Nearly one in three people or about 30 per cent treated for SARS-CoV-2 are likely to develop post acute sequelae of Covid-19 (PASC), most commonly known as long Covid.
People with a history of hospitalisation, diabetes, and higher body mass index were most likely to develop the condition, while those who had undergone an organ transplant were less likely to develop it.
Surprisingly, ethnicity, older age, and socioeconomic status were not associated with the syndrome even though those characteristics have been linked with severe illness and greater risk of death from Covid-19.
Researchers from the University of California – Los Angeles analysed 309 people with long Covid. They found fatigue and shortness of breath (31 per cent and 15 per cent, respectively) to be the most persistent symptoms in hospitalised persons, and loss of sense of smell (16 per cent) in outpatients.
The incidence and risk factors of Long Covid, and even how to define the syndrome, have remained unclear throughout the pandemic.
“This study illustrates the need to follow diverse patient populations longitudinally to understand the long Covid disease trajectory and evaluate how individual factors such as pre-existing co-morbidities, sociodemographic factors, vaccination status and virus variant type affect type and persistence of long Covid symptoms,” said Dr Sun Yoo, health sciences assistant clinical professor at UCLA.
In March, University of Cambridge in the UK reported results of twin studies that showed seven in 10 long Covid patients experience concentration and memory problems several months after the initial onset of their disease, with many performing worse than their peers on cognitive tests.
The results revealed a consistent pattern of ongoing memory problems in those who had suffered Covid-19 infection. Problems were more pronounced in people whose overall ongoing symptoms were more severe.
“Studying outcomes in a single health system can minimise variation in quality of medical care. Because persistent symptoms can be subjective in nature, we need better tools to accurately diagnose long Covid and to differentiate it from exacerbations of other emerging or chronic conditions,” Yoo said.
Yoo also presses the need to ensure equitable access to outpatient long Covid care.