A Multicenter Study of Viral Aetiology of Community-Acquired Pneumonia in Hospitalized Children in Chinese Mainland

Community-acquired pneumonia(CAP) is one of the leading causes of morbidity and mortality in children worldwide.In this study,we aimed to describe the aetiology of viral infection of pediatric CAP in Chinese mainland.During November2014 to June 2016,the prospective study was conducted in 13 hospitals.The hospitalized children under 18 years old who met the criteria for CAP were enrolled.The throat swabs or nasopharyngeal aspirates(NPAs) were collected which were then screened 18 respiratory viruses using multiplex PCR assay.Viral pathogens were present in 56.6%(1539/2721) of the enrolled cases,with the detection rate of single virus in 39.8% of the cases and multiple viruses in 16.8% of the cases.The most frequently detected virus was respiratory syncytial virus(RSV)(15.2%,414/2721).The highest detection rate of virus was in <6-month-age group(70.7%,292/413).RSV,human metapneumovirus(HMPV),human parainfluenza viruses(HPIVs) and influenza B virus(Flu B) showed the similar prevalence patterns both in north and south China,but HPIVs,Flu A,human bocavirus(HBoV),human adenovirus(HAdV) and human coronaviruses(HCoVs) showed the distinct circulating patterns in north and south China.Human enterovirus/human rhinovirus(HEV/HRV)(27.6%,27/98),HBoV(18.4%,18/98),RSV(16.3%,16/98) and HMPV(14.3%,14/98) were the most commonly detected viruses in severe pneumonia cases with single virus infection.In conclusion,viral pathogens are frequently detected in pediatric CAP cases and may therefore play a vital role in the aetiology of CAP.RSV was the most important virus in hospitalized children with CAP in Chinese mainland.

Clinical characteristics and molecular epidemiology of human metapneumovirus in children with acute lower respiratory tract infections in China, 2017 to 2019: A multicentre prospective observational study

Human metapneumovirus(HMPV) infection is one of the leading causes of hospitalization in young children with acute respiratory illness. In this study, we prospectively collected respiratory tract samples from children who were hospitalized with acute lower respiratory tract infection in six hospitals in China from 2017 to 2019. HMPV was detected in 145 out of 2733 samples(5.3%) from the hospitalized children. The majority of HMPV-positive children were under the age of two(67.6%), with a median age of one year. HMPV can independently cause acute lower respiratory tract infection in young children, while all patients showed mild clinical symptoms. Of all the co-infected patients, HMPV was most commonly detected with enterovirus(EV) or rhinovirus(RhV)(38.0%),followed by respiratory syncytial virus(RSV)(32.0%). The highest detection rate occurred from March to May in both northern and southern China. Out of 145 HMPV positive samples, 48 were successfully typed, of which 36strains were subgrouped into subtypes A2c(75%), eight strains were included in subtype B1(16.7%), and four strains were included in subtype B2(8.3%). Moreover, 16 A2c strains contained 111-nucleotide duplications in the G gene. Twenty-seven complete HMPV genomes were successfully obtained, and 25(92.6%) strains belonged to subtype A2c, whereas one strain was included in subgroup B1 and another was included in subgroup B2. A total of 277 mutations were observed in the complete genomes of 25 A2c strains. All results presented here improve our understanding of clinical characteristics and molecular epidemiology of HMPV infection in children.

A multi-center study on Molecular Epidemiology of Human Respiratory Syncytial Virus from Children with Acute Lower Respiratory Tract Infections in the Mainland of China between 2015 and 2019

