With the advent of “Freedom Day”, one of the largest concerns medics, journalists and policymakers have had is whether it will increase instances of long Covid.

This describes when symptoms of Covid-19 last for more than 12 weeks after infection, whether they’re severe or mild. Here is a summary of some of the facts we know about long Covid so far, and the research taking place to understand it more.

How many people have long Covid?

The latest data from the Office for National Statistics indicates that around 1.8 million Britons have suffered from long Covid.

What are the symptoms of long Covid?

Dr Ron Daniels, CEO of the UK Sepsis Trust and an ICU doctor, says that “symptoms can broadly be grouped into three areas: cognitive dysfunction, commonly described as brain fog; secondly, physical sequelae, most commonly fatigue; thirdly, psychology sequelae, ranging from the mild up to and including PTSD.”

Surveys indicate that there could be hundreds of symptoms of long Covid, ranging from tiredness, shortness of breath, heart palpitations and changes to taste and smell, to insomnia, hallucinations, hearing and vision changes.

More recently, a 13-year-old girl spoke to the media about her experiences with long Covid, which included struggling to walk due to “COVID toes”, whereby one has discoloured, swollen feet.

How is it identified?

Currently there is no official test for long Covid and it is a “diagnosis of exclusion”. This means that doctors try to rule out other possible causes for the symptoms, such as diabetes, thyroid function or iron deficiency.

Speaking about this process, Dr Raghib Ali, a Clinical Epidemiologist at the University of Cambridge and an Honorary Consultant in Acute Medicine at the Oxford University Hospitals NHS Trust, tells me that exact diagnosis “is very difficult because there’s no control group to compare (long Covid) to”. He adds that an ONS survey helps clinicians to identify the condition, which “asks what people’s symptoms are now and then asks whether they attribute it to having had Covid in the past, and some do.”

In the future, researchers are hoping they can develop a blood test for the condition within six to 18 months. Imperial College London has found a pattern of unusual antibodies in the blood of a small number of people with long Covid, which could help scientists to identify more cases.

Are its symptoms similar to anything else?

Daniels tells me that some of the symptoms of long Covid overlap with other conditions, due to the serious treatment that many patients have undergone:

“Long Covid is neither surprising nor necessarily unique”, he says. “We’ve known for over a decade that survivors of any critical illness – in other words, those people severely ill enough to require hospital and intensive care admission, have symptoms which are similar to those of long Covid persisting for a year or longer. One Scandinavian study among working age adults admitted to intensive care with sepsis, for example, showed that only 57 per cent were back within 12 months.

“Even for those with relatively minor symptoms, fatigue and breathlessness can persist for many weeks afterwards. The general trajectory, though, is one of improvement.”

He adds that:

“What might be different in long-Covid is an increased likelihood of pulmonary fibrosis and myocarditis, but we do see both conditions occurring following critical illness with sepsis.”

What causes long Covid?

There are a number of hypotheses around what causes long Covid. One is that the virus encourages people’s immune systems to overreact, meaning they attack not only the virus but their own tissues.

Research from Cambridge University indicates that there’s some truth to this idea; it showed that there’s an immunity molecule present in sufferers of long Covid – suggesting that the symptoms are a result of the immune system “not shutting off properly”.

Another theory is that parts of the virus remain within the body, becoming dormant and then reactivated (this happens in herpes, for example). 

Over time, we can expect more of these theories to be tested as researchers look into the condition.

Who’s most at risk from long Covid?

Research seems to suggest that it becomes more likely with age, and that women are more likely to say they’ve said it (3.9 per cent) versus men (3.9 per cent).

It’s worth noting that in more vaccinated countries, it will be harder to get accurate data on who is most susceptible to long Covid (a good thing, incidentally), due to the jab’s protective effects.

How huge will its impact be on the NHS?

Ali tells me that: “the numbers are very large… So that is a huge burden, particularly on primary care (the GP). Most of these people won’t come to the hospital sector, because they’re not sick enough to need hospital treatment, but for primary care it’s a significant burden.”

And Daniels has a similar view: “Irrespective of the terminology and discussions around whether or not long Covid is unique is the long-term human and fiscal impact. If 43 per cent of working age adults are unable to return to work within 12 months following their illness, then the potential impact upon productivity and the economy is huge.

“If these people often go on to require re-hospitalisation, then clearly the burden on the NHS will be significant.

“We know from studies from UCLH and University Hospitals Leicester around a third of people with a previous admission with Covid-19 end up readmitted within about five months. 

“This, together with the fact that the symptoms of long Covid are likely to persist for six to eighteen months in around one quarter of patients, suggests that the short-term burden on the NHS will be significant. It’s unclear at this stage the impact long-term on the NHS as it’s too premature to say with precision how long these sequelae will last.”

Already, ONS statistics suggest that almost four in 10 said this had negatively affected their ability to exercise and three in 10 said it had negatively affected their work.

Current research

The National Institute for Health Research, a government agency which funds research into health and care, has recently allocated £19.6 million to 15 new projects in UK universities.

Researchers will look at organs affected by long Covid, such as the brain, lungs and muscles – as well as determining what treatments work best on long Covid, from drugs to rehabilitation and recovery work. One of the projects involves over 4,500 people.

Current treatments

In England, 89 specialist long Covid assessment centres have been set up, with similar clinics expected to open in Northern Ireland.

In Scotland and Wales, patients are referred to different services by their GPs, depending on what symptoms they have.

So far, it’s reported that around half of people with long Covid had an improvement in their symptoms after having a vaccine.

Medics have also been encouraging sufferers of long Covid to manage symptoms and gradually increase their activity, but there will also be a formal clinical trial into drug treatments. One study is trying to see whether aspirin and anti-histamines can help, for example.

Either way the £19.6 million funding should give researchers a big push for diagnostics and management tools.