On the frequency and causes of prolonged covid symptoms.
Approximately 10% of people with symptomatic SARS-CoV-2 infection report persistent or recurring covid symptoms for several weeks or months. This notably includes younger and previously healthy individuals, as well as those whose original covid was mild or moderate (without hospitalization).
A small study by the US Center for Disease Control (CDC) found that up to 30% of non-hospitalized covid patients still experience typical symptoms after about one month. Among 18- to 35-year-olds without pre-existing conditions, the figure was still around 20%.
In the UK, a study found that by September 2020, about 60,000 people experienced post-acute covid symptoms for more than three months. In Sweden, a survey in September 2020 estimated that about 100,000 people experienced post-acute covid symptoms for more than 10 weeks.
Frequently reported symptoms include persistent coughing, moderate fever, general fatigue or exhaustion, shortness of breath, chest pain, heart palpitations, headaches, concentration problems, muscle pain, digestive problems, skin rashes and metabolic symptoms.
The exact cause of these persistent symptoms is not yet clear; cardiological (heart), neurological (nerves), pulmonary (lungs), renal (kidneys) or metabolic factors are suspected to play a role and may be triggered by the viral infection or the immune response to it. Repeated occurrence and subsiding of the symptoms is also frequently reported.
Some affected persons, including young people from around 30 years of age, report significant restrictions in their everyday life, such as exhaustion after climbing stairs or extended walks, as well as psychological effects such as despair or depression.
One to two months after coronavirus infection, symptomatic Swiss army recruits (median age 21 years) still showed a reduction of up to 20% in their maximum lung performance.
Post-acute covid is more frequent in younger rather than older people and in women rather than men because their immune response to the viral infection is stronger (and may be too strong).
Initial studies found involvement of the heart muscle (myocarditis) in a considerable proportion of mild and moderate covid cases. It is also known that even in apparently mild covid, some limited lung inflammation can occur in about 50% of cases. People with persistent chest pain or other persistent or new symptoms are therefore advised to consult a doctor for an assessment.
The so-called post-viral syndrome or post-viral fatigue is already known from other viral infections, including severe influenza (flu). The involvement of the heart muscle is also known from strong and pandemic influenza. The occurrence of post-acute covid is therefore not surprising or unusual, but it is nevertheless quite widespread and must be taken seriously.
Many people affected by long covid report a slow, wave-like improvement of symptoms, but an evidence-based medical prognosis is not yet possible at present. In any case, British doctors are predicting that there will be important public health questions related to “long covid”.
On the other hand, German lung specialists and Swiss heart specialists reported significant regeneration within three months even in previously hospitalized covid patients. British doctors reported that 75% of hospitalized patients still exhibited symptoms after three months, but with most patients improving and showing no permanent lung tissue damage.
In order to avoid post-acute covid completely, infection with the virus must be avoided. If a symptomatic infection does occur, early treatment options should be discussed with a physician to prevent progression of the disease. For the large majority of the population, covid nevertheless remains a comparatively mild and short-term infection.
Below is an overview of medical and other articles about post-acute long covid.
- Management of post-acute covid-19 in primary care (British Medical Journal, August 2020)
- Long term respiratory complications of covid-19 (British Medical Journal, August 2020)
- Covid-19: Impact of long term symptoms will be profound (BMJ, August 2020)
- US CDC study on Covid-19 symptom duration among outpatients (CDC, July 2020)
- Three quarters of patients report long-term effects of coronavius (Bristol Univ., 08/20)
- Covid-19 infections leave an impact on the heart (StatNews, July 2020)
- New Insights into How COVID-19 Causes Heart Damage (Biospace, August 2020)
- Cardiac Involvement in Patients Recovered From COVID-2019 (JACC, May 2020)
- COVID-19 patients suffer long-term lung and heart damage (EurekAlert, Sept. 2020)
- Covid-19 Recovery Awareness Project (C19RecoveryAwareness.com)
- The lasting misery of coronavirus long-haulers (Nature, September 2020)
- Thousands of people say they are suffering from lingering symptoms of COVID-19 months after testing positive (Business Insider, September 2020)
- Three Months In, These Patients Are Still Ravaged By Covid’s Fallout (WSJ, July 2020)
- COVID-19 Can Last for Several Months (The Atlantic, June 2020)