An infectious diseases physician has urged caution over a Queensland Health study comparing the impacts of COVID-19 and influenza, saying it is "very limited" and there is a danger of "downplaying the ongoing significance of COVID".
Results from the observational study appear in a one-page research poster being presented at an infectious diseases conference in Copenhagen.
The study concludes that in Queensland's highly vaccinated population infected with Omicron "long COVID may manifest as a post-viral syndrome of no greater incidence or severity than seasonal influenza after 12 weeks".
It found that out of 2,195 adults diagnosed with COVID-19, 21.4 per cent self-reported ongoing symptoms at 12 weeks and 4.1 per cent were classified as having "moderate to severe functional limitations".
The numbers were similar for influenza, with 23 per cent of the 951 adults diagnosed with the virus experiencing ongoing symptoms and 4.4 per cent having more serious limitations.
Infectious diseases physician and clinical microbiologist Paul Griffin said while the study is "perhaps a good preliminary report" it used a "very small sample size" and was not peer reviewed.
"We have a very limited snapshot of what the study actually included and when we look at peer-reviewed research there are other relevant experts who have thoroughly reviewed the methodology and the findings and the conclusions … so we can be assured a reasonable level of quality and scrutiny," he said.
"Those same things are not applied necessarily to a poster at a conference, so we just need to be a little bit cautious in terms of how much significance we pay to this type of research."
Queensland Chief Health Officer John Gerrard disagreed the sample size of 3,000 respondents was small.
He said the study has been submitted for peer review.
"A full peer-review process takes months.
"This has been an issue throughout the COVID pandemic where we're getting new data on a regular basis and we need to get it out to the public to inform them.
"I know people who are terrified of COVID, they're terrified of COVID because they think they're going to get long COVID and this sort of information is vital," Dr Gerrard said.
COVID's contribution to excess mortality
Dr Griffin said there is other data suggesting the impacts of COVID are far greater than from other similar respiratory viral infections.
"I think we do need to be really cautious in just now making conclusions that COVID and the flu are the same because I think a lot of other data would suggest otherwise."
"COVID has contributed to very significant excess mortality compared to what we would see in an ordinary year, not just those where it's been directly attributable but secondary complications that can be very significant," he said.
In a press release Premier Annastacia Palaszczuk said the state's "high vaccination rates protected Queenslanders from the worst of COVID-19".
"It is why I am proud to lead a government that did all it could to protect the community against COVID-19 when the pandemic was at its peak, including vaccinating 80 per cent of the population before reopening our borders," Ms Palaszczuk said.
But Dr Griffin raised concerns about Queensland's low COVID vaccine booster rates compared with other states.
"We're actually doing the worst at three doses and second worst at four doses, so our work with vaccination is not over," he said.
"If we are excessively reassuring people it can downplay the significance of COVID and trying to motivate people to get vaccinated and do those simple measures becomes even more challenging," he said.
Queensland Health senior epidemiologist, Ross Andrews, said the data was gathered through a text message questionnaire sent to Queenslanders 12 weeks after they had tested positive for COVID-19 or influenza in June 2022.
"The bottom line is that one in five people who had COVID still had ongoing symptoms 12 weeks later and similarly one in five people who had influenza still had ongoing symptoms 12 weeks later.
"When we asked about their functional impairment, or what you might call long COVID, one in 25 people who had COVID met the criteria that the WHO was outlining at that point for long COVID, but so did one in 25 people who had influenza," Professor Andrews said.
He said that while the study found similar rates of ongoing symptoms in the two groups, there was about 38 times the number of COVID-19 cases as there were influenza cases.
Dr Gerrard said he wanted to emphasise that "we believe long COVID is very real".
"But in a highly vaccinated population like we have in Queensland, it's very difficult to distinguish that in our study from a post-viral effect," Dr Gerrard said.
He said that while the findings are "heartening" there will still be a "significant number of people out there with long COVID" because the virus is so infectious.
"There has never been an infectious disease that has infected an entire state, 80 per cent of an entire state in 12 months," he said.
More than 400 COVID-19 deaths have been reported in Queensland so far this year.
There were eight influenza-associated deaths from January 1 to April 9.
