For most people, Covid-19 is a mild illness they fully recover from, but some people are left struggling with symptoms for months, including chronic fatigue, ‘brain fog’ and breathlessness.
Sufferers of what’s know as ‘long Covid’ say it’s had a debilitating effect on their lives, with some virtually bed-bound and others having been unable to work since March.
People are reporting a wide variety of symptoms, beyond the official NHS definition of Covid, and many say they’ve felt unsupported. But as the pandemic has unfolded, there’s been recognition – research suggests one in 20 of those who get the virus suffer for more than eight weeks, and that 60,000 have symptoms for more than three months.
NHS England has now set up more than 40 specialist clinics for those with ongoing problems, with NHS chief executive Sir Simon Stevens recently describing long Covid as “already having a very serious impact on many people’s lives and could well go on to affect hundreds of thousands”.
The questions of why people suffer for longer or whether everyone will fully recover from this novel illness have been riddled with uncertainty.
We spoke to Professor Frances Williams, who is part of the team at King’s College London (KCL) overseeing the Zoe Covid Symptom Tracker app study, which has produced findings about who is most at risk of long Covid. With over 4.4 million app users, their latest research focused on data from 4,182 who consistently reported their health and tested positive for Covid through swab PCR testing.
What are the symptoms of long Covid?
There is no official medical definition or list of symptoms shared by all patients – two people with long Covid often have very different experiences. However, the most common are crippling fatigue and breathlessness.
Others symptoms noted include: headaches, a cough that won’t go away, low grade fever, muscle aches, hearing and eyesight problems, loss of smell and taste, gastrointestinal upset, rashes and hair loss.
Mental health problems reported include depression, anxiety and struggling to think clearly.
For many the illness can follow a remitting (getting better) and relapsing (getting worse) pattern.
Who is more likely to suffer longer?
The KCL team found that older people, women and those with a greater number of different symptoms in the first week of their illness were more likely to have longer lasting effects.
Weight also plays a role, with people developing long Covid having a higher than average BMI.
The researchers also found that asthma is a risk factor, although there were no clear links to any other underlying health conditions.
Why is being female a risk factor?
The findings that risk of long Covid increases with age is perhaps not totally unexpected. As we get older, our immune system weakens, making us more vulnerable to infections of all types. Long Covid affects across all age groups, but was found to be just over double in the over 70s (affecting 22 per cent) compared to 18-49 year olds (affecting 10 per cent).
What was more surprising was the discovery women are 50 per cent more likely to suffer longer term than men (but until around the age of 60, when their risk level became more similar), given that we know men have a higher chance of having severe Covid and of dying of the disease.
Females aged 50-60 are at greatest risk of developing long Covid, and KCL say the menopause could be the reason.
“We do see quite a marked increase in long Covid in middle aged women,” said Professor Williams. “That’s in keeping with similar conditions like post viral fatigue, which also affects women more. Women in midlife have a great deal of symptoms and I suspect this partly reflects the hormonal changes that take place at that time, the reduction of oestrogen. But further research is needed, which is why we’re applying for more research funding.”
Why is having a great number of symptoms an indicator of longer illness?
Having more than five different symptoms in the first week was one of the key risk factors found. Somebody who had a cough, fever, fatigue, and diarrhoea, and loss of taste for example, would be at higher risk than somebody who had a cough alone.
There’s no clear answer as to why, says Professor Williams. But her team have a theory about the biological reaction is happening in ‘long haulers’. Ongoing symptoms are thought to be the immune system’s response to the SARS-CoV-2 virus, rather than the virus itself, often through facilitating inflammation.
“What generally happens when a virus enters cells, through the nose or the mouth, is the body checks if it has already made antibodies to defend against it. If it hasn’t, it mounts a T cell response. These can attack virus-infected cells and help trigger the production of antibodies by B cells.
“But for some people the immune system goes haywire, a chain reaction is set off and it causes what’s known as a ‘cytokine storm’, which is what we’ve seen in people severely ill with Covid in hospital.
“T cell responses could also help to explain why some people recover fairly quickly from Covid, but others suffer after-effects for months.”
Professor Williams says viral load – the amount of virus in an infected person’s blood – could play a role too. “For example, studies looked at ENT surgeons who were exposed to people coughing and spluttering early on in the pandemic when we didn’t really know what was going on. Those doctors had a very large dose of virus, and got lots and lots of symptoms, and were really quite sick.”
Why is having a higher BMI more risky?
We know overall, that excess weight is a major risk factor for for serious Covid illness. Simply speaking fat tissue causes inflammation
Professor Frances Williams
“We know overall, that excess weight is a major risk factor for for serious Covid illness,” said Professor Williams. “People who have a raised BMI are walking around in a pro-inflammatory state. So they have elevated levels of these chemical messengers that I’ve already referred to. So it may be something to do with that, and it may be that the virus goes and hides in in adipose tissue. Simply speaking fat tissue causes inflammation.”
Does not needing hospitalisation mean you won’t suffer long term damage?
The term long Covid is being used to refer to anyone who is having ongoing issues, whether they needed hospitalisation or they initially experienced only mild symptoms and managed these at home. The National Institute for Health Research says it’s unclear if all sufferers are experiencing the same phenomenon given the varied, multisystem symptoms reported and suggests long Covid could be four different syndromes.
The agency says that it’s not accurate to assume that someone who has been seriously ill with the virus will be more affected long term than those who fall into a low risk category.
