This sin is on the holder of the card and not on the medical staff. They are doing a service and it is not their sin where the people pay them from!

I want to work by a muslim gynecologist, but i have to work with health insurance cards and as I know every insurance is involved with interest (In Germany everyone needs to have an insurance). I often think that maybe I will be sinning if I start working there with these cards, because I could also keep on looking for another job, is this right or can I start working there?