Humans ; Molecular Epidemiology ; Respiratory Syncytial Virus Infections ; epidemiology ; virology ; Respiratory Syncytial Virus, Human ; genetics

Human Respiratory Syncytial Virus (HRSV) is a serious threat to the population health. The elderly are one of the susceptible populations. The prevalence of HRSV in the elderly is generally higher than that in other age groups except children, which has gradually attracted attention in recent years. This paper reviewed the prevalence, common complications and major complications of HRSV in the elderly, briefly expounded the economic burden of HRSV infection, and proposed that attention should be paid to the disease burden of the elderly after HRSV infection, timely treat common complications, so as to reduce the occurrence of adverse survival outcomes and provide scientific evidence for the prevention and control of HRSV infection in the elderly.
Child ; Humans ; Aged ; Respiratory Syncytial Virus Infections/epidemiology* ; Respiratory Syncytial Virus, Human

Human respiratory syncytial virus (HRSV) is one of the main pathogen causing severe acute lower respiratory tract infections in infants and the elderly, with high incidence rate and mortality worldwide. Vaccine is one of the important measure to prevent infection, transmission and severe disease of HRSV, but currently there is no officially approved preventive vaccine for prevention of HRSV in the world. This paper reviews and analyzes the current research and development progress of HRSV vaccine, summarizes the design routes of different types of HRSV preventive vaccines, and discusses the difficulties and challenges in vaccine research and development, in order to provide reference for the research and development of HRSV vaccine and the development of clinical trials.
Infant ; Humans ; Aged ; Respiratory Syncytial Virus, Human ; Respiratory Syncytial Virus Infections/epidemiology* ; Respiratory Syncytial Virus Vaccines/therapeutic use* ; Respiratory Tract Infections

OBJECTIVE: To find out the prevalence of respiratory syncytial virus (RSV) genotypes in southern Zhejiang Province, China, and to study the genetic characteristics of G protein from subtype A of RSV. METHODS: The lower respiratory tract secretions of children under 5 years of age who were hospitalized for pneumonia and bronchiolitis in three hospitals in southern Zhejiang Province from July 2009 to June 2014 were collected. Direct immunofluorescence assay was used to detect RSV antigens from the collected secretions. A total of 200 samples were randomly selected from RSV-positive specimens in each prevailing year (from July of a specific year to June of the next year). RT-PCR was used to determine RSV subtypes, and the near-full length gene sequence of G protein from subtype A was amplified and sequenced to identify the genotype. RESULTS: A total of 25 449 samples of lower respiratory tract secretions were collected from 2009 to 2014, among which 6 416 (25.21%) samples were RSV-positive. Among the 1 000 RSV-positive specimens randomly sampled, 462 strains (46.2%) were subtype A, and 538 strains (53.8%) were subtype B. Subtype A accounted for 22.5%, 74.5%, 84.5%, 19.0%, and 30.5% of the total strains in each year from 2009 to 2014. A total of 25 RSV subtype A strains were randomly sampled and sent out for bidirectional sequencing in each year, which confirmed 52 positive subtype A strains. Four genotypes of subtype A strains were obtained from the above strains, including NA1 (39 strains), NA4 (1 strain), ON1 (10 strains), and GA2 (2 strains). NA1 was the dominant genotype between 2009 and 2012, and ON1 was the only genotype of subtype A during 2013-2014. The nucleotide homology and amino acid homology between the G protein of subtype A and the prototype strain A2 were 80.7%-89.3% and 74.4%-82.6%, respectively. The nucleotide homology and amino acid homology between the isolates of subtype A were 81.5%-100% and 80.2%-100%, respectively. CONCLUSIONS In southern Zhejiang Province from 2009 to 2014, there was a co-circulation of RSV subtypes A and B, as well as a co-circulation of several different genotypes of RSV subtype A, which had highly variable G protein genes.
Child, Preschool ; China ; Epidemiologic Studies ; Genotype ; Humans ; Infant ; Infant, Newborn ; Phylogeny ; Respiratory Syncytial Virus Infections ; epidemiology ; Respiratory Syncytial Virus, Human

OBJECTIVETo investigate the epidemiological characteristics of respiratory syncytial virus (RSV) subtypes and genotypes in southern Zhejiang province, and to determine whether RSV genotypes are correlated with the disease severity of lower respiratory tract infection (LRTI).

