However, some say there may be many more long COVID sufferers in the UK than reported. One study by researchers in Norway suggests that 60 per cent of those with COVID-19 had persistent symptoms<\/a> six months later.<\/p>\n We spoke to Dr David Strain<\/a>, a lecturer at the University of Exeter Medical School and medical advisor for Action for ME<\/a>, a charity supporting patients with a similar post-viral illness, myalgic encephalomyelitis (ME). He explained everything science currently knows about long COVID.<\/p>\n Strain says there is no textbook definition for long COVID, and the term can be used to refer to two separate conditions.<\/p>\n One is known medically as \u2018ongoing symptomatic COVID\u2019 and it occurs from week 4 after catching COVID-19, to week 12. \u201cThat\u2019s where your symptoms of COVID-19 disease are continuing beyond that initial acute phase,\u201d said Strain.<\/p>\n Then there\u2019s \u2018post-acute COVID syndrome\u2019 which is typically from 12 weeks onwards. However, these cut-off time frames are beginning to fall away, as many patients across both types use the term long COVID.<\/p>\n There are several theories as to how the SARS-CoV-2 virus causes long-lasting symptoms, but the mechanism is likely to be different depending on how a patient\u2019s long COVID presents, said Strain.<\/p>\n In those who are hospitalised with COVID-19-induced pneumonia, or spend time in the intensive therapy unit (ITU), Strain explained that this may in itself cause long COVID.<\/p>\n \u201cAny pneumonia that puts you in the hospital ITU for a few weeks will leave you with symptoms for quite some time,\u201d said Strain.<\/p>\n Some long COVID patients will have damage to their blood vessels<\/a>, caused by the coronavirus.<\/p>\n \u201cUnlike most other lung viruses, COVID-19 has a real preference for affecting your blood vessels,\u201d said Strain. \u201cSo, we can see small clots appearing. If they affect the lungs, you get what\u2019s called a pulmonary embolism. If the clots affects the kidneys, you can get kidney disease. If it affects your brain, you get strokes.\u201d<\/p>\n However, some long COVID patients were never in ITU, and don\u2019t have any blood vessel damage. For this group, it\u2019s harder to know why they have persistent symptoms.<\/p>\n One theory relates to the path that COVID-19 takes to get into our bodies. All viruses have a way to get into our cells, but COVID-19 uses an entry point that is part of our body\u2019s defence system. Making it inactive could lead to long-term effects.<\/p>\n All viruses have to use a pathway to get into cells, and COVID-19 uses an enzyme called ACE2.<\/p>\n \u201cIf you have any source of infection in your body, your body flushes essentially a poison through the system and it gives your own cells the antidote to that poison. Then anything that\u2019s not \u2018you\u2019 gets poisoned. But it\u2019s the ACE2 enzyme that creates your antidote.\u201d<\/p>\n It could be that when COVID-19 impairs ACE2, our bodies are flooded with poison designed to rid us of the disease, but our inability to make the antidote leads us to develop long COVID.<\/p>\n Another possible cause of long COVID could be the presence of the virus in our bodies long after we\u2019ve tested negative for COVID-19.<\/p>\n \u201cSome researchers are asking whether there could be some virus hiding somewhere in the body in an immuno-privileged tissue, a place that your immune system can\u2019t get to,\u201d said Strain.<\/p>\n Strain believes the most likely place a virus could hide would be in our guts. Our gut isn\u2019t generally affected by our immune system, because there are good and bad bacteria and virus that live there to make up our microbiome<\/a>.<\/p>\n \u201cPeople who get long COVID do have a dramatic change in the make up of their microbiome. We see that, and it\u2019s useful to know because it means that we can start looking at that tissue to see if the gut the place where the problem is. Though it could be several things; it could be that the virus is living there. It could be that the virus just wipes out your healthy gut bacteria. Or, it could just be purely coincidental, and people have got long COVID have made diet changes because they\u2019re reaching for higher energy foods, and when your diet changes, so too does your bacteria change.\u201d<\/p>\n According to the January 2022 ONS data, the most common long COVID symptoms were fatigue, found in 50 per cent of patients; shortness of breath, reported by 37 per cent, and a loss of smell<\/a> (37 per cent) and loss of taste (28 per cent).<\/p>\n The ferocity of the symptoms can vary, and Strain said there can be a waxing and waning of peoples\u2019 illnesses.<\/p>\n \u201cSymptoms can vary from extreme, debilitating fatigue and malaise right through just some very mild symptoms. The classic symptoms that people are describing are fatigue, difficulty concentrating or what\u2019s called brain fog<\/a>, and then muscle weakness or muscle aches and pains, which we call myalgia.