Australian Rotavirus Surveillance Program Annual Report, 2023

Area of Science:

• Virology and Epidemiology
• Public Health and Infectious Diseases
• Vaccinology

Background:

• Rotavirus is a leading cause of severe diarrheal disease in infants and young children globally.
• The Australian Rotavirus Surveillance Program monitors circulating rotavirus strains and their genotypes.
• Understanding rotavirus genotype distribution is essential for evaluating vaccine impact and guiding public health interventions.

Purpose of the Study:

• To report the circulating rotavirus G and P genotypes identified in Australia from January 1 to December 31, 2023.
• To analyze the proportion of wildtype and vaccine-like rotavirus strains.
• To assess the national and jurisdictional distribution of rotavirus genotypes.

Main Methods:

• Collection and analysis of 1,942 faecal samples referred for rotavirus G- and P- genotype analysis.
• Confirmation of rotavirus presence and subsequent G- and P- genotype determination.
• Categorization of strains into wildtype, vaccine-like (Rotarix), and unusual genotypes.

Main Results:

• A record 1,781 rotavirus-positive samples were confirmed, the highest in over 20 years.
• The dominant genotype was G3P[8] (71.9%), including human (42.6%) and equine-like (29.3%) variants.
• Other notable genotypes included G2P[4] (9.4%) and G12P[8] (6.4%). Vaccine-like strains accounted for 12.7% of positive samples.

Conclusions:

• The high number of positive samples reflects increased rotavirus disease notifications.
• Dominance of G3P[8] (human and equine-like) nationally, with regional variations, provides key data for vaccine program assessment.
• Ongoing surveillance is vital for tracking genotypic shifts, informing public health responses, and ensuring diagnostic quality assurance.