The head of the Australian Medical Association (AMA) in South Australia says the organisation is "already concerned" about the BA.2.75 subvariant of COVID-19 "on the horizon", but the federal health department says there has only been 150 recorded cases in the country so far.
The chief scientist with the World Health Organization (WHO) says the Omicron subvariant appeared to have mutated in a way that could indicate "major immune escape".
"We've had several cases of it here in South Australia," AMA SA president Michelle Atchison said.
"... It's got a potential, if it does take hold here in Australia, that it will become the dominant variant and then there will be a likelihood that you may get infected with that, even if you've had the recent BA.5 variant."
SA Health said 16 BA.2.75 cases had so far been identified in South Australia, with 90 per cent of them in returning overseas travellers.
None had been identified in the past week, a spokeswoman for the department said.
Recent genomic sampling found 98 per cent of cases in the state were from the BA.2, BA.4 or BA.5 subvariants.
The federal Department of Health said "fewer than 150 sequences" associated with BA.2.75 had been identified in Australia so far.
"At this point BA2.75 has not been designated a variant of concern by WHO, and there is no available evidence showing that it has a significant impact on transmissibility, severity and/or immunity compared with other variants," a spokesman said.
South Australian Health Minister Chris Picton said the state had not seen increasing numbers of BA.2.75, according to the latest update he had been given.
"What we are continuing to see is BA.5," he said.
"We are continuing to monitor other variants around the world.
"There's a number of sub strains of Omicron in the United States as well that we're monitoring however, we haven't seen any take-off of anything of concern at this stage in South Australia."
The most recent NSW data showed the new subvariant made up 1.5 per cent of samples there.
Doctors' union against reducing isolation period
National Cabinet is discussing COVID isolation periods today, with NSW Premier Dominic Perrottet leading the push to reduce it from seven to five days.
Dr Atchison said the body would have "considerable concerns" if the isolation period was reduced.
"We know that five days into a COVID infection many people will still be having symptoms, still be feeling unwell, and therefore are probably infectious," she told ABC Radio Adelaide.
Dr Atchison urged the government to listen to health advice rather than make decisions based on business and economic pressures.
"We've seen so many of these decisions made for other reasons, not for health reasons," she said.
Dr Atchison said businesses will "shoot themselves in the foot" if staff return while contagious and spread the virus.
While there has been a push towards personal responsibility over mandates, Dr Atchison said some workers may feel "coerced" to come back to work at the end of their isolation period even if they do not feel well — particularly casuals or people without enough sick leave.
"There's that pressure to go back to work even if you're not feeling 100 per cent," she said.
Dr Atchison said a five-day isolation period would not be appropriate in some sectors.
"I can just imagine it'd be a potential disaster if the aged care sector said, 'OK, bring everyone back to work as quickly as possible'," she said.
Dr Atchison said the state of the health system was an important consideration when deciding to cut the isolation period.
"Our health system is struggling, it's on its knees at the moment," she said.
"We just can't afford to have large numbers of cases."
