A woman takes a test for the coronavirus disease (COVID-19) at a testing centre in Sydney, Australia, January 5, 2022.
A woman takes a test for the coronavirus disease (COVID-19) at a testing centre in Sydney, Australia, January 5, 2022. Reuters / JAIMI JOY

Australia said on Thursday it would expand the rollout of the fourth dose of COVID-19 vaccines from next week as it battles a steady rise in hospital admissions fuelled by the highly transmissible new Omicron subvariants, BA.4 and BA.5.

The new subvariants have now become the dominant coronavirus strains in several countries, with pandemic experts warning they could lead to more hospitalisations and deaths because they spread more quickly than other coronavirus variants.

New South Wales, Australia's most populous state, warned it was experiencing a fresh wave of infections driven by the BA.4 and BA.5 variants. Meanwhile, Victoria said these have become the dominant strains in the state.

"The pandemic is not over, we are entering a third wave that is placing enormous pressure on our health and hospital system," Health Minister Mark Butler said during a media briefing.

About 4,000 people are currently in hospitals in Australia suffering from COVID, the biggest count since early February, authorities said, when Australia endured its previous significant Omicron outbreak.

From Monday, people aged above 30 will be eligible for the fourth dose, Butler said, after Australia's immunisation advisory group updated its recommendations.

The changes will make more than 7 million people eligible for their second booster shot. The vaccination has been restricted up to now to people above 65 or with serious illness.

After largely containing the virus through tough border restrictions and snap lockdowns earlier in the pandemic, Australia began living with the virus late last year through a staggered easing of curbs after higher vaccinations.

An Australian National University survey released on Thursday showed young Australians have suffered the greatest drop in life satisfaction among all citizens during the first two years of the COVID-19 pandemic.

Australia on Wednesday scrapped a rule that required international travellers to declare their COVID vaccination status, marking the end of another major restriction.

Australia, among the most heavily vaccinated countries against COVID, has so far administered two doses to 95% of people above 16. More than 70% have been given a third shot, official data showed.

This has helped Australia to restrict its COVID numbers. The total death toll rose above 10,000 on Sunday, but the rise has been far slower than in many other countries.