METHODNasopharyngeal secretions (NPS) from children under 5 years of age who were hospitalized with LRTI during 5 consecutive seasons from July 1, 2009 to June 30, 2014 were collected. RSV antigen was determined using direct immunofluorescence (DIF). Two hundred strains of RSV were randomly selected from each epidemic season. RNA was extracted and identified as subtype A or B by using reverse transcription-polymerase chain reaction (RT-PCR), and randomly selected strains of the full length attachment (G) genes of both subtype A and subtype B were amplified by PCR and sequencing. Clinical data were collected, and the disease severity between different genotypes were compared simultaneously.

RESULTOf the total 1 000 randomly selected RSV positive samples, 462 (46.2%) and 538 (53.8%) samples were identified as subtype A and B, respectively. It was found that subtype B predominated in the 2009-2010 and 2012-2014 epidemic seasons and subtype A in 2010-2012 epidemic seasons. A total of 112 strains of complete sequences of G genes were obtained, including four subtype A genotypes NA1, NA4, GA2 and ON1, and six subtype B genotypes BA8-10, BA-C, CB1, and GB2. Phylogenetic analysis revealed that 39/52 (75.0%) subtype A strains were classified as NA1 genotype, followed by ON1 genotype (10/52,19.2%) and 44/60 (73.3%) subtype B strains were classified as BA9 genotype, followed by BA8 genotype (6/60,10.0%). BA9 was the predominant genotype among subtype B except 2010-2011 epidemic season, while NA1 was the predominant genotype among subtype A except 2013-2014 epidemic season. Only ON1 and BA9 genotypes were checked out during 2013-2014 epidemic season. There was statistically significant difference in the average severity score of illness in 39 cases infected with NA1 genotype (4.154) and 44 cases of BA9 genotype (3.341) (U=642.500, P<0.05). Furthermore, in the rate of oxygen uptake, the percentage of those infected with NA1 genotype (33.3%) was higher than those infected with BA9 genotype (13.6%) (χ2=4.544, P<0.05). However, there were no significant difference in the age, clinical symptoms, the percentage of intensive care unit admission, length of hospitalization and the outcome of the disease between NA1 and BA9 infection.

CONCLUSIONThe shift of predominant RSV subtype from 2009 to 2014 were B-A-A-B-B in the southern areas of Zhejiang province. Multiple genotypes co-circulated during five RSV epidemic seasons. NA1 and BA9 genotypes were the predominant genotypes of subtype A and B, respectively. Compared with infection with BA9 genotype, NA1 genotype infection was associated with more severe disease and proportion of patients needed oxygen therapy was higher.

Child, Preschool ; China ; epidemiology ; Genotype ; Hospitalization ; Humans ; Infant ; Nasopharynx ; Phylogeny ; Polymerase Chain Reaction ; Respiratory Syncytial Virus Infections ; epidemiology ; Respiratory Syncytial Virus, Human ; genetics ; Respiratory Tract Infections ; epidemiology ; Seasons

Objective: To understand the detection rate, epidemic pattern of respiratory syncytial virus (RSV) in hospitalized children with acute lower respiratory tract infection (ALRTI) in China. Methods: From June 2017 to March 2020, a prospective multi-center study on the viral aetiology among hospitalized children with ALRTI was conducted in six pediatrics hospital of North China, Northeast, Northwest, South China, Southeast, and Southwest China. A total of 2 839 hospitalized children with ALRTI were enrolled, and the respiratory specimens were collected from these cases. A multiplex real-time RT-PCR assay were employed to screen the respiratory viruses, and the molecular epidemiological and clinical characteristics of children infected with RSV were analyzed. Results: The positve rate of RSV was 18.6% (528/2 839), and the positive rate of RSV in different regions ranged from 5.5% to 44.3%. The positive rate of RSV in male was higher than that in female (20.2% vs 16.3%), and there was a significant statistically difference between two groups (χ2=6.74, P=0.009). The positive rate of RSV among children under 5 years old was higher than that among children older than 5 years old (22.3% vs 4.5%), and there was a significant statistically difference between two groups (χ2=97.98,P<0.001). The positive rate of RSV among the <6 months age group was higher than that of other age groups (all P<0.05). During January 2018 and December 2019, RSV was detected in almost all through the year, and showed peaks in winter and spring. RSV-positive cases accounted for 17.0% (46/270) among children with severe pneumonia, including 36 cases infected with RSV alone. Conclusion: RSV is an important viral pathogen in children under 5 years old with ALRTI in China. The virus can be detected almost all through the year and reached the peak in winter and spring. RSV could lead to severe pneumonia in children and caused huge threaten to children's health.
Child ; Humans ; Male ; Female ; Infant ; Child, Preschool ; Respiratory Syncytial Virus Infections/epidemiology* ; Child, Hospitalized ; Prospective Studies ; Respiratory Tract Infections/epidemiology* ; Respiratory Syncytial Virus, Human ; China/epidemiology*

