Even as Covid cases continue to climb, the Government's plan to lift all remaining restrictions in a matter of days is still on track for a single reason: the vaccine has severely weakened the link between infections, hospitalisations and deaths.
Yet, amid the optimism, another concern has cast a shadow – the rising diagnoses of long Covid, the debilitating condition that leaves sufferers battling symptoms for months after being infected.
More than a million Britons are said to be living with lingering problems, from breathlessness to brain fog, and that figure could double by the end of the summer, say experts.
With no effective drug treatments yet discovered, there has been little hope for those living with the worst difficulties – until now.
In a world first, British scientists are set to explore giving long Covid patients monthly doses of the Covid vaccine, in an effort to combat the chronic condition.
In a world first, British scientists are set to explore giving long Covid patients monthly doses of the Covid vaccine, in an effort to combat the chronic condition. (Stock image)
The first stage of the study was given the green light on Friday: later this year, 40 long Covid sufferers will be offered at least two extra jabs.
Funding has been offered by several of the major vaccine developers, and if the pilot is successful the scientists involved have been told they can recruit thousands more patients.
Speaking exclusively to The Mail on Sunday, Dr David Strain, senior clinical lecturer at the University of Exeter Medical School, who will lead the trial, says the manufacturers are interested in funding the study after early research showed that long Covid symptoms were significantly reduced after patients had a jab.
Dr Strain said: 'Many saw a dramatic improvement within days of their jab. Their fatigue disappeared, they were able to walk further without feeling breathless.
'Some said it was the closest to normal they'd felt since they first caught Covid.
'In an earlier study we saw this lasted for about a month after the first dose, but then symptoms return.
'The same pattern was seen when people went for their second jab. We want to find out whether, over time, offering regular doses can make this change permanent.'
Scientists believe roughly one in ten people who catch Covid will suffer from prolonged symptoms.
These vary, but the most common include shortness of breath, muscle aches and problems with thinking and concentration – dubbed brain fog.
For many, their symptoms are yet to subside and, according to the Office for National Statistics, nearly 400,000 Britons say they have been experiencing symptoms since contracting the virus towards the start of the pandemic.
Doctors have struggled to treat the condition, despite the fact that in the past year the NHS has opened more than 80 specialist clinics to treat the rising number of patients.
The exact causes and processes that result in the majority recovering from Covid infection fully, while others do not, are still unknown.
Liliana Jackson (above), 16, from Sleaford, Lincolnshire, has suffered from long Covid since September 2020, when she tested positive for the virus
Many even argue it is a 'collection of syndromes' rather than one disease.
But recent research has suggested that Covid vaccines may be a highly effective treatment.
A paper published in the Lancet medical journal in May, authored by Dr Strain, which surveyed more than 900 long Covid patients, reported that more than half saw their symptoms improve after they received their first vaccine dose, and there was a particularly strong response in patients who received the Pfizer or Moderna jabs.
However, patients noted the positive change was temporary, lasting only a few weeks.
Dr Stain said: 'The plan would be to recruit patients whose symptoms are so severe their lives are severely limited by the condition. Those, for example, who can't go to work or pack their child's lunch in the morning because they feel so fatigued.
'We would offer them the jab at a long Covid clinic and they'd return for another the following month.
'The jabs cost roughly £15 a dose, and if it can get hundreds of thousands of Britons back to normality then it would be a very cost-effective treatment.'
The trial will be the first time in the world a Covid-19 vaccine will be used for any purpose other than protecting people against the virus itself.
At a time when vaccines are in short supply, it is expected to raise ethical questions.
But Dr Strain is clear the vaccines being used will not have been taken out of the supply chain. Instead, manufacturers have offered to provide 'outdated' jabs.
He said: 'Right now all the manufacturers are designing their second-generation vaccine. These will be designed to combat the Delta [Indian] variant, as well as the South Africa variant, which many worry is highly resistant to current jabs.
Liliana had her first vaccine dose in March, and after five days of feeling unwell with the typical side effects of nausea and aches, her symptoms suddenly improved
'Once new vaccines have been created, there'll be no need for the original vaccines, which were designed with the initial Covid variant in mind. These will be the vaccines we use in the trials.'
Long Covid patients can be roughly split into two groups.
The first comprises those who were hospitalised with serious Covid symptoms. These patients may have suffered serious damage to vital organs such as the lungs or heart. As a result, it can take months for them to recover.
This is, to a large extent, expected after severe illness.
However, doctors are more confounded by the other group of sufferers – those whose illness was initially mild but then lingered or even worsened.
These patients make up the majority of the UK's one million long Covid sufferers.
Professor Danny Altmann, an immunologist at Imperial College London, said: 'There is no real consensus yet on what is behind long Covid, though there are several theories.'
One is that symptoms are brought on by reservoirs of the virus which remain in certain areas of the body after infection.
A similar condition was seen during the 2014 Ebola outbreak in West Africa, where many who survived the deadly disease continued to experience illness for months. Scientists believe this was due to persisting low-level infections.
Recent studies in the US have found Covid cells in the gut months after infection.
Prof Altmann believes this may explain why vaccines can reduce long Covid symptoms.
He said: 'What we may be seeing is the jabs are giving the immune system an added boost, which allows it to reach the pockets of the body where the virus has been hiding.'
Another popular theory is that the virus destabilises the immune system – some studies suggest that Covid can affect the mitochondria, the power-house within cells which supplies them with energy.
Experts say this can cause the immune system to malfunction and attack healthy cells.
Similar mitochondrial dysfunction has been observed in patients with chronic fatigue syndrome, which shares many symptoms with long Covid.
Dr Strain believes this is the most likely theory, and argues the vaccines are, even temporarily, shutting off this overactive immune response.
He said: 'It's possible that, by focusing the immune system on the act of developing Covid antibodies, it can reset the cells which are misfiring. It's akin to turning a faulty computer off at the plug and
