NSW Health authorities reported that the case of XE was detected in a recently returned overseas traveller last week.
It was confirmed in the weekly COVID-19 surveillance report NSW Health releases.
“This is the first XE sequence to be identified in NSW and was identified in a recently returned traveller,” NSW Health said in the report.
“Another recombinant BA.1/BA.2 sequence has previously been identified but it was not of the XE lineage.”
There is little data yet on the transmissibility or severity of the new sub-variant.
Victorian health authorities have also confirmed the detection of a new Omicron sub-variant in wastewater.
The sub-variant, which is believed to be either BA.4 or BA.5, has been confirmed from samples taken from the Tullamarine catchment.
“The sub-variant has been recently detected in a small number of cases in South Africa, Botswana, Belgium, Denmark, the United Kingdom and Germany,” Victoria Health said.
“There are currently no known significant epidemiological differences observed between the new strain and the BA.2 strain.”
The World Health Organisation did note last month that XE may be 10 per cent more transmissible than the currently dominant BA.2 Omicron sub-variant.
The Omicron BA.2 sub-variant has been the dominant infection in NSW for several weeks.
NSW Health prioritises the genomic sequencing of people hospitalised and admitted to ICU with COVID-19.
“Therefore the proportion of VOCs (variants of concern) is not necessarily reflective of their distribution in the community,” NSW Health said in the report.