OBJECTIVE: To study the detection rate, epidemic pattern, and clinical features of respiratory syncytial virus (RSV) in hospitalized children with acute lower respiratory infection (ALRI). METHODS: Nasopharyngeal aspirates were collected from children with ALRI, aged < 2 years, who were hospitalized in Children's Hospital of Chongqing Medical University from June 2013 to May 2018. Multiplex PCR was used to detect 16 common respiratory viruses. The epidemiological characteristics of RSV were analyzed. RESULTS: A total of 2 066 hospitalized children with ALRI were enrolled. Among the children, 1 595 (77.20%) tested positive for virus and 826 (39.98%) tested positive for RSV [410(49.6%) positive for RSV-A, 414 (50.1%) positive for RSV-B, and 2 (0.2%) positive for both RSV-A and RSV-B]. RSV-B was the main subtype detected in 2013-2014 and 2016-2017, while RSV-A was the main subtype in 2014-2015 and 2017-2018, and these two subtypes were prevalent in 2015-2016. The highest detection rate of RSV was noted in winter. RSV + human rhinovirus was the most common combination of viruses and was detected in 123 children. These children were more likely to develop wheezing than those with single RSV detected ( CONCLUSIONS In Chongqing in 2013-2018, RSV-A and RSV-B not only can predominate alternately, but also can co-circulate during a season. RSV is the major viral pathogen of hospitalized children with ALRI and can cause severe lower respiratory tract infection. There are no differences in clinical manifestations between children with RSV-A infection and those with RSV-B infection, but boys are more susceptible to RSV-A infection.
Child ; Child, Hospitalized ; Child, Preschool ; China/epidemiology* ; Female ; Humans ; Infant ; Male ; Respiratory Syncytial Virus Infections/epidemiology* ; Respiratory Syncytial Virus, Human ; Respiratory Tract Infections/epidemiology*

OBJECTIVETo investigate human coronaviruses (HCoVs) infection in children with acute lower respiratory tract infection(ALRTI)and to explore the clinical features of ALRTI caused by HCoVs in children.

METHODTotally 4 371 children with clinical diagnosis of ALRTI during the period from March 2007 to February 2015 seen in Beijing Children's Hospital were recruited into this study. Patients were divided into 4 groups by age, including 1 890 cases in < 1 year group, 788 cases in 1-3 years group, 553 cases in 3-6 years group, 1140 cases in ≥6 years group. One nasopharyngeal aspirate specimen was collected from each patient. RT-PCR methods were applied to detect 9 common respiratory viruses including HCoVs (including HCoV-OC43, HCoV-229E, HCoV-NL63 and HCoV-HKU1), respiratory syncytial virus (RSV) and so on. Clinical features of ALRTI with single HCoVs infection were analyzed and compared with hospitalized ALRTI cases with single RSV infection in the same period.

