DH is part of the Oxford trial, 77, obese, high blood pressure and diabetes in remission. i volunteered but was not selected. We obviously do not know whether he got the COVID vaccination or the control one, he remains as fit and healthy as ever - and he has had two jabs in the last 3 months vaccine trials .
I do not think your wife is paranoid, but there are so many unsubstaniated to deliberately untrue rumours being circulated about the safety or otherwise of these of vaccines in general and COVID in particular. Perhaps your DW has heard a some of the misleading conspiracy theories and is concerned that you may become ill. I can understand that.
She may also think that being part of these trials means that you will be exposed to the virus itself. You will not. The challenge aspect of the trials, where people are vaccinated then exposed to the virus islimited to healthy people under 35 and they are taken into hospital for the whole experiment.
Why not ask her why she thinks as she does. Let her talk without interruption and then do not scoff at her concerns but address each one with facts and a cup of tea or coffee, even some nice biscuits.