New evidence about the virulence of the Delta strain of COVID-19 may mean unvaccinated people will be hospitalised at twice the rate previously predicted, says a trusted public health expert.
Modelling by the Doherty Institute used when setting targets of 70 and 80 per cent vaccination coverage for reopening did not reflect the true virulence of the Delta strain, the institute's Director of Epidemiology, Jodie McVernon, told a NSW parliamentary hearing on Thursday.
New international research shows severity of health outcomes from the Delta strain is worse than the original Alpha strain, and future Doherty modelling will now reflect this, she said.
If the severity from Delta is about twice what was originally assumed, the numbers of hospitalisations of unvaccinated people will probably be double what has been predicted, Professor McVernon agreed.
But the impacts on vaccinated people are difficult to predict.
The Doherty Institute modelling presented to national cabinet in July would not be significantly affected by the international research because the overall strategy was about minimising case numbers.
But there could be implications for the NSW government's modelling predicting the stress on the health system as hospitalisations peak next month.
The institute is currently examining whether there should be higher vaccine targets for certain vulnerable groups to ensure equitable health outcomes, she said.
They are also examining the roles of public health measures like exposure venue notifications, now that vaccination numbers and cases are higher than they once were.
"At low case numbers and with a zero COVID strategy, those kinds of things were really important because you couldn't afford to miss one (case)," said Professor McVernon.
But transmission in shops and supermarkets is "vanishingly rare".
Contact tracing and quarantine measures may need to be focused on areas with lower immunisation or higher risk in the future, she said.
Earlier on Thursday, NSW Health Minister Brad Hazzard said the state was just weeks away from "effectively cutting loose" after almost three months in lockdown.
But he urged everyone to remain disciplined until 70 per cent double-dose vaccination coverage is reached.
NSW reported 1063 new locally acquired cases of COVID-19 and six deaths in the 24 hours to 8pm on Wednesday.
Health Minister Brad Hazzard on Thursday acknowledged the pandemic had been "gruelling" for everyone.
But as vaccination coverage among those 16 and over continues to rise, the end of lockdown is drawing near.
Once 70 per cent double-dose coverage is reached, fully vaccinated NSW residents can again visit the homes of others and attend hospitality venues, retail outlets, gyms and sports matches.
These freedoms may be restored as soon as October 11, the Monday after the 70 per cent mark is likely to be reached.
Additional freedoms - including international travel - will be restored at 80 per cent double-dose coverage.
More than 83 per cent of NSW residents 16 and over have had at least one jab, and 55.46 per cent are fully vaccinated.
"We are getting there, it's a really positive time," Mr Hazzard said.
"We're moving towards Christmas and it looks like we'll all be able to effectively cut loose - there'll be some restrictions but we'll be able to have a much better life in the coming weeks."
Lismore and Albury were released from stay-at-home orders at midnight after no new cases were reported since they were locked down on September 16.
Several local council areas in the state's west were freed overnight too, with Gilgandra and Brewarrina now at least 14 days virus-free.
Restrictions will also ease in Narromine from Saturday provided the town has no cases or sewage detections before then.
The Glen Innes and Orange local government areas will also exit lockdown from Friday, but the one in Hilltops will remain.
Australian Associated Press
Sign up for our newsletter to stay up to date.