Just as Covid-19 restrictions have been stripped away across most of Australia, a highly infectious sub-variant of Omicron has emerged and is posing a new threat.
In NSW this week, Health Minister Brad Hazzard revealed cases could “xjmtzywmore than double” in six weeks as a result of BA.2.
On Sunday, NSW recorded 13,093 infections, close to the state’s daily average this week.
The sub-variant is also sweeping across the rest of the country, including Western Australia, which is still yet to reach its peak of Omicron.
That is not expected to happen until next week, but Health Minister Amber-Jade Sanderson said the BA. 2 sub-variant had already been factored into the state’s modelling.
Across the world, many countries have experienced a surge in cases due to BA. 2, with the Statens Serum Institut issuing a warning about two weeks ago.
“BA. 2 is gaining ground in many places worldwide,” the Danish research institute said.
Here’s everything you need to know about the sub-variant.
What is BA. 2 and is it more transmissible than the original Omicron?
According to the World Health Organisation, BA. 2 differs from BA. 1 in its genetic sequence, including some amino acid differences in the spike protein and other proteins.
It has a growth advantage over BA. 1 but studies are ongoing to understand the reasons.
“Initial data suggest that BA. 2 appears inherently more transmissible than BA. 1, which currently remains the most common Omicron sub-lineage reported,” WHO said.
“This difference in transmissibility appears to be much smaller than, for example, the difference between BA. 1 and Delta.
“Although BA. 2 sequences are increasing in proportion relative to other Omicron sub-lineages … there is still a reported decline in overall cases globally.”
Australian Medical Association WA president Mark Duncan-Smith told reporters on Friday that the sub-variant was up to 40 per cent more transmissible.
“A virus just wants to replicate … but that typically occurs over years, if not decades,” he said.
Gaetan Burgio, from the Australian National University, told NCA NewsWire the BA. 2 variant was as virulent as the Omicron.
“Importantly, if someone has been infected with Omicron virus, the risk of reinfection with BA. 2 would be very low,” he said.
What impact will BA. 2 have in Australia?
Dr Burgio said in most states the BA. 2 variant had taken over Omicron and Delta.
“This is for example the case in ACT, Victoria, NSW and Queensland,” he said.
“The number of Covid-19 cases in Australia will steadily increase in the next three months, approximately.
“While more transmissible, the booster vaccination protects us relatively well against severe complications of the viruses.”
Professor Bruce Thompson, from the University of Melbourne, told NCA NewsWire it was still too early to tell the full extent of the impact that the sub-variant would have on the community.
“There’s different variants … you have things like Alpha, Delta and Omicron, which are sort of overall umbrellas, but then you can get changes with that as well,” he said.
“What would seem to be with this particular variant is that it’s more infectious, it’s more transmissible, but what is kind of interesting is the nature of the disease that you contract from the actual virus itself doesn’t seem to be a lot more different.
“If you look at Sydney in September last year, we didn’t have very high levels of vaccination and 10 per cent of the people that contracted Covid were landing themselves in hospital.
“Now vaccinations have increased so much so it’s less than one per cent — it’s fundamentally changed the nature of the condition.”
Professor Thompson said looking at the impact overseas, the sub-variant did not seem to change the nature of the disease.
Should we be worried about the sub-variant?
Dr Burgio said given more than 60 per cent of the Australian population had received their booster vaccination, we should not be too concerned — for now.
“However, as winter is approaching, co-infection with other respiratory viruses might change the level the level of concerns regarding the transmission and severity of this variant,” he said.
Dr Duncan-Smith agreed that now the borders were open the flu season would be significant this year.
Professor Thompson said the issue would really come down to the number of hospitalisations from Covid-19.
“That’s where the killer is for us all,” he said.
“If, ultimately, we have increasing cases because it’s more transmissible, but the actual nature of the disease is still overall manageable and the number of hospitalisations is still very low — and we’re such a highly vaccinated population anyway — then we’re probably going to be in a reasonably good place.”
What will happen next?
Professor Thompson said the most important things people could do was “be a little bit more sensible”.
He urged everyone to get vaccinated, use hand sanitiser, wear a mask and socially distance.
Dr Burgio warned it was possible that restrictions could return.
“However, it is always difficult to bring back restrictions once these have been relaxed or simply removed,” he said.
“The risk is the compliance would be quite low due to a fatigue effect from previous restrictions.”
Dr Duncan-Smith said it was possible the flu shot would eventually be combined with a Covid vaccine.
