Patients with COVID-19 have greater odds of experiencing long-term effects than patients who recover from a bout with influenza, a new study has found.
The results suggest that these effects are linked directly to SARS-CoV-2 infection and are not just a general consequence of viral infection, say investigators from University of Oxford, in the United Kingdom.
Although long-term COVID-19 symptoms have garnered intense public interest, they have not yet been robustly examined, the researchers said. In a new study, they sought to estimate the incidence and co-occurrence of long-COVID symptoms, their relationship to age, sex, or severity of infection, and the extent to which they are specific to COVID-19.
To do so, they used electronic health records data of more than 273,000 patients diagnosed with COVID-19 and estimated the risk of having long-COVID effects within the six months following diagnosis. The incidence and co-occurrence were calculated for 9 “core features” of long-COVID. These included breathing difficulties/breathlessness, fatigue/malaise, chest/throat pain, headache, abdominal symptoms, myalgia, other pain, cognitive symptoms, and anxiety/depression.
The study compared the risk of developing these long-COVID symptoms between different groups in the COVID-19 patient population, and also to the risk of developing long-term effects after influenza illness.
Among the findings:
- More than 1 in 3 patients had one or more features of long-COVID recorded between 3 and 6 months after a diagnosis of COVID-19. This was significantly higher than after influenza.
- For 2 in 5 of the patients who had long-COVID features in the three- to six-month period, they had no record of any such feature in the previous 3 months.
- The risk of long-COVID features was linked to severe COVID-19 illness, and was slightly higher among females and young adults. White and non-white patients were equally affected.
Knowing the risk of long-term effects after COVID-19 may help clinicians and policy makers better plan healthcare services for these patients, said Maxime Taquet, Ph.D., of the university’s Department of Psychiatry.
In addition, the findings that patients who have long-term effects are more likely to show symptoms in the first 3 months may help in identifying those at greatest risk, he concluded.
Full findings were published in PLOS Global Public Health.
