As more people became eligible this week to receive a fourth vaccine dose, as well as antiviral treatments, Associate Professor Paul Griffin from the University of Queensland said people should not become complacent surrounding the virus.

He warned those who have recently come down with Covid-19 could become reinfected in a matter of weeks.

“We are seeing reinfections being more common and in short intervals, and that is why we recommend the reinfection period be reduced to four weeks,” he told the Seven network on Tuesday.

“If you get symptoms again, you need to assume it could be a new infection.”

He was speaking before it was revealed nearly 900 Queenslanders were in hospital with Covid-19, with cases surging and the peak of the current wave still weeks away.

Another 12 people died with the virus and 6768 new cases were recorded in Queensland on Tuesday, bringing the state’s active cases to 43,047.

Chief Health Officer John Gerrard said 860 patients were being treated in hospital, almost the same amount as there was during the first Omicron wave earlier this year.

He said with the peak still three weeks away, many more people could end up in hospital.

“It’s not hard to imagine that it’s going to exceed that 1000 number given that we still predict the peak won’t be until the first week of August at the earliest, it may be later,” Gerrard told reporters on Tuesday.

The Australian Health Protection Principal Committee recommended the reinfection period be reduced from its current 12 weeks to 28 days, following the rise of cases of the BA.4 and BA.5 Omicron variant.

Australia’s chief medical officer Professor Paul Kelly said hospital systems had come under more pressure due to the rise in cases.

He said the emergence of influenza for the first time in three years in Australia had also made the issue worse.

“All of that together has caused issues in our hospitals, and so (postponing elective surgeries) is a pretty standard thing to be done at this time of year during the winter season,” he told ABC TV on Tuesday.

“With this increase now in the new variant of Covid, that has exacerbated that problem.”

Health Minister Mark Butler said a rise in infections still had a long way to go.

Butler indicated Covid-19 cases are not likely to peak nationally for at least four weeks during this third wave of infections.

“All of the modelling indicates that case numbers and hospitalisations have further to go over probably the next four to six weeks,” he told Melbourne radio 3AW on Tuesday.

“We’ve seen some data out this morning that suggests that Covid is the largest killer of Australians this year, taking over from coronary disease.”

Prof Kelly said the rising number of reinfections had thrown a new curveball for handling the virus.

“The new BA.4 and BA.5 (Omicron variants) are more infectious and there is strong evidence that you can get reinfected earlier than what was previously the case,” he said.

Griffin said the rise in new Covid-19 infections alongside an increase in influenza cases was also concerning.

“This is translating into significant numbers in hospitals, with predictions … we may exceed the hospitalisations we saw in the first big wave in January,” he said.

“We cannot assume people are protected just because they’ve had Covid, you need to be up to date with your vaccines and linking with therapies if you are eligible.”

However, doctors have said antiviral treatments, which have become more readily available, are not a substitute for being vaccinated.

Royal Australian College of GPs vice-president Bruce Willett said the two measures were important but should be seen as having separate functions.

“One of the concerns with these antiviral agents is people may see them as a substitute for getting vaccinated – they definitely are not,” he told Sky News.

“Vaccination is still our first and foremost protection against severe Covid.”

He said vaccination could reduce a person’s chances of hospital admission or getting severe disease by a factor of five.

Dr Willett noted there was a problem in some rural and regional areas in getting access to the antiviral drugs, but it was likely to improve.

“We have all been caught a little bit on the hop with the expansion of the availability,” he said.

Australians over 70 who test positive for the virus were from Monday offered access to antivirals on the Pharmaceutical Benefits Scheme.

Access was also expanded to people over 50 with two or more risk factors for severe disease, and Aboriginal or Torres Strait Islander people over 30 with two or more risk factors.

Anyone 18 or over and immunocompromised may also be eligible.

Normally costing more than $1000, the two antiviral treatments are now available for $6.80 for concession card holders and about $40 for everyone else.