High Frequency of Repeated Infections Due to Emerging Genotypes of Human Respiratory Syncytial Viruses among Children during Eight Successive Epidemic Seasons in Japan

• Published in: Journal of Clinical Microbiology 2011-03, Vol.49 (3), p.1034-1040
• Main Authors: Yamaguchi, Masahiro, Sano, Yasuko, Dapat, Isolde C, Saito, Reiko, Suzuki, Yasushi, Kumaki, Akihiko, Shobugawa, Yugo, Dapat, Clyde, Uchiyama, Makoto, Suzuki, Hiroshi
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Child, Preschool; Epidemiology; Female; Fundamental and applied biological sciences. Psychology; Genotype; Human respiratory syncytial virus; Humans; Infant; Japan - epidemiology; Male; Microbiology; Molecular Sequence Data; Polymorphism, Genetic; Recurrence; Respiratory Syncytial Virus Infections - epidemiology; Respiratory Syncytial Virus Infections - virology; Respiratory Syncytial Virus, Human - classification; Respiratory Syncytial Virus, Human - genetics; Respiratory Syncytial Virus, Human - isolation & purification; Respiratory Tract Infections - epidemiology; Respiratory Tract Infections - virology; RNA, Viral - genetics; Sequence Analysis, DNA; Viral Envelope Proteins - genetics
• ISSN: 0095-1137; 1098-660X
• DOI: 10.1128/jcm.02132-10

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.