A new study questions whether Long COVID is any different to other long term virus effects.

Australian research to be presented at an upcoming infectious disease summit challenges the distinct classification of Long COVID, suggesting it may be indistinguishable from other post-viral syndromes a year after infection. 

The study, conducted by Queensland Health researchers, found no significant difference in moderate-to-severe functional limitations between individuals who tested positive for COVID-19 and those who had influenza.

The research, surveying over 5,000 symptomatic adults in Queensland during the Omicron variant wave, aims to reassess the perceived uniqueness of Long COVID symptoms.
The full study will be presented in April at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2024) in Barcelona, Spain.

Dr John Gerrard, Queensland's Chief Health Officer and the study's lead author, argues that the term ‘Long COVID’ might have contributed to a misconception of its uniqueness, proposing a reevaluation of such terminology to alleviate unwarranted fear and hypervigilance.

“In health systems with highly vaccinated populations, long COVID may have appeared to be a distinct and severe illness because of high volumes of COVID-19 cases during the pandemic. However, we found that the rates of ongoing symptoms and functional impairment are indistinguishable from other post-viral illnesses,” he said. 

The research team surveyed 5,112 individuals who showed symptoms of respiratory illness, including 2,399 with PCR-confirmed COVID-19 and 3,713 either negative for COVID-19 or positive for influenza. 

It found that 16 per cent of participants reported ongoing symptoms after a year, with 3.6 per cent experiencing moderate-to-severe functional impairment in daily activities.

However, no significant difference was found in the likelihood of experiencing moderate-to-severe functional limitations between those who had COVID-19 and those who did not or had influenza instead (3.0 per cent vs 4.1 per cent and 3.0 per cent vs 3.4 per cent, respectively).

The survey suggested a higher risk of moderate-to-severe functional impairment for individuals over 50 years of age and those presenting symptoms such as dizziness, muscle pain, shortness of breath, post-exertional malaise, and fatigue.

Expert opinions on the study are varied. 

Professor Philip Britton, a Paediatric Infectious Diseases physician from the University of Sydney, says he appreciates the study's insights but cautions against dismissing the term ‘Long COVID’ too hastily.

“There are likely reasons why persistent symptoms following COVID in this Queensland cohort may be no more frequent than following other viruses including the predominantly vaccinated cohort and the high frequency of Omicron variants,” he said. 

“These factors are acknowledged by the authors.

“It is because of these specific factors as well as inherent limitations of the study methodology itself, that their conclusion that it is ‘time to stop using terms like ‘long COVID’’ is overstated and potentially unhelpful. 

“Long COVID has been a global phenomenon, recognised by WHO.”

Professor Jeremy Nicholson from Murdoch University notes the complexity of COVID-19 and its long-term effects, stating that the study, while informative, does not conclusively prove that Long COVID is identical to flu-related post-viral syndromes. 

“As the authors of the new paper state, this is a post-viral syndrome of the sort that has long been recognised for other viral infections including influenza. The question is 'is long COVID unique, worthy of its own name, or is it just another post viral syndrome'?

“Unfortunately, this question 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.

“The absence of evidence is different from evidence of absence- so the authors' assertion that Long COVID is the same as flu-related post viral syndrome, is not proven, even if Long COVID is indeed a post-viral syndrome (which it is),” Professor Nicholson says.