Impact of rotavirus vaccination on rotavirus genotype distribution and diversity in England, September 2006 to August 2016

Abstract

Introduction Rotavirus 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. Aim We assessed the vaccine’s impact on rotavirus genotype distribution and diversity 3 years post-vaccine introduction. Methods Epidemiological 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). Results We 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]. Conclusions In 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.

Molecular Characteristics of Novel Mono-Reassortant G9P[8] Rotavirus A Strains Possessing the NSP4 Gene of the E2 Genotype Detected in Tokyo, Japan

“…In 2017, G2P [4] (40.0 ) was the most prevalent strain, followed by G3P [8] (DS-1-like) (28.0 ), G8P [8] (10.0 ), G3P [8] (Wa-like) (8.0 ), G9P [8]-E1 (8.0 ), and mixed infection (6.0 ). In 2018, G3P [8] (DS-1-like) (28.6 ) and G9P [8]-E2 (28.6 ) were the most prevalent strains, followed by G9P [8]-E1 (19.0 ), G2P [4] (9.5 ), G8P [8] (9.5 ), and mixed infection (4.8 ). Six G9P [8]-E2 strains detected in 2018 showed an atypical genotype constellation (G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1), which had not been reported previously.…”

“…In 2018, G3P [8] (DS-1-like) (28.6 ) and G9P [8]-E2 (28.6 ) were the most prevalent strains, followed by G9P [8]-E1 (19.0 ), G2P [4] (9.5 ), G8P [8] (9.5 ), and mixed infection (4.8 ). Six G9P [8]-E2 strains detected in 2018 showed an atypical genotype constellation (G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1), which had not been reported previously. Phylogenetic analyses suggested that the RVA virus was generated by inter-genogroup reassortment between commonly circulating G9P [8] and G2P [4] strains in Japan.…”

“…Phylogenetic analyses suggested that the RVA virus was generated by inter-genogroup reassortment between commonly circulating G9P [8] and G2P [4] strains in Japan. The G9P [8] strain seemed to be reassorted with only the NSP4 gene of the E2 genotype of the G2P [4] strain. Since this newly-emerged G9P [8]-E2 virus was detected in different locations in Tokyo, the virus appears to have already begun to spread to a wider area.…”

“…Human RVAs have largely been classified into two genogroups based on genotype constellations (15). The Wa and DS-1 genogroups are described as G1-P [8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 and G2-P [4]-I2-R2-C2-M2-A2-N2-T2-E2-H2, respectively (12)(13)(14). G1, G3, G4, G9, and G12 viruses are usually grouped into the Wa-like genotype constellation, and most G2 and G8 viruses are grouped into the DS-1-like genotype constellation (16).…”

“…G1, G3, G4, G9, and G12 viruses are usually grouped into the Wa-like genotype constellation, and most G2 and G8 viruses are grouped into the DS-1-like genotype constellation (16). However, unusual RVAs such as DS-1-like G1P [8] viruses (G1-P [8]-I2-R2-C2-M2-A2-N2-T2-E2-H2) (17)(18)(19)(20)(21) and DS-1-like (equinelike) G3P [8] viruses (G3-P [8]-I2-R2-C2-M2-A2-N2-T2-E2-H2) (22)(23)(24)(25)(26) were recently detected, and have begun to spread worldwide. In Japan, DS-1-like G1P [8] viruses were circulating in 2012-15 (17)(18)(19), and DS-1-like G3P [8] viruses have been circulating since 2015 (25,27).…”