A large British study showed more clearly than ever how many people have long-term complaints after Covid-19. The vast majority of adults recover from the disease within two weeks, but 1 in 13 people (7.5 percent) still report complaints after twelve weeks, and 1 in 20 (5.2 percent) still have them after a year. still. With a quarter of a million participants surveyed repeatedly since May 2020, it is the largest study to date into the long-term health effects of Covid-19. The results of researchers from Imperial College London appeared on Tuesday in the scientific journal Nature Communications.
How large is the group of people who suffer from long-term complaints (long covid, in other words post-acute sequelae of Covid-19, PASC), is still unclear. The percentages found in previous studies vary widely, including due to a lack of a good definition of long Covid, small and poorly designed study groups, and because good control groups were often lacking, such as groups of people who have not had Covid-19.
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Groningen researchers published the first study that did have good control groups last year. They found that 1 in 8 people (12.7 percent) had long-term complaints after Covid-19 after three months.
Poverty is a risk factor
The percentage now found is lower. This is probably because the British researchers looked over a longer period of time, during which all virus variants have circulated, from the original virus from Wuhan to Omikron.
The British study shows that the risk of long Covid is greater in people who have been infected with the original virus. Those who became infected when Omikron was distributed were 88 percent less likely to still have complaints after three months. This is because people already had much more immune defenses thanks to previous infections and vaccinations, the researchers suspect.
The risk of long Covid is also higher in women, in people who had severe symptoms or an underlying condition at the onset of the disease, and the risk increases with increasing poverty.
It is striking that all groups of participants report many complaints. Complaints such as mild fatigue, difficulty thinking or concentrating and joint pain occurred in 55 to 67 percent of people with long Covid, but also in 15 to 36 percent of people who never had Covid-19, and in 21 to 38 percent of the people who recovered within four weeks – this could be due to another flu-like illness, for example. But the specific complaints, loss of smell or taste, shortness of breath, severe fatigue and difficulty thinking and concentrating, occurred 9, 7, 6 and 5 times more often in the long Covid group than in the other groups. Mental complaints and exhaustion after physical or mental exertion (post-exertional malaise, PEM) were also more common in people with long Covid.
The authors find it encouraging that a third of people who still have complaints after three months have recovered within a year.
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