Too early to tell whether Omicron sub-variant causes more severe disease: experts

An Australian senior health official has said that a new COVID-19 sub-variant circulating in Australia is not yet causing concern among health experts.

Michael Kidd, deputy chief medical officer of Australia, on Monday said the Omicron BA.2 sub-variant, which was detected in Australia in December, may become the dominant sub-variant of Omicron based on some reports.

He said they were not seeing more severe disease associated with this sub-variant, and "it's also too early to tell" if there is any significant different impact on the effectiveness of the vaccines against this sub-variant.

"If this BA.2 sub-variant is shown to have more distinct clinical characteristics then the World Health Organization may determine, that it becomes a variant of its own, but it is too early to speculate on that, and we're not seeing indications of that at the moment," Kidd told reporters in Canberra.

Australia on Monday reported more than 30,000 locally-acquired coronavirus infections and 44 deaths – 27 in New South Wales, eight in Victoria, six in South Australia and three in Queensland, according to health department figures from states and territories.

More than four million additional Australians became eligible for booster vaccines on Monday, with the recommended interval between second and third doses being cut from four to three months.

Health Minister Greg Hunt confirmed that the government is preparing for the possibility of fourth vaccine doses for elderly and vulnerable Australians if needed.

"Most likely advice at this stage is that if there were to be a fourth dose it's more generally going to be focused on older Australians and immuno-compromised Australians, and perhaps those working in- with vulnerable patients," he said in the press conference with Kidd.

"So that's still under active medical consideration, but the supplies and logistics are in place to deliver that if it's required."