Sheikh Ariful Hoque1, Nusrat Khandoker2, Aksara Thongprachum3, Pattara Khamrin4, Sayaka Takanashi5, Shoko Okitsu6, Shuichi Nishimura2, Hideaki Kikuta2, Atsuko Yamamoto2, Kumiko Sugita2, Tsuneyoshi Baba2, Masaaki Kobayashi2, Satoshi Hayakawa2, Masashi Mizuguchi5, Niwat Maneekarn7, Hiroshi Ushijima8. 1. Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan; Cell and Tissue Culture Laboratory, Centre for Advanced Research in Sciences (CARS), University of Dhaka, Dhaka, Bangladesh. 2. Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan. 3. Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan; Faculty of Public Health, Chiang Mai University, Thailand. 4. Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan; Department of Microbiology, Faculty of Medicine, Chiang Mai University, Thailand. 5. Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. 6. Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan; Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. 7. Department of Microbiology, Faculty of Medicine, Chiang Mai University, Thailand. 8. Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan; Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. Electronic address: ushijima-hiroshi@jcom.home.ne.jp.
Abstract
BACKGROUND: Diversity in group A rotavirus (RVA) strains after introduction of RV-vaccines remains an emerging concern worldwide. In this study, we investigated the prevalence and distribution of RVA genotypes in Japanese children with acute gastroenteritis (AGE) from 2015 to 2018. In addition, a comparison of the genotypes in pre-vaccination (2006-2012) and post-vaccination (2012-2018) periods was conducted to understand the impact of these vaccines on genotype distribution. METHODS: Fecal samples were collected regularly from outpatient clinics in six localities: Hokkaido, Tokyo, Shizuoka, Osaka, Kyoto, and Saga. RVA were screened and genotyped by RT-PCR and sequence-based genotyping. RESULTS: During the period 2015-2018, RVA was detected in 307 (19.7%) samples out of 1557 specimens: 29.9% (95% CI: 25.8% to 34.3%), 17.9% (95% CI: 14.7% to 21.5%), and 13% (95% CI: 10.3% to 16.0%) were detected RVA-positive in 2015-2016, 2016-2017 and 2017-2018, respectively. The average detection of RVA in pre-vaccination (2006-2012) and post-vaccination (2012-2018) era remained almost similar (18%-20%). The G2P[4]I2 (52.1%, 95% CI: 43.5%-60.6%) remained the most common genotype in 2015-2016, whereas G8P[8]I2 (55.9%, 95% CI: 45.2%-66.2%) dominated in 2016-2017. In 2017-2018, G9P[8]I2 (42.0%, 95% CI: 30.5%-53.9%) prevailed, followed by G9P[8]I1 (23.0%, 95% CI: 14.0%-34.2%). The detection rate of some common genotypes of pre-vaccination era like G1P[8] and G3P[8] has been reduced after introduction of RV-vaccine, whereas genotypes that were sporadic before the introduction of vaccines like G2P[4], G2P[8], G9P[8] and G8P[8] were emerged/reemerged in post-vaccination period. CONCLUSIONS: Our study presented the diversity in circulating RVA genotypes in Japan before and after introduction of RV-vaccines. Sudden emergence of DS-1-like (I2) unusual strains in post-vaccination era remains alarming. Continuous monitoring of RVA genotypes is therefore indispensable to refine future vaccine strategy.
BACKGROUND: Diversity in group A rotavirus (RVA) strains after introduction of RV-vaccines remains an emerging concern worldwide. In this study, we investigated the prevalence and distribution of RVA genotypes in Japanese children with acute gastroenteritis (AGE) from 2015 to 2018. In addition, a comparison of the genotypes in pre-vaccination (2006-2012) and post-vaccination (2012-2018) periods was conducted to understand the impact of these vaccines on genotype distribution. METHODS: Fecal samples were collected regularly from outpatient clinics in six localities: Hokkaido, Tokyo, Shizuoka, Osaka, Kyoto, and Saga. RVA were screened and genotyped by RT-PCR and sequence-based genotyping. RESULTS: During the period 2015-2018, RVA was detected in 307 (19.7%) samples out of 1557 specimens: 29.9% (95% CI: 25.8% to 34.3%), 17.9% (95% CI: 14.7% to 21.5%), and 13% (95% CI: 10.3% to 16.0%) were detected RVA-positive in 2015-2016, 2016-2017 and 2017-2018, respectively. The average detection of RVA in pre-vaccination (2006-2012) and post-vaccination (2012-2018) era remained almost similar (18%-20%). The G2P[4]I2 (52.1%, 95% CI: 43.5%-60.6%) remained the most common genotype in 2015-2016, whereas G8P[8]I2 (55.9%, 95% CI: 45.2%-66.2%) dominated in 2016-2017. In 2017-2018, G9P[8]I2 (42.0%, 95% CI: 30.5%-53.9%) prevailed, followed by G9P[8]I1 (23.0%, 95% CI: 14.0%-34.2%). The detection rate of some common genotypes of pre-vaccination era like G1P[8] and G3P[8] has been reduced after introduction of RV-vaccine, whereas genotypes that were sporadic before the introduction of vaccines like G2P[4], G2P[8], G9P[8] and G8P[8] were emerged/reemerged in post-vaccination period. CONCLUSIONS: Our study presented the diversity in circulating RVA genotypes in Japan before and after introduction of RV-vaccines. Sudden emergence of DS-1-like (I2) unusual strains in post-vaccination era remains alarming. Continuous monitoring of RVA genotypes is therefore indispensable to refine future vaccine strategy.