Fatigue, cognitive issues or pain are some of the typical symptoms of long Covid. These symptoms also occur in the general population where there has been no prior infection with the coronavirus SARS-CoV-2, some possibly more frequently due to increased mental stress during the pandemic. This highlights the importance of assessing the prevalence of long Covid symptoms, not just for those who report an infection but also for control subjects without infection. Data from the Swiss Corona Stress Study now enables this comparison.

More than 11,000 people from all over Switzerland took part in the fourth survey, conducted in November 2021 as part of the Swiss Corona Stress Study and led by Professor Dominique de Quervain. In addition to the data on increased mental stress during the pandemic that has already been published, the researchers asked about the presence of a range of physical and neurological symptoms over the two weeks running up to the survey. 744 people stated that they had tested positive on a PCR for SARS-CoV-2 nine months or more (on average 362 days) prior to the survey (98 percent of whom were not admitted to hospital).

Long Covid symptoms for those infected versus control subjects

Several symptoms occurred more frequently among those who had previously tested positive for SARS-CoV-2 than for SARS-CoV-2-negative control subjects (figure 1). The group of control subjects was selected to match the group of SARS-CoV-2-positive people with regard to sociodemographic data such as age, gender or education as well as vaccination status and preexisting mental health conditions.

The most pronounced differences between the two groups of people occurred for the symptoms of loss of taste/smell, rapid physical exhaustion and fever. These symptoms occurred much more frequently in the group of SARS-CoV-2-positive people, regardless of their age or gender. There were other symptoms, however, such as gastrointestinal complaints, which showed no differences between the groups.