Molecular epidemiology and evolution of norovirus in Australia and New Zealand, 2018 to 2020

Abstract

Background: Norovirus causes an estimated 699 million cases of gastroenteritis and 219,000 deaths each year. Historically, novel strains with a genogroup II genotype 4 (GII.4) capsid have emerged every 3–5 years to cause gastroenteritis pandemics. Contrary to historical trends, viruses with aGII.4 Sydney 2012 capsid have extended the timeframe of capsid circulation, well beyond the usual 3–5 years, through genetic recombination to obtain new non-structural regions, for example, a GII.P16 ORF1. Objectives and methods: The molecular evolution in the GII.4 capsid of strains in New South Wales (NSW), Australia and New Zealand (NZ) before and into the COVID-19 pandemic (2018–20) was investigated ..