Table 3 Illustrative quotations for themes and statements derived from the interviews and focus groups

Perceptions of COVID-19 vaccination

One participant reported pronounced health symptoms and limitations in everyday life during the acute COVID-19 phase, despite having previously received a booster vaccination.

“I had for example […] a very, very severe course […] despite vaccination and despite a booster. […] I spent three weeks in bed, crawling on all fours to the toilet, which was really the highest of feelings. When I thought, ‘Okay, I’m starting to get better. I also tested negative’, I didn’t even make it down the stairs.” (F1, P4)

Several participants stated that they had not been vaccinated at the time of infection due to the state-established vaccination order.

“When I had it last year [COVID-19], it […] was just starting with the vaccination campaign and I was not yet in the prioritization stage in terms of age that I could have been vaccinated.” (I4)

Two participants reported that they did not make use of booster vaccinations for fear of negative effects on their long COVID complaints.

“I’ve gotten to the point where I don’t do it [get vaccinated a third time] because I’m afraid […] that I might not be able to think clearly if I get vaccinated again now.” (I3)

“I was vaccinated twice and I would never get vaccinated again.” (F2, P2)

The participants wished for scientific research on the question whether their symptoms could be a long-term consequence of the vaccination or whether there is an interaction between COVID-19 and COVID-19 vaccination that leads to long-term complaints.

“The question that’s developing for me right now from this is, can I attribute this [my symptoms] to the vaccination? Is this some late effect of the vaccination? I got boosted in December and […] I got COVID in mid-February. Or is that somehow the vaccine plus the disease, that that triggers something, some processes in the body, that that happens […]? […] Maybe we can find that out sometime.” (F2, P5)

One participant described her perception that non-vaccinated individuals with SARS-CoV-2 infection from her social environment had better health than her with vaccination.

“I can only reflect what I experience from my immediate environment. And that is just, those who were not vaccinated, they are feeling better now despite infection than me with vaccination.” (F2, P2)

Some participants were uncertain about the health benefits of COVID-19 vaccination for people with pre-existing long COVID. They expressed doubts about vaccination decisions al-ready made and about the future handling of this measure.

“Then I really asked myself ‘What did it [the COVID-19 vaccination] bring about, did it help at all now?’ So I really caught myself asking that, thinking to myself ‘If I hadn’t gotten vaccinated, would it have been better or worse?” (I13)

“I am now also skeptical about this vaccination. Well, I could maybe also say possibly it would have been much worse if I hadn’t been vaccinated, but so a bit of mistrust is already growing.” (I11)

Vaccination reactions after COVID-19 vaccination

Three participants experienced comparable symptoms following COVID-19 vaccination to those during the acute phase of COVID-19.

“I have to say about that, afterward [after the vaccination] I felt as bad again as when I had COVID. So, I could breathe so badly again. […] That went on for a few days.” (I3)

Two participants reported externally visible symptoms as a result of the vaccination.

“Because I had bruises all over my body after the first Biontech vaccination” (F4, P2).

“Then [after vaccination] the swelling started […]. Which was pretty blatant with swelling of the genitals, feet, hands, face.” (I7)

Two participants reported very poor health and heart problems following COVID-19 vaccination.

“I had heart problems after the booster vaccination, which meant I had also been in the hospital for heart muscle inflammation, at that time.” (I2)

“I had heart palpitations in November 2021, after I got two vaccinations shortly after each other, […]. I was really really bad since the second vaccination. In August 2021 I got the second vaccination, then I just dragged myself to work, then I came home and couldn’t do anything. All of that reminded me of when I had COVID and was just dragging myself around. Then I had something like long COVID, I was just broken and didn’t want to hear anything. […] Then I had these lapses, they had then done an exercise ECG on me and that’s when they found the heart palpitations.” (I9)

Two participants experienced a persistent deterioration in their health and long COVID symptoms after vaccination against COVID-19.

“I’ve also noticed through my booster vaccination […] how much worse my long COVID symptoms have become again.” (I5)

Rehabilitation experiences

Two participants perceived the combination of inpatient rehabilitation at the seaside and follow-up rehabilitation sports as helpful.

“I’ve been in rehab in the meantime, and it’s already done a lot of good for me. I was at the North Sea. […] After that, I also started doing rehab sports. I just notice that it does me good.” (I7)

The participants discussed the lack of focus of rehabilitation clinics on long COVID and the lack of experience of professionals in treating patients with this condition as possible reasons for this.

“I also just recently had a rehab that unfortunately wasn’t very successful, so it wasn’t that great. There were quite a lot of things started, but not finished unfortunately.” (F4, P1)

“Also relatively quickly sent to rehab […] to Borkum [an island in the North Sea]. It was still relatively early last year in summer [2021] […]. There was just a lot of lung training so that the lungs first get well again. But it has been found out that my lung has nothing at all […]. And the clinic was not specialized for long COVID. […] In retrospect, the sport I did was exactly the wrong thing. I did too much sport in that rehab.” (F3, P3)