RESULT(1) Totally 2 895 cases were positive for at least one virus in this study in 4 371 ALRTI patients (positive rate 66.23%), in which 147 cases were positive for HCoVs infection (positive rate 3.36%). (2) Positive rates of HCoVs in each year from 2007 to 2014 were 6.11%, 3.79%, 4.69%, 4.31%, 2.38% 2.10%, 0.77% and 2.65%, respectively. The mean positive rates of HCoVs for each month from January to December were 2.53%, 2.12%, 3.63%, 6.68%, 1.53%, 3.77%, 3.92%, 3.00%, 2.15%, 5.26%, 3.01% and 2.80%. (3) Detection results of each subtypes of HCoVs in total 4 371 pediatric ALRTI patients were: 48 cases positive for HCoV-OC43(1.10%), 32 cases positive for HCoV-229E(0.73%), 25 cases positive for HCoV-NL63 (0.57%), 27 cases positive for HCoV-HKU1 (0.62%). (4) Positive rates of HCoVs infection in <1 year group, 1-3 years group, 3-6 years group and ≥ 6 years group were 4.13%, 5.08%, 2.71% and 1.23%, respectively. There were significant differences in positive rates of HCoV among groups (χ² = 27.218, P<0.01). (5) There were 16 hospitalized cases with single infection of HCoVs in this study, of which 12 cases were diagnosed as bronchopneumonia, 3 cases developed acute laryngeal obstruction, 2 cases had acute bronchial asthma attack. Common clinical manifestations included cough (14 cases), gasping (13 cases), dyspnea (9 cases), fever (6 cases), hoarseness (4 cases), laryngeal stridor (4 cases) and abnormality on chest X-ray (including fuzzy lung texture, patchy shadow and consolidation) (12 cases). (6) There were no significant differences in the incidence of clinical manifestations (including cough, gasping, dyspnea, fever and abnormality on chest X-ray), complications (including respiratory failure, myocardial damage, and acute bronchial asthma attack) and mechanical ventilation between hospitalized ALRTI patients with single HCoV infection and 193 patients with single RSV infection in the same period.

CONCLUSIONHCoVs are pathogens of ALRTI in children, The overall positive rate of HCoVs was 3.36% in this study. The clinical manifestations and severity of ALRTI caused by single HCoVs was comparable to that of ALRTI with single RSV infection in children.

Acute Disease ; Beijing ; Child ; Child, Preschool ; Coronavirus ; Coronavirus Infections ; epidemiology ; Humans ; Incidence ; Infant ; Respiratory Syncytial Virus Infections ; epidemiology ; Respiratory Syncytial Viruses ; Respiratory Tract Infections ; epidemiology ; virology

OBJECTIVETo probe the epidemiological trend of respiratory syncytial virus (RSV) and cellular immunological change of RSV bronchopneumonia among children in Suzhou in the past five years.

METHODS10,205 children with acute respiratory tract infection from January 2001 to December 2005 were enrolled into the study. Nasopharyngeal aspirates were obtained from the respiratory tract by aseptic vacuum aspiration. Direct immuno-fluorescence assay was employed to detect seven kinds of virus antigens including RSV antigen. CD3, CD4, CD8, CD19, CD16 and CD56 in peripheral blood mononuclear cells of 30 patients with RSV bronchopneumonia (1.5-24.0 months old group) were analyzed by flow cytometry analysis, and 15 normal infants (1.5-24.0 months old group) were enrolled as control group.

RESULTSThe annual positive rate of RSV was 24.94%, 25.83%, 24.05%, 25.39% and 27.30% respectively from 2001 to 2005. It also found that the peak season for RSV infection was spring or winter (January to March or November to December). The positive rate of RSV was significantly higher in 1-12 months old group than that in > 12 months old group (chi2 = 97.320, P < 0.01), as well as the groups between 1-12 months old (chi2 = 7.804, P < 0.05, the highest positive rate was occurred at 3-6 months old group). The positive rate of RSV was significantly higher in boys than that in girls (chi2 = 9.693, P < 0.01). The percentages of CD3+, CD4+, CD8+ and NK (CD16 + 56)+ cells were significantly lower in RSV bronchopneumonia than those in control group (t = 3.199, P < 0.01; t = 2.215, P < 0.05; t = 2.619, P < 0.05 and t = 5.240, P < 0.01, respectively). While the percentage of CD19+ cells was significantly elevated in RSV bronchopneumonia than that in control group (t = 2.875, P < 0.01).

CONCLUSIONRSV infection is of obvious seasonal changes. The younger the patient, the higher positive rates of RSV infection is, while and the cellular immunity function is lower. The effective measures for preventing RSV infection are important, especially for the infants. Further investigation is necessary to understand the causes of the variations for RSV infections between boys and girls.

