While many people recover from Covid-19 without further problems, some report having long-term health problems. A large range of symptoms are reported by these sufferers, for varying periods after the infection. Symptoms typically fall into four groups.
Types of Long Covid
Post intensive care syndrome (PICS)
Critically ill patients can suffer a range of health problems after a long time in hospital. This can include muscle weakness, and anxiety or another mental health problem. They may also have memory problems, which can affect whether they can return to work.
Post viral fatigue syndrome (PVFS)
Similar to problems following enteritis or rubella, fatigue and 'brain fog' may make it difficult to concentrate or remember things.
Permanent organ damage (POD)
The lungs and heart, and also liver and pancreas, may have permanent damage.
Long-term Covid syndrome (LTCS)
This group report 'floating' symptoms which mean they do not fit into the other three groups. They suffer illness linked to one part of the body (e.g. respiratory system, brain, cardiovascular system and heart, kidneys, gut, liver or skin), which later abates, but then new symptoms arise in a different part of the body.
Why does this happen?
Latest: A small study (at Stellenbosch University, South Africa) comparing blood collected from 11 people with long Covid and 13 healthy individuals found that those with long Covid have a large amount of tiny clots of inflammatory molecules trapped in their bloodstream. These blockages have the potential to disrupt the body's ability to distribute oxygen and vital nutrients, which could explain - or help to explain - the most common symptoms of fatigue, headaches and breathing difficulties. Some of the trapped molecules contain clotting proteins such as fibrinogen (helps the body to make clots to stop bleeding) and alpha(2)-antiplasmin (helps prevent blood clots from breaking down). Under normal conditions, the body maintains a balance of clotting and anti-clotting material to help the body reduce blood loss after injury, and preventing clots from growing too large and restricting oxygen flow. High amounts of alpha(2)-antiplasmin stuck in the blood mean the body's ability to break down clots is severely reduced. Other recent studies have also highlighted that the body's clotting system could be involved, while Covid itself has been linked to clotting disorders during the initial infection. More research with larger samples is needed to confirm these findings, and research to identify the type of treatment for the problem.
There are three possible reasons, and long covid may even be a combination of these.
- Direct damage by the virus. For example, the heart and lungs can be permanently damaged, which could explain prolonged shortness of breath and chest pains.
- It is even possible that the virus could hide in some body tissues, and continually reactivate; some studies are looking into this possibility.
- Inadvertent damage that the body can do when it responds to the virus.
Long Covid is less common than first feared.
Initially it was unclear how many people might be affected, nor how long symptoms might last and whether there might be permanent damage. It it is possible to have serious Covid-19 symptoms and not experience long-term syndromes, and for those with mild cases to develop one of the syndromes.
The UK Office for National Statistics (ONS) has been monitoring this, by testing people at random which ensures that the comparison between Covid sufferers and non-sufferers is good. Additionally they carry out long-term follow-ups of those with long covid. Their latest (September 2021), large and comprehensive analysis suggests that one in 40 (2.5%) people with coronavirus has symptoms lasting at least three months.
Those most likely to suffer long-term (at least 3 months after infection) health conditions are:
- Women aged 35 to 69
- Those aged 50 to 69
- People with high levels of virus in their body when testing positive.
