Key result
Zambian G2P[4] rotavirus strains show >97% nucleotide similarity and positive selection in Viral Protein 3.
Why the study?
Reports of immediate upsurges of G2P[4] rotavirus following vaccination raised concern about suboptimal vaccine effectiveness against this genotype in the long term.
Observational (n=29)
Genomic analysis of Zambian G2P[4] rotavirus strains reveals positive selection at amino acid site 7 in VP3, suggesting a potential mechanism for surviving immune pressure post-vaccination.
The G2P[4] genotype is among the rotavirus strains that circulate commonly in humans. Several countries have reported its immediate upsurge after the introduction of rotavirus vaccination, raising concern about sub-optimal vaccine effectiveness against this genotype in the long term. This study aimed to gain insight into the evolution of post-vaccine Zambian G2P[4] group A rotavirus (RVA) strains and their overall genetic make-up by analysis of sequence alignments at the amino acid (AA) level. Twenty-nine Zambian G2P[4] rotavirus strains were subjected to whole-genome sequencing using the Illumina MiSeq® platform. All the strains exhibited the typical DS-1-like genotype constellation, and the nucleotide sequences of the 11 genome segments showed high nucleotide similarities (>97%). Phylogenetic analyses together with representative global G2P[4] RVA showed that Zambian strains clustered into human lineages IV (for VP2, VP4, VP7, NSP1, and NSP5), V (for VP1, VP3, VP6, NSP2, and NSP3), and XXIII (for NSP4). The AA differences between the lineages where the study strains clustered and lineages of global reference strains were identified and analyzed. Selection pressure analysis revealed that AA site seven in the Viral Protein 3 (VP3) genome segment was under positive selection. This site occurs in the region of intrinsic disorder in the VP3 protein, and Zambian G2P[4] strains could potentially be utilizing this intrinsically disordered region to survive immune pressure. The Zambian G2P[4] strains from 2012 to 2016 comprised the G2P[4] strains that have been circulating globally since the early 2000s, highlighting the epidemiological fitness of these contemporary G2P[4] strains. Continuous whole-genome surveillance of G2P[4] strains remains imperative to understand their evolution during the post-vaccination period.
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Mwangi et al. (2023) conducted an observational in G2P[4] group A rotavirus (n=29). Whole-genome sequencing vs. Global reference strains was evaluated on Evolution and genetic make-up by analysis of sequence alignments at the amino acid level. Genomic analysis of 29 Zambian G2P[4] rotavirus strains revealed high nucleotide similarities (>97%) and positive selection at amino acid site 7 in the Viral Protein 3 genome segment.
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