NSW residents are being warned about a new Omicron sub-variant that's taking hold across the state, as experts urge Aussies to remain vigilant amid changing Covid-19 behaviours.
Originating in South Africa, the new BA.5 sub-variant has tripled in cases in NSW since the start of June, overtaking BA.2 — which has halved — as the most dominant variant, the latest respiratory surveillance report showed.
Epidemiologist Margaret Hellard told Today on Friday booster jabs remain the best source of protection against Covid-19, and vaccination rates are waning.
Millions of people are reportedly overdue for coronavirus boosters and are being urged to act now.
NSW has a lower uptake of Covid-19 boosters than everywhere except Queensland and the Northern Territory, The Sydney Morning Herald reported.
"At present, it looks like this will drive a rise in infections similar to what we saw with the BA.2 wave,” Associate Professor James Wood told the newspaper.
Cases of the BA.2 sub-variant peaked around March in NSW, but new figures show it's slowing down.
"It is expected that BA.4 and BA.5 will become the dominant strain and will likely be associated with an increase in infections in the coming weeks," the respiratory surveillance report said.
The report also said that BA.4 and BA.5 sub-lineages "have a growth advantage" over the BA.2 sub-lineage, although there is "no evidence of a difference in disease severity."
This is because "BA.4 and BA.5 evade existing immune responses from both infection and vaccination better than previous Omicron sub-variants", Professor Wood explained.
If you are wondering why case numbers are starting to rise, Omicron BA.5 is now accounting for 35% of sequences genotyped in Australia.
— Professor Adrian Esterman (@profesterman) June 17, 2022
The prediction comes as mask mandates are beings scrapped at airports around the country.
Overall, Covid-19 transmission in the community remains high but continues to trend downwards, the latest report shows.
However, there's also been a decrease in PCR and RAT testing which could impact these numbers.
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