Chief health officers are warning a new wave of COVID-19 cases will hit within weeks, driven by new subvariants with a high level of immune evasion.

NSW was already seeing an uptick in cases amid the emergence of two subvariants called BQ.1 and XBB, its Chief Health Officer Dr Kerry Chant said on Thursday. 

Victoria Chief Health Officer Professor Brett Sutton said that these subvariants now comprised about 10% of some 8500 new cases in his state over the last week, a calculation based on wastewater testing.  

He added they were both “driving significant case and hospitalisation waves overseas due to their ability to escape immunity from past infection, including BA.5, and waning immunity from past vaccination”.