Objective:A genome-wide molecular characterization of FJ21351116, a strain of G3P[8]-E2 2021 collected in Fujian, China, was performed.Methods:Whole genome sequencing of FJ21351116 was performed using a high-sensitivity group A rotavirus whole genome sequencing method. Genomic characteriza-tion of the virus was assessed by nucleic acid sequence analysis using MEGA 11.0, Geneious 9.0.2 and DNASTAR software. Neutralization epitopes of VP7 and VP4 (VP8*) were analyzed using BioEdit v. 7.0.9.0 and PyMOL v. 2.5.2.Results:In this study, FJ21351116 was shown to be a G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 genotype, and the result of phylogenetic tree showed that the VP7, VP4, VP3, and NSP2-NSP5 genes of the FJ21351116 strain were related to the equine-like DS-1-like G3P[8] genes that have been detected in Japan in recent years. VP6, VP1, VP2, and NSP1 genes are closely related to G2P[4] in most countries, especially in Singapore, suggesting that this strain was formed by genetic reassortment during the evolution of equine-like G3P[8] and G2P[4]. Evolutionary relationships between the VP7/VP4 genes of FJ21351116 and Rotarix and RotaTeq vaccines suggest that the multiple mutations in both VP7 and VP4 (VP8*) neutralizing antigenic epitopes and vaccine amino acid sites. It is hypothesized that the Rotarix and RotaTeq vaccines may be less effective against equine DS-1-like G3P[8] RVA, and the sequence differences with Rotarix are higher than those with RotaTeq.Conclusions:In this study, we found a rare case of DS-1-like G3P [8] RVA strain in China. Currently, horse-like DS-1-like G3P [8] RVA is relatively rare in China and may be poorly protected by vaccine strains, emphasizing the importance of continuous monitoring of RVA strains and the development of efficient and full-coverage RVA vaccines.

Rotavirus is one of the most common pathogens causing severe gastroenteritis in children under 5 years of age in the world. RV vaccination is the most effective measure to control rotavirus diarrhea in infants. The immune effect of RV vaccine is different in countries with different income levels. In this study, the factors affecting the immune effect of RV vaccine are systematically expounded, which provides reference for the research of RV vaccine and the formulation of immune strategy.