The coronavirus 'long-haulers' show how little we still know
To a physician scientist working on understanding the burden of respiratory infections, coronavirus is the ultimate professional challenge that might come by perhaps once in your career. However, I was not prepared for it becoming one of my biggest personal challenges too.
During the early stages of the outbreak, I came down with mild Covid-19like symptoms. Though I was slightly worried this would hinder my ability to contribute to the immediate professional battle against this virus, I also anticipated I would be back in business within a week or two. How wrong I was – I became what we now call a Covid-19 “long-hauler” – a patient with initially mild symptoms of likely Covid-19, who would go on to experience a range of sometimes severe symptoms for a prolonged period of time.
The Covid Symptom Study, undertaken by King’s College London, has revealed that 10% of all Covid-19 patients report symptoms for at least three weeks. Surprisingly, people in this socalled Covid tail are on average younger,. Most report having been previously healthy, and show relatively mild symptoms in the initial phase of illness. But they continue to experience symptoms such as fatigue, headache, cough, shortness of breath, chest pain, increased heart rates and gastrointestinal and neurological symptoms for weeks or even months following the initial symptoms; often these symptoms might come and go repeatedly.
Though physically I still struggle with lung problems, as a doctor and a scientist I struggle mostly with the lack of knowledge about this condition. We currently have no understanding at all of the biological mechanisms causing these prolonged symptoms. Theoretically, they may be the result of ongoing or resurgent viral replication – which would be important to know since this would imply prolonged infectiousness as well. Perhaps, however, as observed in more severe cases of coronavirus, the virus may trigger an aberrant immune response, resulting in ongoing inflammation throughout the body, which may last far beyond clearance of the virus. A third alternative, as observed commonly following bacterial pneumonia, is that the coronavirus causes more extensive damage of lungs, heart and other organ systems than suggested by the initial symptoms, which simply requires more time to recover.
Without this knowledge, we don’t know if long-haulers are infectious for prolonged periods, or whether they are at risk of experiencing severe complications, and certainly not whether treatment might reduce the duration of their problems. Left unattended, these patients may even develop irreversible damage leading to chronic illnesses.
Until we develop this medical and scientific knowledge, healthcare professionals won’t have the guidance needed to treat these long-haulers. Establishing specialty clinics to gather data from long-haulers in a systematic and concerted manner – comparable to what currently exists for severely ill adults following hospital discharge – would allow rapid development of guidelines for diagnostics, treatment and follow-up, with the focus on stimulating recovery and preventing development of chronic problems. However, this would be another big ask on already strained health services.
In dire need of recognition and support, a high number of long-haulers have organised themselves in online peer support groups. Depending on the country of origin, many report not having received any medical support during their illness, or being dismissed repeatedly. Others report being brushed off by healthcare professionals, misdiagnosed and in receipt of conflicting advice. They also experienced a wide range of stigma – friends keeping their distance for fear they might be infectious, sympathy draining because they “should” have recovered by now, and employers losing patience with the number of days taken off work. To support research and inform healthcare professionals, one Covid-19 support group in the US has already made a start in collecting and distributing health-related information from their members in a systematic way.
The emergence of this new group of long-haulers confirms once again the importance of testing all potential cases in the community, even mild ones, to confirm the presence of Covid-19. Given we do not know yet who will develop long-term complications, a confirmed diagnosis could help physicians to separate patients with likely Covid-19-induced long-term health problems from patients with other inflammation-driven illnesses, which, if misclassified, might lead to delays in treatment and long-term consequences.
In the last six months, Covid-19 has shown many faces, first caus
ing a high burden of acutely and severely ill patients requiring extensive and intensive care; second being linked with a rare but potentially severe syndrome in children resembling Kawasaki disease; and third a much more common protracted illness among initially mildly infected, and generally young and healthy, adults. This virus is not comparable to a simple flu. Therefore
we should focus on suppressing the virus as much as possible, even attempting to eliminate it, while we wait for the development of a vaccine.
• Debby Bogaert is a professor in paediatric infectious diseases at the University of Edinburgh