Long Covid may be no different from other post-viral syndromes such as those experienced after flu, according to new research from Queensland Health.
The lead author of the study, the state’s chief health officer Dr John Gerrard, said it was “time to stop using terms like ‘long Covid’” because they imply there is something unique about the longer-term symptoms associated with the virus, and in some cases create hypervigilance.
There are different definitions of long Covid but the World Health Organization defines post-Covid or long Covid as occurring in people still experiencing symptoms three months after their initial Covid-19 infection, when those symptoms can’t be explained by an alternative diagnosis.
The study surveyed 5,112 adults who had symptoms of a respiratory illness and underwent PCR testing between May and June 2022. Of those, 2,399 were positive for Covid-19, 995 positive for influenza and 1,718 negative for both.
A year after their PCR test, participants were asked about ongoing symptoms and impairment using a questionnaire delivered by SMS link.
Overall, 16% reported ongoing symptoms a year later, and 3.6% reported moderate-to-severe impairment in their daily activities.
The results of the study, which Gerrard will present next month at the European Congress of Clinical Microbiology and Infectious Diseases in Barcelona, found no evidence that those who had Covid-19 were more likely to have functional limitations a year on compared with those who did not have Covid-19 (3.0% v 4.1%).
The 3% of the study participants who had ongoing impairments after Covid-19 infection was similar to the 3.4% with ongoing impairments after influenza.
The study also looked at specific symptoms in the patients who had moderate to severe impairment, and found in both patients who were Covid positive and negative, the same percentage (94%) reported one or more of the commonly reported symptoms of long Covid: fatigue, post exertional symptom exacerbation, brain fog and changes to taste and smell.
Gerrard said long Covid may have appeared to be a distinct and severe illness because of the high number of people infected with Covid-19 within a short period of time, rather than the severity of long Covid symptoms.
“We believe it is time to stop using terms like ‘long Covid’. They wrongly imply there is something unique and exceptional about longer-term symptoms associated with this virus. This terminology can cause unnecessary fear, and in some cases, hypervigilance to longer symptoms that can impede recovery.”
In a press conference on Friday, Gerrard said: “I want to make it clear that the symptoms that some patients described after having Covid-19 are real, and we believe they are real. What we are saying is that the incidence of these symptoms is no greater in Covid-19 than it is with other respiratory viruses, and that to use this term ‘long Covid’ is misleading and I believe harmful.”
The researchers acknowledged the findings are associations and do not represent prevalence, and acknowledged limitations in that participants who attended hospital or had pre-existing illness were not identifiable. They also said because 90% of people in Queensland were vaccinated when Omicron emerged, the lower severity of long Covid could be due to vaccination and the variant.
Prof Philip Britton, a paediatric infectious diseases physician from the University of Sydney and a member of the Long Covid Australia Collaboration, welcomed the study given the lack of published research from Australia in this area.
However, Britton said the conclusion that it was time to stop using terms such as long Covid was “overstated and potentially unhelpful. Long Covid has been a global phenomenon, recognised by WHO.”
Prof Jeremy Nicholson, the director of the Australian National Phenome Centre at Murdoch University, said the question of whether long Covid is unique “cannot be simply answered in this work”.
“The study is observational, based on reported symptoms with no physiological or detailed functional follow-up data. Without laboratory pathophysiological assessment of individual patients, it is impossible to say that this is indistinguishable from flu-related or any other post-viral syndrome,” Nicholson said.
• The headline of this article was amended on 16 March 2024 to clarify that it was the Queensland chief health officer’s conclusion that the use of the term ‘long Covid’ should stop, rather than it being a finding contained in the study.