Adolescent ; Bronchopneumonia ; epidemiology ; immunology ; virology ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Respiratory Syncytial Virus Infections ; epidemiology ; immunology ; Respiratory Syncytial Viruses

OBJECTIVETo investigate the infection status and epidemiological characteristics of influenza virus and respiratory syncytial virus (RSV) in influenza-like illness (ILI) of children ( ≤ 14 years) in Wuhan area from 2008 to 2012.

METHODSA total of 2854 cases of ILI patients ( ≤ 14 years) in a hospital of Wuhan were recruited in the study from July 2008 to June 2012. The sample of pharyngeal swab was collected from each patient, to extract the virus nucleic acids. Real-time fluorescent quantitation reverse transcription PCR (RT-PCR) method was applied to detect the subtypes of influenza virus and RSV, and then analyzed the time and age characteristics.

RESULTSOut of the 2854 cases, 758 (26.6%) were positive for influenza virus,including 547 (19.2%) influenza A virus positive samples and 211 (7.4%) influenza B virus positive samples. Usually, there were two peaks present in the annual curve of influenza virus, namely summer peak and winter/spring peak. The positive rate of influenza virus in 6-14 years old children (48.0%, 275/573) was significantly higher than that in 3-5 years old children (26.6%, 213/801) and that under 3 years old children (18.3%, 270/1480). The difference showed statistical significance (χ(2) = 187.432, P < 0.01). A total of 219 (7.7%) cases were positive for RSV,including 108 RSV-A positive samples and 112 RSV-B positive samples (1 co-infection). The epidemic of RSV showed an obvious seasonal pattern with peaks in autumn,winter and spring,which accounted for 96.8% (212/219) of all the cases; however, the annual incidence of RSV fluctuated greatly. The predominant subtype shifted every 2 years. RSV-B predominated during September 2008 and May 2009, December 2009 and March 2010, accounting for 76.6% (36/47) and 96.9% (62/64) respectively. RSV-A predominated during November 2010 and March 2011, September 2011 and April 2012, accounting for 92.5% (37/40) and 100.0% (48/48) respectively. With the increase of the age, the positive rate of RSV-A and RSV-B decreased gradually (RSV-A: χ(2) = 36.223, P < 0.01; RSV-B: χ(2) = 36.281, P < 0.01). The positive rates of RSV-A in children < 1,1,2,3,4,5-9 and 10-14 years old were 7.0% (26/373), 5.9% (39/662), 4.0% (18/445), 3.2% (13/406), 1.3% (3/236), 1.4% (7/517) and 0.9% (2/215) respectively; while, the positive rates of RSV-B in each age group were 6.4% (24/373), 6.0% (40/662), 4.5% (20/445), 4.4% (18/406), 1.3% (3/236), 1.0% (5/517) and 0.9% (2/215) respectively. The children aged 0-3 years old were more susceptible for RSV infection,accounting for 90.0% (197/219) of the total positive samples. During the outbreak of influenza A H1N1 in November 2009, the positive rate of RSW was 3.0% (3/100), lower than that in the same month of 2008, 2010 and 2011,which were separately 18.2% (6/33), 10.8% (10/93) and 10.0% (4/40). The difference showed statistical significance (χ(2) = 8.450, P < 0.05). During the outbreak of influenza A (H1N1) in January 2011,the positive rate of RSV was 5.7% (3/53), lower than those in the same month of 2009, 2010 and 2012, which was separately 21.7% (5/23), 28.6% (22/77) and 16.0% (8/50). The difference showed statistical significance (χ(2) = 11.233,P < 0.05). During the period of less influenza happened in September 2011, the RSV positive rate was 25.0% (10/40), higher than those in the same month of 2008, 2009 and 2010, which was separately 11.4% (4/35), 1.7% (2/118) and 0.0% (0/109). The difference showed statistical significance (χ(2) = 32.521, P < 0.01).

CONCLUSIONBoth influenza virus and RSV were important etiological agents of ILI of children in Wuhan. The characteristics of seasonal and age distributions of the two viruses were notably different; meanwhile, a certain inhibitional effect of influenza virus on RSV could be observed.

Adolescent ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Influenza, Human ; epidemiology ; Male ; Orthomyxoviridae ; classification ; isolation & purification ; Respiratory Syncytial Virus Infections ; epidemiology ; Respiratory Syncytial Viruses ; classification ; isolation & purification