What are the symptoms of COVID-19 sequelae?
The after-effects of COVID-19 are not fully understood and there is no internationally accepted definition – so measuring how common it is or what symptoms it involves varies.
Guidance for health workers in the UK describes COVID-19 sequelae as symptoms that persist for more than 12 weeks after infection and cannot be explained by other reasons.
According to the NHS website, these may include:
- Extremely tired
- Shortness of breath, heart palpitations, chest pain or tightness
- Memory and concentration problems ("brain fog")
- changes in taste and smell
- joint pain
But patient surveys have uncovered dozens, if not hundreds, of other symptoms. A large study from University College London (UCL) identified 200 symptoms affecting 10 organ systems.
These include hallucinations, insomnia, hearing and vision changes, short-term memory loss, and speech and language problems. Others report gastrointestinal and bladder problems, menstrual bleeding, and changes in skin conditions.
Symptoms vary in severity, but many people are unable to perform tasks such as showering or memorizing words. However, these symptoms may also have other causes.
Research published by the ONS in September 2021 found that 0.5% of people who tested negative for coronavirus had at least one symptom that lasted three months, compared with 3% of people who tested positive.
How do I know I have long-lasting COVID-19 symptoms?
There is no standard test, and doctors first rule out other possible causes of symptoms.
People suspected of having the disease may first be tested for other issues, such as diabetes, thyroid function and iron deficiency, before receiving a COVID-19 diagnosis.
What causes COVID-19 sequelae?
Not sure yet. It may be that the initial infection sends some people's immune systems into overdrive, attacking not just the virus but their own tissues.
The virus itself entering and damaging our cells may explain some symptoms, such as loss of smell and taste, while damage to blood vessels may lead to heart and lung problems.
Another theory is that fragments of the virus may remain in the body, possibly dormant, and then reactivate.
This also happens with some other viruses, such as herpes viruses and the Epstein Barr virus that causes glandular fever.
However, there is currently not much evidence that this will happen with Covid.
It's likely that several different things happen to different people to cause such a wide range of problems.
Who has COVID-19 and how common is it?
That's hard to say for sure because doctors have only recently begun documenting long-lasting COVID-19 sequelae.
The latest ONS estimates suggest around 1.3 million people in the UK live with the disease. Of these, 892,000 (70%) were first infected with the virus at least 12 weeks ago, and 506,000 (40%) were infected at least a year ago.
The survey asked nearly 352,000 people to record their symptoms.
It shows that this condition is most common in:
- People aged 35 to 69
- female
- People with underlying conditions that limit daily activities
- People working in health and social care
- people living in poor areas
In April, the Office for National Statistics said around 1 in 10 people with coronavirus would develop symptoms that lasted at least three months.
But in September, it showed the ratio was one in 40.
The numbers will continue to change as more data is collected and will vary depending on the definition used.
Where are the children?
Children are less likely to contract Covid than adults and therefore less likely to suffer long-term Covid sequelae - but some still do.
However, in August 2021, leading experts said they were reassured by the scale of long-term coronavirus infection in young people after the world's largest study showed persistent symptoms were not as common as feared.
Some early estimates suggest that as many as half of all children infected with the coronavirus will develop long-term COVID-19 infection.
A team of researchers, led by the Great Ormond Street Institute of Child Health, looked at more than 200,000 positive cases among 11 to 17-year-olds between September 2019 and March 2020.
They believe 4,000 to 32,000 people are still showing symptoms 15 weeks later.
We don't know how severe the symptoms are, but there is little evidence that children are bedridden or unable to attend school.
But researchers stressed that the risk to young people was "not insignificant" and said it was vital that children receive the medical support they need.
Can vaccines help?
Some reports suggest that vaccinated people are less likely to be infected with the coronavirus over the long term.
First, vaccination can help prevent people from contracting the virus and developing long Covid.
It may also prevent the infection from "turning into" long-term COVID-19 sequelae, but this is not yet clear.
What treatments are available?
Similar clinics have opened in Northern Ireland, while in Scotland and Wales patients are referred to different services by their GP or other health professional depending on their symptoms.
There are currently no proven pharmacological treatments, and the main focus is on controlling symptoms and gradually increasing activity.
Research continues on how best to identify, treat and improve the lives of people with long-term Covid.
