Two notorious COVID-19 super spreader events that turbo charged the outbreak of Omicron in Newcastle have been analysed to better understand the highly infectious virus variant.
Health restrictions coupled with a booster shot are the best way to curb the Omicron wave, according to a National Centre for Immunisation Research and Surveillance study published on Thursday.
Two infected men who went to party at Newcastle's Argyle House nightclub in early December ended up passing the virus onto hundreds of revellers - most of whom where double vaccinated.
"At both of the Newcastle indoor entertainment venues, one a nightclub and the other a ball, at least 95 per cent of people had two doses of a COVID-19 vaccine but of those followed-up approximately 55 per cent tested positive," lead author Associate Professor Bette Liu said.
At least 664 people attended the nightclub, while 189 were at a University of Newcastle graduation ball two nights later.
The study looked at how the outbreaks in the venues occurred where "there was no mask wearing, nor strict control on density limits" with plenty of activities where virus transmission was rife.
These included "energetic dancing, drinking and close face-to-face contact in mostly small, crowded and poorly ventilated rooms with few external open windows".
Dr Liu said the findings suggest "recent vaccination with two doses was moderately effective in preventing infection with the Omicron variant" but it was not enough.
She recommended adhering to social restrictions and being vaccinated with "two doses and a booster, to reduce infection risk".
None of those infected in the outbreaks were admitted to hospital because of COVID-19, mostly due to their youth.
The report comes as NSW eases a swathe of restrictions at indoor venues and schools.
Masks will no longer need to be worn in shops from Friday, but will remain compulsory on public transport, at airports and on planes, as well as in hospitals, aged and disability care facilities.
They will also still be required to visit prisons and at indoor music festivals with more than 1000 people.
NSW Health reports 52.6 per cent of people 16 and older have now received a COVID-19 booster shot.
Professor David Durrheim, Health Protection Director at the Hunter New England Local Health District, says the study - along with data from the UK and South Africa - shows the importance of boosters complementing mask-wearing and social distancing.
"While we can see moderate protection against hospitalisation for the Omicron variant following two vaccine doses, protection wanes from two to three months after the second dose but is increased significantly following a booster," the study co-author said.
"Our study reinforces the need for the public health measures, including wearing masks indoors ... density limits, increased ventilation and restrictions on dancing and singing".
NSW on Thursday recorded 8271 new COVID-19 cases and 12 deaths.
