimens verified an HPIV-3 infection, with negative bacterial culture results. The HPIV-3 strain detected in this patient was subtyped as HPIV C3a, and two unreported amino acid mutations were found in the HN protein region. Conclusion The patient had a severe infection associated with HPIV-3, which was the cause of sepsis and septic shock. This study showed the diagnostic value of mNGS in etiological diagnosis, especially in severe neonatal case.

The emergence of multiplex digital polymerase chain reaction (dPCR) and other detection technologies for respiratory pathogens in recent years has facilitated greater understanding of respiratory virus epidemics. In this study, a multiplex dPCR method was developed and evaluated as a means of detecting five respiratory pathogens in children with acute lower respiratory tract infection (ALRTI). With 139 nasopharyngeal swabs collected from children with ALRTI, pathogens were detected using dPCR and quantitative real-time PCR (qPCR) methods. Of those specimens, dPCR detected 86 positive cases, while qPCR identified 84. Moreover, dPCR exhibited higher sensitivity than qPCR, and displayed no cross-reactivity with common respiratory pathogens. These findings suggest that dPCR-based method could become one of the most promising options for acute respiratory pathogen detection.