There's been a striking change in how the latest is impacting one particular age group and there could be a "perverse" reason for this.
Earlier this year, the summer Omicron wave was dubbed a "young epidemic" that saw hospitalisations skyrocket, especially in NSW and Victoria, with young Australians particularly affected.
But the current winter wave, driven by the more infectious subvariants BA.4 and BA.5 now appears to be having a larger impact on those older than 60.
A graph tracking hospitalisations shows a clear jump in the proportion of older patients towards mid-to-late April.
Source: SBS News
Just under half of those hospitalised in the week ending 26 February were aged over 60. But this had grown to around 66 per cent by the week ending 30 July.
'Perverse' reason COVID wave may be impacting older people
Infectious diseases expert Professor Peter Collignon of the Australian National University said there could be many complex factors contributing to older people making up a higher proportion of hospital admissions.
However, he noted the January outbreak impacted young people more because they were the ones most likely to be socialising after lockdowns.
It is definitely affecting older people more than previous waves.Professor Peter Collignon
"They just got out there and really, if you like, partied," Professor Collignon told SBS News. "So there was a lot more infection in that age group."
In contrast, many older Australians, who are at higher risk of severe disease and death from COVID-19, continued to limit their interactions and were more cautious, meaning they were less likely to get infected.
For the young people who did get COVID-19, this also gave them an immunity boost, which combined with a good uptake of vaccinations, may have provided them with "hybrid immunity" that is more protective than just being vaccinated.
"It perversely means that older people are a bit more vulnerable as a proportion of the population," Professor Collignon said.
The latest COVID-19 wave has been described as a and Professor Collignon says cases may partly be driven by the relaxation of mask use, social distancing and indoor socialising.
He said COVID-19 was now "going through to everyone", partly driven by the emergence of the more infectious BA.4 and BA.5 subvariants.
"I think a bigger proportion [of older people] are infected compared to particularly a year ago because there's so much circulation," Professor Collignon said.
"It is definitely affecting older people more than previous waves."
Once infected, older people are also more likely than younger Australians to be hospitalised due to serious illness.
Almost four-fold increase in cases
NSW Health Minister Brad Hazzard told SBS News people aged over 65 were making up a greater proportion of infections during the current winter wave, compared to the earlier summer wave driven by subvariants BA.1 and BA.2.
"It's almost a four-fold increase in the number of cases being older people," Mr Hazzard said.
NSW Health Minister Brad Hazzard says the latest COVID wave is having a greater impact on older people than previous waves. Source: AAP
Around 16,823 tested positive to COVID-19 in the week to 30 July, compared to 4,174 in March.
While some of the difference could be related to young people being less likely to report positive test results now, Mr Hazzard says more older people were getting infected.
"The clear message is that older people are still more vulnerable," he said.
"They should be doing everything possible to get the vaccine doses."
Vaccinations could also be playing a part
Burnet Institute epidemiologist Professor Michael Toole said the reluctance of Australians to get a third and fourth vaccine dose could also be playing a part.
He said in January more than 90 per cent of all age groups had received two vaccine doses in most jurisdictions.
"Just about everyone was equal in terms of two doses," Professor Toole told SBS News.
This meant the January wave was "overwhelmingly a young epidemic" because COVID-19 was spreading mainly among young people.
Young people may have better immunity to COVID after getting infected earlier this year. Source: Getty
Only 70 per cent of Australians had received at least three doses by 14 May, with many likely overdue for their jabs at this point.
While third dose figures have since improved, the Australian Technical Advisory Group on Immunisation (ATAGI) has since recommended a fourth dose for those aged over 50 years old.
Federal health department figures released this week show just 63 per cent of those aged over 65 have had the second booster.
COVID vaccination rates among people over 65 have dropped off. Source: SBS News
Australian Bureau of Statistics data released in February found COVID death rates were higher in older populations and among those with pre-existing conditions. It also showed death rates among .
NSW Health Department data suggests COVID-19 infections in NSW have peaked, and hospitalisations have plateaued, but Mr Hazzard said this doesn't mean people should stop being careful.
"One plateau coming to an end, based on past experience, doesn't guarantee there won't be another," he said.
"Just think back folks, we've all lived through it ... I don't think this virus is going to give up easily."
