It's a tale of two outbreaks — and, as Charles Dickens wrote in the opening line of A Tale of Two Cities: "It was the best of times, it was the worst of times."
At least, that's the equation for NSW's hospitals when comparing COVID-19 data from last year's Delta surge with the current Omicron outbreak.
It's the best of times because the risk of getting severe disease right now, for most people, is lower.
But it's the worst of times because the number of people in NSW's hospitals with COVID-19 remains at its highest point ever, as a wave of infections washes over the state.
An ABC analysis of NSW Health data shows that while almost 2,200 patients are now hospitalised with COVID-19, only 7.8 per cent have been admitted to the ICU, and just 2.3 per cent need to be ventilated.
This compares with 18.4 per cent of patients who were in the ICU on September 14 last year, when case numbers peaked at 1,253 during the Delta outbreak.
Back then, 8.3 per cent needed ventilators.
Peter Collignon, an infectious diseases specialist from the Australian National University, said both vaccinations and the less severe Omicron variant were responsible for the fall.
"I think overall, this is good news, mostly because it means the vaccines are doing what they're designed to do, which is keep people out of hospital and stopping them from dying," he said.
Nhi Nguyen, an intensive care specialist at Sydney's Nepean Hospital, said in a press conference on Sunday that anecdotally, patients with the Delta strain tended to get severe pneumonia and have long stays in intensive care.
"Whereas those with Omicron, irrespective of needing to be in hospital, their hospital stays are much shorter," she said.
"What we're seeing is they're not needing to go on the ventilators."
Nhi Nguyen says the patients she has seen with the Omicron strain haven't needed long stays in hospital.(AAP: Joel Carrett)
A spokesperson for NSW Health said that since December 1 there had been a trend towards shorter hospital stays compared with earlier in the pandemic.
But Professor Collignon said the highly infectious nature of the Omicron variant was putting huge pressure on the community.
"While it's spreading a lot more than I would have expected, at least from an individual point of view, your risk is lower. But from a society point of view, it's 10 times lower risk but 10 times more spread."
Peter Collignon says the population is generally better off for two reasons — vaccination and the Omicron strain.(ABC News: Tamara Penniket)
Hospitalisations are rising by 100 or more a day in NSW.
Modelling released by NSW Health last week showed that 4,700 ward beds were predicted to be occupied by COVID-19 patients at the peak of the Omicron outbreak, which is expected to arrive in the next fortnight.
The total bed capacity in NSW is 9,500, with 12,500 beds available when private hospitals are added.
ICU admissions are predicted to peak at 273 patients in coming weeks.
Non-elective surgery in NSW was cancelled last week to cope with the flood of patients and Premier Dominic Perrottet said on Sunday that the state's health system was under pressure as high numbers of staff become infected.
A spokesperson for NSW Health said from December 16 to January 4, three quarters of the COVID-positive patients in the ICU had the Delta variant, and 62 per cent were not vaccinated.
NSW Health data showed that from June 16, 2021 up to Christmas Day, 2.1 per cent of unvaccinated people with COVID-19 ended up in the ICU or died, five times higher than vaccinated cases.
Up to June 2021, when very few people were vaccinated, 3.6 per cent of people with COVID-19 were admitted to the ICU or died, or both.
Professor Collignon said with unvaccinated people disproportionately affected, the way to stem hospitalisations was to get even more people jabbed.
"We were much better off last year than the year before," he said.
"There was many less deaths relatively speaking in September, October 2021, compared to what we saw in Melbourne the year before.
"And now we're better off again, and it's a combination of the two — vaccination and Omicron."
In NSW, 93.7 per cent of the adult population have been fully vaccinated and 95.1 per cent have had one dose.
On Monday, children aged between five and 11 became eligible to get the jab.