Human respiratory syncytial virus(RSV) is a major pathogen of acute lower respiratory tract infection among young children. To investigate the prevalence and genetic characteristics of RSV in China, we performed a molecular epidemiological study during 2015–2019. A total of 964 RSV-positive specimens were identified from 5529 enrolled patients during a multi-center study. RSV subgroup A(RSV-A) was the predominant subgroup during this research period except in2016. Totally, 535 sequences of the second hypervariable region(HVR-2) of the G gene were obtained. Combined with182 Chinese sequences from GenBank, phylogenetic trees showed that 521 RSV-A sequences fell in genotypes ON1(512),NA1(6) and GA5(3), respectively;while 196 RSV-B sequences fell in BA9(193) and SAB4(3). ON1 and BA9 were the only genotypes after December 2015. Genotypes ON1 and BA9 can be separated into 10 and 7 lineages, respectively. The HVR-2 of genotype ON1 had six amino acid changes with a frequency more than 10%, while two substitutions H258 Q and H266 L were co-occurrences. The HVR-2 of genotype BA9 had nine amino acid substitutions with a frequency more than10%, while the sequences with T290 I and T312 I were all from 2018 to 2019. One N-glycosylation site at 237 was identified among ON1 sequences, while two N-glycosylation sites(296 and 310) were identified in the 60-nucleotide duplication region of BA9. To conclusion, ON1 and BA9 were the predominant genotypes in China during 2015–2019. For the genotypes ON1 and BA9, the G gene exhibited relatively high diversity and evolved continuously.

Genetic Analysis of Human Adenovirus Type 7 Strains Circulating in Different Parts of China

To investigate the molecular epidemiology and genetic variation of human adenovirus type 7(HAdV-7)in children with acute respiratory infections(ARI)in China.HAdV-7-positive respiratory samples collected from children with ARI in Beijing,Shijiazhuang,Wenzhou and Guangzhou from 2014–2018 were selected for gene amplification and sequence analysis.Fifty-seven HAdV-7 clinical strains with hexon,penton base and fiber gene sequences were obtained.Meanwhile17 strains were selected randomly from different cities for whole genome sequencing.Phylogenetic and variation analyses were performed based on the obtained sequences,HAdV-7 prototype strain Gomen(AY594255),vaccine strains(AY495969 and AY594256)and representative sequences of strains.The phylogenetic trees constructed based on whole genome sequences,major capsid protein genes(hexon,penton base and fiber)and the early genes(E1,E2,E3 and E4)were not completely consistent.The HAdV-7 strains obtained in this study always clustered with most of the circulating strains worldwide from the 1980 s to the present.Compared with the HAdV-7 prototype strain Gomen(AY594255),some amino acid mutations in loop1 and loop2 of hexon and the RGD loop region of the penton base gene were observed.Recombination analysis showed that partial regions of 55 k Da protein and 100 kDa hexon-assembly associated protein genes among all HAdV-7 strains in this study were from HAdV-16 and HAdV-3,respectively.Our study demonstrated the molecular evolution characteristics of HAdV-7 strains circulating in China and provided basic reference data for the prevention,control and vaccine development of HAdV-7.

Pandemic 2009 influenza A(H1N1)-associated deaths among children in China:A retrospective analysis

Importance:A cluster of influenza-associated deaths occurred among children during pandemic 2009 influenza A(H 1N1)in China,but the risk factors and causes for death have not been clarified.Objective:We describe the clinical findings regarding 2009 influenza A(H1N1)-associated pediatric deaths in China,including the risk factors for death.Methods:The definition of 2009 influenza A(H1N1)-associated pediatric death is death in a child who is younger than 14 years and has laboratory-confirmed influenza.We collected data of total 810 hospitalized patients with 2009 influenza A(H 1N 1)infection from September 2009 to February 2010 in 17 hospitals across China.The clinical characteristics,laboratory abnormalities,and treatment course were retrospectively studied.Results:Of the 810 patients hospitalized with 2009 influenza A(H1N1)infection,19(2.3%)died.Ten patients died from severe pneumonia and acute respiratory distress syndrome;eight died from encephalopathy/encephalitis;one died from secondary fungal meningitis.Patients who died were more likely than patients who survived to have neutrophilia,lymphopenia,elevated C-reactive protein,and elevations of lactate dehydrogenase,creatine kinase,creatine kinase-MB,aspartate aminotransferase and alanine aminotransferase.There were no significant differences in the median age,median time from onset of illness to admission,underlying chronic disease,and initiation of antiviral therapy within 48 hours of illness onset,between patients who died and those who survived.Interpretation:The risk factors for pediatric death associated with 2009 influenza A(H 1N 1)infection are different from those of seasonal influenza.The most common causes of death are viral pneumonia,acute respiratory distress syndrome,and encephalopathy/encephalitis.