Ask your mom why she thinks she is in need of the vaccine at this time? Is not having the vaccine stopping her from doing things she wants to do today? What does she think will change when she gets the vaccine? Still has to wear a mask and social distance, so what changes? It's not about convincing her not to get it as much as it is listening to why she thinks now is the time? If she's been isolated, get her out back into as normal activities as she is comfortable doing even if she wears the mask. It's a hard place to be, if you talk her out of it and she gets sick you will bear that, if she takes it and she gets sick you will bear that too. In the end she has the right to choose. Pray and best wishes.