New subvariants loom as winter wave nears end

Michael Ramsey
Aug 15, 2022, updated Aug 15, 2022

Australia’s latest wave of COVID infections may be nearing its end but new subvariants could soon bring a further spike in cases, an epidemiologist warns.

NSW and Victoria combined reported fewer than 10,000 new infections on Monday, while about 35,000 cases were announced nationwide at the weekend.

The seven-day average for case numbers in Australia has dropped to the lowest level since mid-February, according to Johns Hopkins data.

University of South Australia epidemiologist Adrian Esterman said while the wave linked to the highly infectious BA.4 and BA.5 Omicron subvariants appeared to have troughed, subvariants continued to emerge.

“We’re seeing a wave [of infections] due to new subvariants every three to four months and we have done for the last eight months,” he said.

“If the same pattern continues, we might expect a new wave from a new subvariant around November. And there’s already a couple on the horizon.”

Professor Esterman said the BA.2.75 variant was taking over as the dominant strain in India, while BA.4.6 had begun to take hold in parts of the US.

Those strains were almost certainly already in Australia but it was too soon to know whether they would become dominant or if a subvariant that caused more severe infections would assume their place, he said.

“There’s absolutely no guarantee the next wave that comes along isn’t going to be incredibly severe. We simply don’t know,” he said.

States and territories have largely rolled back protections, including mask mandates.

But Professor Esterman said the persistence of the virus meant there was a need for more public health measures, including greater education around mask-wearing and the importance of booster shots

“More important than the peaks of the waves is the height of the trough in between them,” he said.

“That’s staying relatively high and that means there’s constant pressure on our hospital systems and there’s constant pressure of people getting long COVID.”