Patients who suffered Covid-19 symptoms for 12 weeks were worst affected by the disease in terms of their memory, attention, reasoning and processing speed, according to a study of 3,000 people.
Researchers from King’s College London found cognitive impacts of Covid could be detected nearly two years after the initial infection.
Professor Claire Steves, professor of ageing and health, said: “The fact remains that two years on from their first infection, some people don’t feel fully recovered and their lives continue to be impacted by the long-term effects of the coronavirus.
“We need more work to understand why this is the case and what can be done to help.”
The latest data from the Office for National Statistics estimated 1.9 million people in the UK - 2.9 per cent of the population - had self-reported having long Covid symptoms for more than four weeks after they were infected.
According to the ONS, 51 per cent of people reported difficulty concentrating - the second most common symptom of long Covid.
The NHS launched long Covid clinics in a bid to tackle the growing problem with data showing around 2,000, referred to clinics each month. Of those 23 per cent, according to data for June, were left waiting for more than 14 weeks for an initial appointment.
Earlier this month the British Medical Association published a survey of doctors reporting one in five of those with long Covid had been forced to stop work or significantly reduce their hours.
King’s College researchers looked at 3,000 patients who had Covid-19 in the UK, and asked them to carry out cognitive tests, over a time span of two years. Data found patients who had a quick or full recovery from Covid-19 reported no cognitive symptoms.
However, for those who experienced Covid-19 symptoms for more than 12 weeks after infection the impact on their ability to carry out the test was comparable to the effect of a 10-year increase in age.
Lead author Dr Nathan Cheetham, a senior postdoctoral data scientist at King’s College London, said: “Our findings suggest that, for people who were living with long-term symptoms after having Covid-19, the effects of the coronavirus on mental processes such as the ability to recall words and shapes are still detectable at an average of almost two years since their initial infection.
“However, the result that Covid had no effect on performance in our tests for people who felt fully recovered, even if they’d had symptoms for several months and could be considered as experiencing ‘long Covid’, was good news.”
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies