How big a risk is long Covid?
Of all the questions about Covid, some are most concerned by those over long Covid – when people have lingering symptoms for more than 12 weeks.
A key question is how common it is, with some of the earlier studies suggesting alarmingly high figures. One source of confusion is that long Covid is used as an umbrella term for people who have had different experiences of the initial infection. The term includes people who got so sick from Covid they needed weeks on a ventilator in hospital – who would be expected to take a long time to recover – as well as people who had a flu-like illness.
Even when just considering those who were not hospitalised, another pitfall is that some early studies surveyed only people who had been infected, on symptoms such as fatigue. But it is very common for people to have fatigue whether or not they’ve had Covid.
Better-designed studies that compared symptom rates in people who were infected versus those uninfected give lower prevalence figures, typically of around a few per cent.
But giving a single figure for the prevalence of long Covid can also be misleading, as the term encompasses a wide spectrum of symptoms of varying impact.
The long Covid symptoms that get the most attention are fatigue and breathlessness, with media coverage focusing on people who are most severely affected, such as those who are left unable to work or are even bed-bound. In fact, the long-lasting symptom most clearly linked with Covid after a mild initial infection is
loss of smell and taste, according to a large Israeli study.
Another reason for optimism is that long Covid rates have been falling over time. Fewer people reported long-lasting symptoms as the pandemic went on, probably because they developed partial immunity to the virus, and the Omicron variants, which arrived at the end of 2021, may also be less virulent.
Research is ongoing to find out how common it is for someone to get lasting illness after a mild Covid infection in 2024, when most have partial immunity by now from vaccination and past infections. As more studies are done, they will add to the picture – but probably won’t stop the arguments.
