A second wave of Omicron is underway across the world driven by the BA.2 subvariant and now accounts for least 60% of new COVID-19 infections.¹

The proportion of cases due to BA.2 in Australia varies between states and territories – but is as high as 70% in SA according to the state’s Chief Public Health Officer Professor Nicola Spurrier earlier this month – with almost all of the remainder due to BA.1. 

Interestingly, both BA.1 and BA.2 emerged simultaneously from Gauteng Province, South Africa, in late 2021. 

But BA.2 contains 50 different amino acids to BA.1, twice that between previous variants of concern and the ancestral Wuhan strain.