Queensland health authorities say they are "cautiously optimistic" about the status of the COVID-19 pandemic now hospitalisations are in decline and a "wall of immunity" has been built among the population.
With the state's mask-wearing mandate set to be reviewed at the end of the month and many freedoms reinstalled for Queenslanders, it might be easy to think the worst of the COVID-19 pandemic is behind us.
But with the flu season ahead and the possibility of new COVID-19 variants arriving, a Brisbane virologist has warned Queenslanders of the many uncertainties still at play.
University of Queensland virologist Kirsty Short said cases would never get down to zero.
"It's just not going to be like that," Dr Short said.
"We're probably going to get another little peak from schools reopening … that's going to take at least a week or so to come through in the case numbers.
"I think people should be reassured the cases haven't peaked at a higher number, but be aware it's not going to go back down to what we had before the borders reopened.
"What's going to happen with the flu season and what's it going to look like when influenza is circulating in the community?
"What effect will that have on our healthcare burden and respiratory disease?
"I think we just have to be cautious — I am not scared, I'm just not planning too far ahead.
"So I'm not assuming that as of this date, everything would go back to normal … we've just got to accept a level of uncertainty because we haven't been in this situation before."
Driving up infection-induced immunity
The warning comes as large parts of Queensland have either passed the peak of the Omicron wave or are approaching a peak.
Authorities said Gold Coast, Metro North, Metro South, Cairns, Sunshine Coast, West Moreton and Mackay health regions have passed the peak of the Omicron outbreak.
Townsville, Wide Bay, the North West and Torres Strait-Cape are approaching their peak, while the Darling Downs and Central Queensland are yet to reach a peak in infections.
Queensland Premier Annastacia Palaszczuk said while much of the state was still coming down off the peak of infections, we could expect to see a "tail end" in March ahead of the flu season.
In the daily COVID briefing yesterday, Chief Health Officer John Gerrard said initial modelling suggested it was still "credible" to assume half of the state's population would be infected by the end of the month.
Dr Gerrard said vaccinated Queenslanders had a "wall of immunity" but the effectiveness of vaccines during future COVID waves remained unclear.
"We'll be the first in the southern hemisphere to go into the winter following this international Omicron wave," Dr Gerrard said.
Dr Short said infectious diseases did not keep growing exponentially and the population would have immunity at some point from infections.
"We don't just have vaccine-induced immunity, we also have infection-induced immunity and together that's giving more people a level of protection,'' she said.
Dr Short said vaccine-driven immunity was much more consistent and generally better than infection-driven immunity.
Hospitalisation rate still falling
Ms Palaszczuk said yesterday the hospitalisation rate for COVID-19 cases had fallen well below the government's worst-case scenario, in which as many as 5,000 beds were forecast to be needed for patients.
"Our initial modelling, we looked at anywhere between 3,000 to 5,000 people we were expecting going into hospital and around 300 to 500 people going into ICU," Ms Palaszczuk said.
With 579 people hospitalised with the virus in the latest reporting period, Ms Palaszczuk said the state had passed its peak of hospitalisations.
Dr Short said the "worst-case scenario" in government modelling was partly for contingency planning but were also not "predictive".
"These are basically different scenarios — the particular scenario that we ended up having was with a variant that we didn't really foresee.
"What we see with this variant is that vaccinated individuals will get infected.
"That means that probably there's going to be a lot more mild cases because people who are protected against severe diseases are still getting infections versus people who didn't have any protection against the disease."
Nearly 60 per cent of eligible Queenslanders aged 16 and over have received a booster shot, while more than 90 per cent have received two vaccine doses.
Late yesterday, the Australian Technical Advisory Group on Immunisation (ATAGI) recommended Australians over the age of 16 be required to have three doses of vaccine to be considered fully vaccinated.
