A range of Omicron subvariants were circulating in early to mid-2023, with XBB 1.16 – colloquially known as “Arcturus” – designated as a variant of interest by the World Health Organisation (WHO).
Originally detected in NSW in January, on April 17 the WHO said XBB 1.16’s increasing prevalence, as well as its increasing growth advantage, made it a variant of interest.
The WHO said the subvariant reached 32 nations beyond Australia, and that the vast majority of cases have been recorded in India.
While Arcturus was reported as being able to evade immune responses better than some other variants and subvariants, the WHO said it didn’t pose a significant additional health risk.
“While growth advantage and immune escape properties are observed in different countries and immune backgrounds, including in countries where XBB.1.5 has become the dominant variant recently, no changes in severity have been reported in countries where XBB.1.16 are reported to be circulating,” the WHO said in its initial risk assessment.
“In India and Indonesia, there has been a slight increase in bed occupancy numbers. However, the levels are much lower than seen in previous variant waves.”
XBB 1.16 is closely related to another Omicron subvariant, XBB 1.5.