Characterization of Rotavirus Strains Responsible for Breakthrough Diarrheal Diseases among Zambian Children Using...

Area of Science:

• Virology
• Immunology
• Public Health

Background:

• Rotavirus (RV) infection remains a significant cause of diarrheal disease globally, particularly in high-burden settings.
• Breakthrough RV infections in vaccinated children highlight the challenge of vaccine efficacy against evolving viral strains.
• Limited characterization of RV strains causing breakthrough infections in resource-limited countries hinders effective disease control.

Purpose of the Study:

• To characterize the genetic makeup of rotavirus strains detected in fully vaccinated children in Zambia.
• To investigate potential immune evasion mechanisms of these breakthrough RV strains.

Main Methods:

• Whole genome sequencing of rotavirus strains from diarrheal stool specimens using Illumina MiSeq.
• Bioinformatic analysis for whole genome assembly and strain characterization.
• Comparison of antigenic epitopes between breakthrough strains and vaccine strains.

Main Results:

• Four out of 76 (5.2%) specimens were positive for rotavirus.
• Identified reassortant strains (RVA/Human-wt/ZMB/CIDRZ-RV2088/2020/G1P[4] and RVA/Human-wt/ZMB/CIDRZ-RV2106/2020/G12P[4]) and a typical Wa-like strain (RVA/Human-wt/ZMB/CIDRZ-RV2150/2020/G12P[8]).
• Observed amino acid differences in VP7 and VP4 antigenic epitopes between breakthrough and Rotarix vaccine strains, suggesting a role in immune evasion.

Conclusions:

• The identified reassortant rotavirus strains possess genetic variations potentially contributing to immune evasion.
• These findings underscore the importance of ongoing surveillance and genetic characterization of rotavirus strains.
• The study provides crucial data to inform national rotavirus vaccination strategies and the development of next-generation universal rotavirus vaccines.