About Long COVID

For long-term complaints after corona, the English term 'Long COVID' is often still used. Long means here: 'long-term'. In the Netherlands, the association with the organ lung often leads to misunderstandings. After all, many complaints relate to other parts of the body. The WHO now speaks of post-COVID-19, because the long-term complaints occur after an infection with COVID-19 ('post' means 'after'). Other terms that circulate are PASC (Post acute sequelae of SARS-CoV-2 infection) and PCS (post-COVID syndrome). We mainly use the term post-COVID.

Common complaints

The most common complaints are: severe fatigue, forgetfulness, brain fog, inability to concentrate, headache, muscle pain, shortness of breath, chest pressure, palpitations, poor sleep, blurred vision, loss of taste and smell. But specific symptom clusters are also common, such as post-exertional malaise (PEM) en postural orthostatic tachycardia syndrome (POTS) an expression of dysautonomiaIn addition, patients may also suffer from idiopathic mast cell activation syndrome (MCAS)In total there are over 200 symptoms described.

It is not possible to indicate exactly how many people have post-COVID. This has to do with the number of complaints and the lack of registration of these patients. From research it has now become apparent that 1 in 8 people who have been infected have long-term complaints. In the MIT report is based on 450.000 patients, of which 90.000 patients with serious long-term complaints. This also includes children and young people.

More than 32.000 people have reported to C-support with complaints that last longer than three months.

Possible risk factors have now been defined that increase the chance of developing post-COVID symptoms:

• Female gender
• Severe acute illness or previous hospitalization due to COVID-19
• People of an older age
• People who smoke
• People with obesity
• People with a chronic condition
• People with an autoimmune disease
• People with previous Pfeiffer's
• People with Q fever
• People with ADHD
• People with type 2 diabetes
• People with chronic hives
• People with connective tissue disorders such as rheumatism
• People with allergic rhinitis (chronically inflamed nasal mucosa)
• People of Hispanic or Latino descent
• Returning to work too soon after a COVID-19 infection may also be a risk factor due to insufficient recovery and balance.

One-third of people with post-COVID appear to be healthy and free from chronic conditions prior to infection.

* source review in Nature (English) and Post-COVID knowledge bundling of the IVM and C-support

Figure available from: Davis, et al. (2023) Nat Rev Microbiol.

Much is still unknown about post-COVID, which is why many scientists are conducting research. 5 theories have been described that indicate what could be going on in the body with post-COVID complaints. These are increasingly being proven in various (international) studies. In addition, more and more connections are being found between various post-infectious conditions. Think of Q fever, ME/CFS, Lyme or sepsis, all diseases with long-term complaints after an infection.

Five theories*

1. Persistent infection
   Remains of bacteria or viruses remain present in various organs for a long time or perhaps permanently, which means that the illness does not stop.
2. Disturbed balance in the intestines ('dysbiosis')
   Own bacteria form an important balance in the body. A new parasite, bacteria or virus (infection) can disrupt the delicate balance between the various own intestinal bacteria types (colonies) which causes a process of inflammation. In some cases, this inflammation remains active in the intestinal tissue.
3. A hyperactive immune system ('disruption')
   The immune system is confused and immune cells in the body are incorrectly programmed and can attack the body's own cells (autoimmunity). The body continues to fight the foreign invader with or without reactivating underlying diseases, including (often harmless) infections suffered earlier in life.
4. blood vessels
   The vessel walls can be damaged by the virus, which can cause an inflammatory process in the small blood vessels. This inflammation can cause these small capillaries to become blocked by 'micro clots'. This can cause poor circulation in the blood vessels, which results in less transport of nutrients and oxygen. This can cause damage to nerves and muscles.
5. Dysfunctional signal processing in the brainstem and/or vagus nerve
   The neurological signal transmission in the nervous system ensures a balance in the dampening and activation of organs and regulatory systems. Due to the toxicity (direct harm) of the virus on the nerve tissue, this system in the body is considerably disrupted. Often, neurological complaint patterns emerge over time.

* source review in Nature (in English)

Much is still unknown about post-COVID. More and more research is being done both in the Netherlands and internationally. A complete overview of all studies is still lacking. PostCovid NL does have a selection of published studies on their website. website.

Below are some interesting links:

• Report Knowledge bundling of ongoing (inter)national research post-COVID
• Report knowledge agenda biomedical research post-COVID
• Public version report knowledge agenda biomedical research post-COVID
• Report on constituency consultation post-COVID
• Research consortium Long COVID Foundation