title: High frequency of repeated infections due to emerging genotypes of human respiratory syncytial viruses among children during eight successive epidemic seasons in Japan.
abstract: In eight successive seasons (2001 to 2009), a total of 726 human respiratory syncytial virus (HRSV) infections from a total of 1,560 children with acute lower respiratory tract illness were identified. Molecular analysis of the attachment (G) protein gene confirmed that 52 (7.8%) children were infected more than once with any of the 3 genotypes of HRSV-A (genotypes GA5, NA1, and NA2) and/or 6 genotypes of HRSV-B (genotypes BA4, BA5, and BA7 to BA10). Repeated infections in 46 cases (82.1%) occurred in the next season, and only one case occurred in the same season (10-day interval). First infections were 33 (63.5%) HRSV-A cases and 19 (36.5%) HRSV-B cases, whereas second infections occurred in 35 (67.3%) HRSV-A cases and 17 (32.7%) HRSV-B cases. Third infections were attributed to 4 (100.0%) HRSV-A cases. Homologous subgroup reinfections were detected in 28 cases, 23 HRSV-A cases and 5 HRSV-B cases (P = 0.005), whereas homologous genotype reinfections were detected only for 5 HRSV-A cases (2GA5 and 3NA2) but not any HRSV-B case. Heterologous subgroup reinfections were detected in 28 cases, 12 cases from HRSV-A-to-HRSV-B reinfections and 16 cases from HRSV-B-to-HRSV-A reinfections. Genotypes NA1 and NA2 had higher numbers of heterologous genotype infections than did other genotypes. Our observations suggest that repeated infections occur more frequently in HRSV-A strains than in HRSV-B strains, and heterologous genotype reinfections occur more frequently than homologous genotype reinfections, especially in the case of the emerging genotypes NA1 and NA2 of HRSV-A strains that circulated in the community during our study period.
authors.affiliation: Division of Public Health, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-Dori, Niigata Prefecture 951-8510, Niigata City, Japan. gucci@med.niigata-u.ac.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Sano
authors.forename: Isolde C
authors.initials: IC
authors.lastname: Dapat
authors.forename: Reiko
authors.initials: R
authors.lastname: Saito
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kumaki
authors.forename: Yugo
authors.initials: Y
authors.lastname: Shobugawa
authors.forename: Clyde
authors.initials: C
authors.lastname: Dapat
authors.forename: Makoto
authors.initials: M
authors.lastname: Uchiyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007564:Japan / Q000453:epidemiology; D008297:Male; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012367:RNA, Viral / Q000235:genetics; D012008:Recurrence; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology* / Q000821:virology*; D018113:Respiratory Syncytial Virus, Human / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000821:virology; D017422:Sequence Analysis, DNA; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D012367:RNA, Viral; D014759:Viral Envelope Proteins; C116204:attachment protein G