New York, Apr 3 (IANS): SARS-CoV-2 infection is not alone behind long Covid conditions, psychosocial factors such as low physical activity and loneliness may also contribute, according to a study led by an international team of researchers.

The World Health Organisation (WHO) defines post-Covid-19 condition (PCC) as the persistence of symptoms such as fatigue, dyspnoea, and what is commonly referred to as "brain fog" occurring three months or longer after infection with SARS-CoV-2.

The study, published in the JAMA Network Open, showed that the prevalence of long Covid conditions was equally high among people without a history of mild SARS-CoV-2 infection, suggesting contributions of other factors.

The prevalence of PCC six months after acute Covid was approximately 50 per cent, but was equally high in a control group of comparable SARS-CoV-2-negative individuals (47 per cent).

Acute Covid was not an independent risk factor for PCC, the researchers said, noting that low physical activity and loneliness were also associated with the outcome.

"These results suggest that factors often labelled as psychosocial should be considered risk factors for persistent symptoms," the researchers said.

However, "this does not imply that PCC is 'all in the mind', or that the condition has a homogeneous, psychological aetiology. Rather, there might be heterogeneous biological, psychological, and social factors engaged in triggering and maintaining the symptoms of the individual," they said.

For the study, researchers, including from Akershus University Hospital in Norway, University College London, UK; and University of Sydney in Australia, used a prospective cohort study involving 404 people who tested positive for SARS-CoV-2 and 105 who tested negative.

The team evaluated the participants during the early convalescent stage and at six-month follow-up.

Study subjects underwent clinical exams, including pulmonary, cardiac, and blood tests to examine immunological and organ injury biomarkers.

Researchers also conducted cognitive functional tests.

The team didn't find any biomarkers specific to viral infection at six-month follow-up. The main risk factor for PCC was symptom severity at baseline.