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A man receives a 4th Covid booster shot on July 11 in Melbourne . Photo : Asanka Ratnayake / Getty Images
We weren ’ t expecting them to get COVID again , but here we are .
Not over yet
Omicron sub-variants likely to push up COVID cases .
By Elise Hartevelt
Fully vaccinated Australians are becoming sick again as Omicron ’ s newest mutations cause a surge in COVID cases across all states .
Experts worry that sub-variants BA . 4 and BA . 5 , coupled with low influenza immunity in the community , will increase the strain on hospitals .
Research officer Ashleigh Porter from the University of Melbourne specialises in how viruses emerge and evolve in new hosts . She foreshadows the new variants ’ increased transmissibility will lead to many Australians being unable to fight off another COVID infection .
“ Just the reinfection – everyone out there who ’ s had a vaccine or was sick recently – we weren ’ t expecting them to get COVID again , but here we are ,” Ashleigh says .
The new strains are particularly growing in NSW and currently represent 35 per cent of specimens , prompting NSW ’ s weekly respiratory surveillance report to say BA . 4 and BA . 5 sub-variants will likely become the dominant strain .
Ashleigh says the new strains have the ability to reinfect individuals who have
been fully vaccinated and / or had a recent COVID-19 infection .
“ It ’ s definitely concerning ,” she says . “ It can spread in populations that have really high vaccination rates .
“ So with the little restrictions that we have at the moment on global movement , or even move between states , it means they will be able to spread quite rapidly .”
Alarming research proving BA . 4 and BA . 5 can evade immunity is quickly piling up , raising concerns among researchers and the community .
Another study found that these strains displayed the ability to bypass the human antibody response .
Not only can they reinfect the 95 per cent of fully-vaccinated Australians , but they may also overlap with other variants of COVID-19 , Ashleigh says .
“ The main concern is that they ’ re capable of reinfection .
“ And with the ability to evade vaccine immunity , or even if you ’ ve had a previous case and evade that immunity , it also means that it can co-infect with other lineages of SARS-CoV-2 .
“ We ’ re also seeing these recombinant lineages , which is when you get infected with two different types of SARS-CoV-2 at once , and they can swap DNA and form lineages , which is pretty concerning as well .”
Because of differences in spike glycoprotein , which influences how the virus engages with cells , the subvariants are ‘ tougher ’ than its previous strain , BA . 2 .
For example , research found that they bind to particular proteins in the lung ’ s linings more effectively than other sub-variants .
Yet Ashleigh says there ’ s no certainty that BA . 4 and BA . 5 are more harmful .
“ The mutations in the spike protein are concerning , which is how the virus attaches to human cells ,” she says .
“ So any mutations are usually ones that we would look at pretty closely .
“ But they ’ re so new it ’ s really hard to say whether or not they ’ re going to be more virulent or not .”
Ashleigh is particularly concerned about new mutations from animals bouncing back to humans . Yet , peak bodies have hardly been tracking the evolution of the virus in animals .
She says it ’ s unsettling , considering that the spread of early SARS-CoV-2 most likely originated from a mammal host .
Transmission across non-human species can present the virus with new possibilities to mutate into other lineages and take on selective adaptations .
“ We ’ ve already seen it before ,” Ashleigh said . “ I think there ’ s a lot of potential for the virus to keep evolving while we ’ re not keeping track of it .
“ Especially because there ’ s a proven risk of the virus spilling out of other animal populations to humans .”
To tackle this issue , she recommends that surveillance be set up for SARS-CoV-2 in animals that it can infect .
She also emphasises that the community has to continue to be vigilant and stay protected .
“ Stopping the transmission of COVID is the best way to prevent it from generating mutations .
“ I ’ m still a big believer in the nonpharmaceutical interventions as well , such as mask-wearing , social distancing – they worked well when we didn ’ t have a vaccine .
“ Even though we have the vaccine now , we should still keep them around .” ■
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