There is growing evidence that about 10% of people with Covid-19 will go on to experience ‘long Covid’, where symptoms such as fatigue, shortness of breath, fevers, gastrointestinal issues, sleep disorders, ‘brain fog’, anxiety, post-traumatic stress disorder (PTSD) and depression persist for 12 weeks or longer. The proportion of people affected by long Covid indicates that there could be almost a million people affected in the UK.
Data from multiple sources report the persistence of symptoms of Covid-19. The UK’s Office for National Statistics (ONS) shows that around one in ten people who tested positive for Covid-19 and responded to the survey had symptoms that persisted for 12 weeks or longer. Another study from Wuhan, China, found that three-quarters of patients discharged from the hospital still had at least one symptom after six months, and a study from Italy found that 87% of patients reported at least one symptom, particularly fatigue and dyspnea, after two months. Similar long-lasting symptoms have been observed in survivors of other coronavirus diseases. Many severe acute respiratory syndrome (SARS) patients develop chronic fatigue, and some Middle East respiratory syndrome (MERS) patients exhibit similar persistent symptoms.
These long-lasting symptoms are supported by Perspectum’s COVERSCAN study, in which magnetic resonance imaging (MRI) scans of around 200 long Covid patients at around four months after infection showed multi-organ involvement in the heart and lungs. This damage could increase the risk of heart complications and heart failure for long Covid patients. The lungs of Covid-19 patients can develop scar tissue due to pneumonia, leading to long-term breathing problems, and the brains of Covid-19 patients can be affected by strokes or seizures and may have an increased risk of developing Parkinson’s disease or Alzheimer’s disease. These issues could be caused by inflammatory cytokine production or the pro-coagulation state induced by Covid-19, which can induce small clots in the capillaries and can also cause long-lasting problems with the liver and kidneys.
Studies on long Covid have reported associations between pre-existing respiratory disease, higher body mass index (BMI) and older age for dyspnea at four to eight weeks. There are also possible sex differences, with women being more likely to experience fatigue, anxiety and depression at six months after infection. A study of 4,182 confirmed Covid-19 patients out of 2.6 million users of the Covid Symptom Study mobile app in the US and UK with self-reported symptoms found that those who were older, female, had asthma or experienced five or more symptoms were more likely to go on to develop long Covid. The application algorithm is 70% accurate in predicting the likelihood of developing long Covid.
Given recent findings that nearly one-third of previously hospitalised Covid-19 patients in the UK are readmitted for further treatment within five months after infection, and one in eight readmitted Covid-19 patients died in that same timeframe, further follow-ups on the long-term effects of the disease needs to be conducted, along with treatments to prevent these outcomes. The National Institutes of Health (NIH) has recently announced a $1.5bn investment to address these issues for long Covid.