The risks of developing Long Covid appear to have been exaggerated by flawed research, academics have suggested in a new paper published in the BMJ. The Telegraph has more.
Most people who contract coronavirus feel better within days or weeks, but for some people symptoms can last longer than 12 weeks.
Those who have Long Covid, also known as post-acute sequelae of COVID-19 (PASC), report fatigue, brain fog, chest pain and shortness of breath.
However, analysis from researchers in the U.K., Denmark and the U.S. suggests “major flaws” in the body of literature on the condition have probably exaggerated the true threat of developing it.
The analysis, published today, says “many scientific publications” overestimate the prevalence of long Covid due to “overly broad definitions, lack of control groups, inappropriate control groups, and other methodological flaws”.
Researchers said weaknesses in such studies may have fuelled public anxiety as well as causing misdiagnoses and diversion of funds from other long-term conditions.
The paper, published in BMJ Evidence-Based Medicine, looked at the definition of Long Covid by a number of global health organisations, including the National Institute for Health and Care Excellence (Nice) and the World Health Organisation (WHO).
Researchers said “none of them requires a causal link” with coronavirus infection meaning any new symptoms after a confirmed or suspected infection can end up being assumed to be Long Covid.
“In general, in the scientific literature, imprecise definitions have resulted in more than 200 symptoms being associated with the condition termed long Covid,” they said.
The team also points out that studies in the early stages of the pandemic are likely to have included fewer patients with mild or no symptoms.
They highlighted a recent review which found that 54% of studies of long Covid interventions included lab-confirmed infections.
This could lead to sampling bias, they said, which occurs when certain groups are more likely to be included in a study than others, limiting the findings.
Many symptoms assumed to be those of Long Covid are shared with other upper respiratory viruses.
They added: “Our analysis indicates that, in addition to including appropriately matched controls, there is a need for better case definitions and more stringent (Long Covid) criteria.”
It should include continuous symptoms after confirmed SARS-CoV-2 infection and take into consideration baseline characteristics, including “physical and mental health, which may contribute to an individual’s post Covid experience.”
Worth reading in full.
Stop Press: The Mail in its coverage highlights research from Harvard and Yale looking at ‘Long Vaccine‘ – the “debilitating suite of symptoms linked to Covid shot that last months and resemble Long Covid”.
Stop Press 2: Dr. Robert Dingwall writes in the Telegraph that “‘Long Covid’ is a failure of science” as it “offers opportunities to a medical-industrial complex to gain access to public funding for research, while the real victims get lost”.