LONDON (BLOOMBERG) - For about one million people across Britain, Covid-19 did not just go away. Instead it lingered, causing exhaustion, shortness of breath, cognitive issues and other health problems.
With England preparing to lift virtually all restrictions even as infections are surging again, scientists are concerned that the numbers impacted by what has become known as "long Covid-19" will climb much higher.
In a bid to understand more, Britain's National Institute for Health Research on Sunday (July 18) announced about £20 million (S$37 million) in funding for 15 studies analysing the causes of long Covid-19 and its physical and mental health impacts.
Britain's rapid immunisation campaign has fully vaccinated 53.2 per cent of the British population, according to Bloomberg's vaccine tracker, prompting the government to declare that the link between infections and hospitalisations has been weakened.
Prime Minister Boris Johnson says people must learn to live with coronavirus.
But millions still remain vulnerable, and those who have endured symptoms for weeks, months - or more than a year - say the long Covid-19 threat is being overlooked as policy makers focus on headline figures of cases, hospitalisations and deaths.
As the more contagious Delta variant spreads, other countries attempting to manage the next phase of their pandemic will likely find themselves facing a similar dilemma.
"When the government talks about opening up, there have been no references to long Covid-19," said Ms Christina Barratt, a 51-year-old former sales manager in Manchester who first experienced Covid-19 symptoms in late March last year.
Prioritising vaccination for vulnerable older age groups means a lower percentage of young Britons have had their shots in time for the ending of curbs. That concerns Ms Barratt.
"Young people feel invincible but this can really happen to anyone," she said.
Ms Barratt said she was bedridden for months after contracting Covid-19, at times so weak she could not roll over or move. Sometimes, she said, it felt like she was comatose even though she was awake.
During this time, Ms Barratt lost her job and has since faced new symptoms, including numbness, pins and needles and chronic fatigue.
For Ms Barratt, one of the biggest difficulties is communicating her plight to others, including doctors and even family and friends. "The illness becomes part of who you are," she said.
While the government has defended its plan, Health Secretary Sajid Javid said cases could reach as high as 100,000 per day and England's Chief Medical Officer Chris Whitty warned that there could be an increase in long Covid-19, especially in younger people.
Britain last Friday held out the possibility of restoring some restrictions later in the year.
Britain's strategy has been sharply criticised. More than 120 scientists co-signed a letter in the Lancet medical journal on July 7, warning that rising infections could leave hundreds of thousands of people with illness and disability "for decades to come".
International experts joined their British counterparts online to sound a further warning last Friday.
An estimated 962,000 people, or 1.5 per cent of the population, have experienced self-reported long Covid-19 symptoms in Britain, according to data from the Office for National Statistics published earlier this month. More than a third of those said they have suffered for more than a year.
Separately, an Imperial College London study published last month found that 38 per cent of people who caught the virus reported one or more symptoms lasting at least 12 weeks. Researchers estimated that, overall, more than two million adults in England may have had long Covid-19 so far.
The funding announced on Sunday will help explore the broad range of long Covid-19 symptoms, studying everything from the oxygen absorbed by the lungs to brain function to the level of care and support that should be provided.
The prevalence of the condition known as "brain fog" is one of dozens of symptoms that experts say justify calls for a national screening programme.
University College London's principal research fellow Dennis Chan pointed to the way viruses like Sars-CoV-2, the coronavirus that causes Covid-19, affect the brain.
"We have never seen anything like this in terms of the sheer scale," he said in a briefing with reporters.
Meanwhile, new cases of long Covid-19 seems to be on the rise. The ZOE Covid Study estimates there are currently 500 new cases of long Covid-19 a day in Britain among unvaccinated people.
"Vaccines have massively reduced severe infections and post-vaccination Covid-19 is a much milder disease for most people," Dr Tim Spector, lead scientist on the study and a professor of genetic epidemiology at King's College London said. "The main concern is now the risk of long Covid-19."