Whole-Genome Analysis of G2P[4] Rotavirus Strains in China in 2022 and Comparison of Their Antigenic Epitopes with Vaccine Strains.

Group A rotavirus (RVA) is the leading cause of acute gastroenteritis in infants and young children worldwide. To elucidate the molecular epidemiology of G2P[4] rotavirus in China and the protective effects of vaccines, whole-genome analysis of 13 G2P[4] RVA strains collected from China in 2022 was performed. Twelve strains possessed the typical DS-1-like genome constellation G2-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2. Only GS2265 possessed the genome constellation G2-P[4]-12-R2-C2-M2-A2-N2-T2-E1-H2. With the exception of the NSP4 segment of GS2265, all other sequences of the 13 G2P[4] RVA strains clustered within the same lineage on phylogenetic analysis. However, QD2210 and SX2205 were grouped into different branches compared to the other strains. In the VP7 antigenic epitopes, four residues differed from the RotaTeq G2 strain; specifically, A87T and D96N in the 7-1a region and S213D and S242N in the 7-1b region. Comparison of the current G2P[4] RVA strains circulating in China with those circulating globally revealed a high degree of sequence identity. High genetic variability among the newly characterized G2P[4] RVA strains suggest the strains evolve fast. Finally, our data suggest that the multivalent RotaTeq vaccine could have provided better protection than the monovalent Rotarix and LLR.