Genetic heterogeneity of group A rotaviruses: a review of the evolutionary dynamics and implication on vaccination

ABSTRACT

Introduction

Human rotavirus remains a major etiology of acute gastroenteritis among under 5-year children worldwide despite the availability of oral vaccines. The genetic instability of rotavirus and the ability to form different combinations from the different G- and P-types reshapes the antigenic landscape of emerging strains which often display limited or no antigen identities with the vaccine strain. As evidence also suggests, the selection of the antigenically distinct novel or rare strains and their successful spread in the human population has raised concerns regarding undermining the effectiveness of vaccination programs.

Areas covered

We review aspects related to current knowledge about genetic and antigenic heterogeneity of rotavirus, the mechanism of genetic diversity and evolution, and the implication of genetic change on vaccination.

Expert opinion

Genetic changes in the segmented genome of rotavirus can alter the antigenic landscape on the virion capsid and further promote viral fitness in a fully vaccinated population. Against this background, the potential risk of the appearance of new rotavirus strains over the long term would be better predicted by a continued and increased close monitoring of the variants across the globe to identify any change associated with disease dynamics.

KEYWORDS:

• Diversity
• evolution
• heterogeneity
• rotavirus
• vaccine

Article highlights

• Natural changes in rotavirus and evolutionary drivers (point mutations, genome segment reassortment, genome segment recombination including genome rearrangements, cross-species transmission) perpetrate the antigenic and genetic heterogeneity of group A rotavirus.

• Recent advances in rotavirus typing involving whole genome sequencing studies for the classification of rotaviruses have aided in the study and understanding of epidemiological and evolutionary pattern of rotavirus.

• Over a decade, vaccination has represented the primary strategy for the control of diarrheic burden due to rotavirus globally. As of March 2022, at least, one of the four rotavirus A vaccines (Rotarix, RotaTeq, ROTAVAC, and Rotasiil) have been introduced by 108 countries in their expanded childhood immunization programs.

• There are increasing reports of rotavirus vaccine underperformance in concert with antigenic diversity of rotaviruses in the licensure area, particularly in countries of low socio-economic conditions.

• The post-licensure era has witnessed the emergence of antigenically distinct novel or rare strains of rotavirus which have successfully spread in the human population, particularly in the developing countries, causing sporadic and epidemic gastroenteritis.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

CA Omatola and AO Olaniran were involved in the conceptualization, manuscript writing and approval of the final draft.

Additional information

Funding

This paper was not funded.