As of March 2023, the Office for National Statistics estimated that 1.7 million people in the UK were living with self-reported long COVID. This refers to symptoms, including fatigue and brain fog among many others, that continue for more than 12 weeks after the initial COVID infection.
Long COVID is causing significant concern across the UK and around the world due to the large number of people affected. Research and anecdotal reports continue to show that the condition is causing severe symptoms. But we still need to learn more about how long COVID can affect a patient's ability to carry out normal, everyday activities.
In a new study, my colleagues and I found that long COVID can cause fatigue and affect a person's daily functioning more so than some cancers.
Fatigue appears to be the dominant symptom driving the effect on long COVID patients' capacity to function day-to-day, and is therefore an important focus for clinical care and the design of rehabilitation services.
Back in August 2020, we began a project to create a digital health intervention to help clinics remotely support long COVID patients. Our large, multidisciplinary team was created and led by the late Professor Elizabeth Murray. Over the two-year project, more than 8,000 patients from across 35 different NHS long COVID clinics in the UK used the Living With COVID Recovery mobile phone app.
The patients were encouraged to complete questionnaires on the app about how long COVID was affecting them, covering day-to-day activities, levels of fatigue, depression, anxiety, breathlessness and brain fog. This helped the patients track their symptoms over time and allowed clinicians to remotely monitor and support their patients.
The questionnaires also generated standardised scores for each symptom. This allowed the clinicians to compare the long COVID scores to those from patients suffering from a variety of other diseases gathered from previous research.
Analysing the data
William Henley and Sarah Walker at the University of Exeter analysed the data from the questionnaires completed by the first 3,754 patients to use the app, and the findings from these patients are reported in our study.
We found that many of the long COVID patients were seriously unwell, and often their symptoms were keeping them from doing day-to-day activities such as simple household chores or caring for other people. The extent to which long COVID patients were affected in this regard was comparable to patients who had had a stroke or were suffering from Parkinson's disease.
Of all the symptoms studied, fatigue was associated with the biggest effect on long COVID patients' daily lives, with average fatigue scores similar to or worse than people with cancer-related anaemia or severe kidney disease. The long COVID patients on average reported health-related quality of life scores which were lower than people with advanced metastatic cancers, such as stage 4 lung cancer.
The average long COVID patients we looked at were also suffering from anxiety, depression, breathlessness and brain fog, but these symptoms were not closely associated with an inability to carry out everyday activities in the same way as fatigue was.
Beyond the individual
It's likely that long COVID is also having a significant economic and social effect. Of the 3,754 long COVID patients in the study, 94% were of working age, and 51% said that they had missed at least one day of work in the previous month due to their symptoms. Further, 20% said they couldn't work at all during the previous month.
Notably, 71% of the patients reporting symptoms were women. Women tend to have more responsibilities at home and are more likely to work in caring professions, so long COVID will also have a large social impact.
Read more: Hair loss and lower libido among long COVID symptoms - new research
There were two main limitations in our study. First, our sample only comprises patients who were seen in a long COVID clinic, and this may not be representative of all patients with long COVID. Many long COVID sufferers may not have been referred to a clinic. The majority of patients in our study tended to be white, well-off and well-educated despite long COVID being more common in more deprived areas. People with the characteristics found in our study are more likely to seek out healthcare than their counterparts (namely those who are non-white, less well-off or less educated).
The second limitation is that the primary reason this data was collected was for clinicians to assess and treat patients, rather than for research. This led to substantial missing data as data was not collected in a systematic way. We didn't ask participants for data that wasn't deemed clinically essential, such as the severity of their initial COVID infection or COVID vaccination status as we didn't want to over-burden long COVID patients with too many questions.
Nonetheless, we hope that this work will inform clinicians and the general public about how unwell many patients with long COVID actually are. In particular, post-COVID assessment services should consider focusing on assessing and treating fatigue to maximise recovery and return to work for sufferers of long COVID.
Henry Goodfellow, NIHR Clinical Lecturer in eHealth, UCL