Omicron variant expected to become dominant strain in Australia as NSW records 1,360 new Covid cases

A third booster Covid-19 vaccine dose will be essential to get high protection against symptoms from the Omicron variant and it appears likely the variant will become the dominant strain in Australia, virologists from the Kirby Institute say.

The new data from the Kirby Institute comes as Covid-19 case numbers in New South Wales jumped again on Wednesday to 1,360, 25 of them are the Omicron variant. There are now 89 Omicron cases in NSW.

The researchers also said Covid boosters may be required every six months to protect against the variant.

Virologists from the Kirby Institute presented new data on Wednesday after growing the Omicron variant in a laboratory and testing how it responded to various samples, including from the fully vaccinated, from those who had recovered from the virus but were unvaccinated, and those who had recovered from the virus and also received two vaccine doses.

The data has now been sent to all chief health officers across Australia.

Despite their vaccination status, they were as infectious as unvaccinated people, Turville said.

However, he said it was likely those two travellers had a poor vaccine response and this did not mean two doses of the vaccines offered zero protection against any infection from Omicron. Data from South Africa released overnight suggested protection from infection was 33% for those who are double-dosed, similar to the Kirby data which predicts 37%.