IntroductionRotavirus vaccination with the live-attenuated monovalent (a G1P[8] 
human rotavirus strain) two-dose Rotarix vaccine was introduced in England in 
July 2013. Since then, there have been significant reductions in rotavirus 
gastroenteritis incidence.AimWe assessed the vaccine's impact on rotavirus 
genotype distribution and diversity 3 years post-vaccine 
introduction.MethodsEpidemiological and microbiological data on genotyped 
rotavirus-positive samples between September 2006 and August 2016 were supplied 
by EuroRotaNet and Public Health England. Multinomial multivariable logistic 
regression adjusting for year, season and age was used to quantify changes in 
genotype prevalence in the vaccine period. Genotype diversity was measured using 
the Shannon's index (H') and Simpson's index of diversity (D).ResultsWe analysed 
genotypes from 8,044 faecal samples. In the pre-vaccine era, G1P[8] was most 
prevalent, ranging from 39% (411/1,057) to 74% (527/709) per year. In the 
vaccine era, G1P[8] prevalence declined each season (35%, 231/654; 12%, 
154/1,257; 5%, 34/726) and genotype diversity increased significantly in 6-59 
months old children (H' p < 0.001: D p < 0.001). In multinomial analysis, G2P[4] 
(adjusted multinomial odds ratio (aMOR): 9.51; 95% confidence interval (CI): 
7.02-12.90), G3P[8] (aMOR: 2.83; 95% CI: 2.17-3.81), G12P[8] (aMOR: 2.46; 95% 
CI: 1.62-3.73) and G4P[8] (aMOR: 1.42; 95% CI: 1.02-1.96) significantly 
increased relative to G1P[8].ConclusionsIn the context of reduced rotavirus 
disease incidence, genotype diversity has increased, with a relative change in 
the dominant genotype from G1P[8] to G2P[4] after vaccine introduction. These 
changes will need continued surveillance as the number and age of vaccinated 
birth cohorts increase in the future.