\u201d<\/p>\n One aspect of long COVID is what\u2019s called post-exertional malaise, which Strain describes as the tiredness and lethargy that is completely disproportionate to the exercise or activity undertaken.<\/p>\n Read more about long COVID:<\/strong><\/p>\n \u201cThat seems to be one of the hallmark features of the fatigue that people get. And the only place that we\u2019ve seen that symptom before is in chronic fatigue syndrome, or ME. So much so that a lot of people are saying that this entire group of patients with long COVID basically have ME<\/a>. Actually, a lot of people with ME are looking to long COVID research and saying maybe we\u2019ll finally start getting some answers.\u201d<\/p>\n Strain says that some people are also having symptoms such as hair loss, temperature changes, feeling feverish and diarrhoea.<\/p>\n \u201cA significant proportion of people are describing anxiety or difficulty focusing. That\u2019s really difficult to tease out [a cause], because if you\u2019ve had a very mild illness and then been left with a debilitating fatigue, it\u2019s understandable that you\u2019re going to be feeling depressed. You\u2019re effectively grieving for the fact that your body\u2019s not working three months later.<\/p>\n \u201cBut there are people who get disproportionate anxiety or neurological problems like mood alterations. Given that our mood is just a collection of neurones and hormones in the brain, there\u2019s no reason to suspect that the other dysregulations that are affecting the body aren\u2019t affecting the brain. Therefore, this is a manifestation of long COVID.\u201d<\/p>\n The NHS recommends<\/a> that people contact their GP if they are worried about any symptoms that have persisted for four weeks or more after having COVID-19.<\/p>\n While the symptoms of fatigue, muscle pain and shortness of breath are common in long COVID, they could be an indicator of an underlying illness.<\/p>\n \u201cThe main thing that we do in the clinic is make sure that there\u2019s nothing else [going on] that we do know how to treat. So, if we\u2019re getting people with severe palpitations, we start looking for other causes of palpitations or we try medications at work for palpitations. Some people actually have a syndrome called postural orthostatic tachycardia, for which we can test.<\/p>\n \u201cWe\u2019ve actually picked up a few things in people who\u2019ve come in for long COVID. A few patients who had under-active thyroid problems, a few new cases of diabetes or picked up. I saw one patient who actually had cancer and his haemoglobin had dropped, and that\u2019s why he was fatigued.\u201d<\/p>\n Currently, long COVID clinics test for other illnesses to rule out. However, scientists are looking for ways to test for specific damage associated with long COVID.<\/p>\n One study by researchers from universities across Cardiff, Manchester, Oxford, and\u00a0 Sheffield, showed that patients with long COVID seem to have problems with getting oxygen<\/a> into their cells.<\/p>\n \u201cOxygen isn\u2019t getting across the membranes as it should, and that\u2019s something that hadn\u2019t been shown before in long COVID patients or in any other disease, really. That suggests that the oxygen from the air isn\u2019t getting into the blood vessels, and that raises a whole lot of questions about why. Is it because the membranes aren\u2019t right? Have the blood vessels become occluded or are they just not transmitting? Is it a problem with the blood itself?<\/p>\n \u201cBut the fact that they can identify that there is a problem is a step in the right direction.\u201d<\/p>\n Some are also looking to see if there is a problem with long COVID patients\u2019 metabolism.<\/p>\n Our body turns the food that we eat into a molecule called ATP, which is a store of energy that can be released when needed. As we exercise, or do anything that requires energy, we begin to break down ATP. It then becomes something called ADP and a molecule called phosphocreatine.<\/p>\n \u201cMeasuring the amount of phosphocreatine and its ratio to amount of ATP can give you an idea of where your metabolism is and whether you\u2019re drained,\u201d said Strain. \u201cThis is something that\u2019s already been demonstrated in people with ME.\u201d<\/p>\n While those with long COVID as a result of being in the hospital ITU or due to blood vessel damage will have had symptomatic COVID-19, figures show that long COVID patients with predominantly ME-like symptoms might have had very mild, or even asymptomatic COVID-19.<\/p>\n \u201cVery often, the only time that these patients realise they\u2019ve had COVID is because they get antibody tests come back positive,\u201d said Strain.<\/p>\nWhat is long COVID-19?<\/strong><\/h2>\n
What causes long COVID?<\/strong><\/h2>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>What are the symptoms of long COVID?<\/strong><\/h2>\n
How do I know if I have long COVID?<\/strong><\/h2>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>Is there a test for long COVID?<\/strong><\/h2>\n
Can asymptomatic people get long COVID?<\/strong><\/h2>\n
How does the vaccine affect my chances of getting long COVID?<\/strong><\/h2>\n
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