There are some things you never fully appreciate until they are gone, such as your sense of smell and being able to walk upstairs without gasping for breath.
And that’s what millions are facing as a result of long Covid.
Thanks to the vaccines, there are signs we are finally getting on top of the virus. But we face another challenge in long Covid, with symptoms such as loss of sense of smell, breathlessness, extreme tiredness and brain fog, which in some people will last for months, possibly years.
I know quite a few people who either have or had long Covid, including one of my sons, Daniel, who spent nearly six months unable to smell anything; and a friend, Sarah, who is in her 50s and a year after getting Covid can still barely walk upstairs without pausing for breath.
Another friend, Louise, who is in her late 50s, lost her sense of smell and found that foods she normally enjoys tasted absolutely revolting.
As many as two million people in the UK could be affected, according to a recent study by Imperial College London.
Surprisingly, this also revealed that while men from ethnic minority groups are most at risk of dying from Covid if they catch it, women, particularly middle-aged white women, such as Sarah and Louise, are most likely to get long Covid.
Researchers at Cambridge University are looking at whether giving statins or a blood-thinning drug to patients when discharged from hospital helps long-term outcomes
What causes long Covid is still something of a mystery, although we know the virus can attack almost every organ, from your lungs to your heart, kidneys and brain.
One recent study found that people with long Covid reported more than 200 different symptoms, covering ten of the body’s major organs.
With the loss of smell, the most likely explanation is that the virus attacks nerve cells in your nose.
The prolonged fatigue and breathlessness is probably also the result of an attack on nerve cells, in particular nerve cells that form part of the autonomic nervous system, which regulates gut function, heart rate and breathing, among other things.
Evidence for this comes from a surprising source: fitness trackers.
Many, like me, use these to monitor our heart rate, physical activity and sleep.
The companies that sell these devices also store this data and now some smart researchers from the Scripps Research Institute in California have realised this kind of data, anonymised, could be used to compare what happens in the long term to people who have had Covid with those who have had other respiratory diseases, such as flu.
The researchers recruited 37,000 people who shared the data from their fitness trackers, as well as providing their symptoms and Covid test results via an app.
Using the details from 875 people, the researchers found that after several months, those who’d had Covid were sicker for longer, with a prolonged and striking rise in their heart rates (which remained elevated, on average, for over two months) and increased fatigue and breathlessness.
If you are one of the many people affected by long Covid, what can you do about it?
There are lots of trials testing different treatments — at Glasgow University, for example, they are recruiting people who are overweight or obese and have long Covid for an 850-calorie a day, rapid weight-loss trial.
As well as reducing cholesterol, statins are powerful anti- inflammatory agents, while blood-thinning drugs should prevent clots, a common complication of long Covid that can lead to strokes and heart damage
Previous research has shown that carrying a lot of excess fat raises the risk of dying if you get Covid, and makes long-term complications more likely.
Losing weight has been shown to reduce post-Covid fatigue,