A study last month found that young and previously healthy people with ongoing symptoms of Covid-19 were showing signs of damage to multiple organs four months after the initial infection.
Preliminary data from the first 200 patients to be screened suggests that almost 70 percent had impairments in one or more organs, including the heart, lungs, liver and pancreas, four months after their initial illness.
However, the Coverscan researchers caution that doesn’t prove that organ impairments are the cause of people’s ongoing symptoms, and the data hasn’t yet been peer-reviewed.
Preliminary findings from a separate, small study of 58 patients who were hospitalised with Covid-19 similarly found that two to three months after the initial infection, 60 per cent had abnormalities in the lungs; 29 per cent in the kidneys; 26 per cent in the heart; and 10 per cent in the livers of 10 per cent of patients, as well as tissue changes in parts of the brain.
But Professor Williams said we can’t yet draw conclusions. “We don’t really know the answer to this. If you’ve been sick enough to be in an intensive care unit, people rarely walk away without some organ damage.
“The app study is working with the healthier people, because they’re the ones accessing the app, whereas my hospital colleagues only see the really sick people. We need a study that brings the full spectrum of illness together.”
Will sufferers make a full recovery?
The many similarities between long Covid and ME (myalgic encephalomyelitis)/Chronic Fatigue Syndrome has generated medical debate. The exact cause of ME is unknown, but, a viral trigger is strongly suspected, and exercise can easily trigger an intensification of symptoms in both illnesses, at least in a subset of people with long Covid.
With ME, there is wide variation in recovery times: some people recover in less than two years while others remain ill after several decades. According to the ME Association, those who have been affected for several years seem less likely to recover; full recovery after symptoms persist for more than five years is rare.
You can’t really predict accurately how long people are going to have long Covid for. It’s a wait and see type thing
Professor Frances Williams
But experts point out that fatigue can also be triggered by ongoing inflammation or reduced oxygen supply caused by heart or lung damage, so identifying whose fatigue is triggered by what is challenging.
Professor Williams said she “expects there to be parallels” between the two conditions. “There was a big enough debate about ME before we even knew about Covid of course, it’s pretty contentious area.
“But I think it’s very reasonable to expect there to be similarities. There is the same sort of cytokine reactions implicated in both illnesses.
“Lots of people are seeing improvements but this is a nasty, nasty bug in some people. In our fast moving world that we expect to get better very fast but of course biology is not always like that. We’ve known for decades that if you have glandular fever, you can be you can be ill for months or even years. You can’t really predict accurately how long people are going to have long Covid for. It’s a wait and see type thing.”
Are long haulers infectious to others?
Professor Williams agrees with the general thinking that patients are very infectious in the first week to 10 to 14 days after developing symptoms, but most people are not infectious afterwards despite ongoing problems. A few people have been shown to be ‘long viral shedders’.
Ongoing symptoms are most likely caused by the body’s response to the virus persisting even after it’s inactive.
“You have to look at your symptoms,” she said. “If you have a high fever, that’s a clear sign that your immune system is active and fighting something so you may well be a shedder. If you’re coughing and spluttering, again, you’re probably likely to be shedding virus. If anybody has had a re-emergence of fever, it’s a possibility that they could have caught it again and they should isolate. But there have been very, few case reports of people having it twice.”
Is it safe for people with long Covid to have the vaccine?
As with many so things Covid-related, we’re in uncharted waters. None of the Covid vaccines have yet been tested on people who have already had the virus – let alone those still having ongoing symptoms.
“I can’t see a reason why a vaccine should make them worse,” said Professor Williams. “Research is still ongoing into how strong that protection is and how long it lasts, and so it would be sensible to have it.”
What can people do to reduce their risk of long Covid?
There’s nothing we can do about our age or sex. Getting to a healthy BMI, through a healthy diet and exercise is a no-brainer.
The role of vitamin D in serious cases of Covid has been identified. One recent study found more than 80 per cent of hospital patients struck severely with the illness had a deficiency, which is linked to an increased risk of upper respiratory tract infections. A lack of vitamin D is thought to be common in the general UK population.
The NHS is now recommending supplementation and is providing it free in England if you’re at high risk (clinically extremely vulnerable) of Covid. People need to apply before 4 January.
“The long Covid clinics are checking people’s levels,” she said. “We know vitamin D is important for the immune system. So it would be important to supplement, especially through the winter months and we are all staying indoors more and not receiving the UV exposure we normally do.”
Where the NHS says there is currently not enough evidence to support taking vitamin D to prevent or treat coronavirus, Professor Williams says it’s sensible to supplement.
“The long Covid clinics are checking people’s levels,” she said. “We know vitamin D is important for the immune system. So it would be important to supplement, especially through the winter months and we are all staying indoors more and not receiving the UV exposure we normally do.”
Long Covid clinics in England
NHS England launched more than 40 long Covid clinics last month to help thousands of patients.
These have brought doctors, nurses, therapists and other NHS staff under one roof to offer physical and psychological assessments of those experiencing lasting symptoms.
Costing £10m to fund, ten sites are in the Midlands, seven in the North East, six each in the East, South West and South East, five in London and three in the North West.
These services will be accessed via referral from a GP or other healthcare professional, allowing doctors an opportunity to rule out any other possible underlying causes for symptoms, such as suspected stroke, lung cancers or respiratory conditions.
There are calls for clinics to be set up in the rest of the UK.
This article was updated on 9 December at 11.36am to make clear the NHS is now recommending vitamin D supplements for the clinically vulnerable.
