Authors: L P Do Y H Doan T Nakagomi M Kaneko P Gauchan C T Ngo M B Nguyen T Yamashiro A D Dang O Nakagomi
Publish Date: 2015/12/28
Volume: 161, Issue: 4, Pages: 833-850
Abstract
Rotavirus vaccines work better in developed countries than in developing countries leading to the question of whether the circulating strains are different in these two settings In 2008 a clinical trial of the pentavalent rotavirus vaccine was performed in Nha Trang Vietnam in which the efficacy was reported to be 64 Although samples were collected independently from the clinical trial we examined faecal specimens from children hospitalised for rotavirus diarrhoea and found that G3P8 and G1P8 were codominant at the time of the clinical trial The aim of this study was to explore whether they were divergent from the strains circulating in the developed countries where the vaccine efficacy is high Two G3P8 and two G1P8 strains that were regarded as representatives based on their electropherotypes were selected for fullgenome sequencing The genotype constellation was G1/G3P8I1R1C1M1A1N1T1E1H1 All but the VP4 genes one of which belonged to the emerging P8b genotype OP354like VP4 clustered into one or more lineages/alleles with the strains circulating in developed countries with ≥975 nucleotide sequence identity Additionally 10 G1 and 12 G3 VP7 sequences as well as 31 VP4 sequences were determined No amino acid differences were observed between the Vietnamese strains and strains in the developed countries that were likely to have affected the neutralisation specificity of their VP7 and VP4 In conclusion apart from prevalent P8b VP4 virtually no differences were observed between the predominant strains circulating in Vietnam at the time of the clinical trial and the strains in the developed countries hence the lower vaccine efficacy was more likely to be due to factors other than strain divergenceThis study was in part supported by Grantsinaid for scientific research from the Ministry of Health Labour and Welfare of Japan as well as a Grant from Japan Initiative for Global Research Network on Infectious Diseases from Japan Agency for Medical Research and Development AMED
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