Part of me thinks that they are keeping her isolated until her jubilee. The jubilee is such a big deal celebration that I think they want to ensure that it happens and will take great care with her health. At the same time, she’s not the type of person to shy away from her duties. She looked good on camera during her video appearances.
Makes me nervous, but I also thought (and hoped) that maybe they just want her to have a low key few weeks/months. She did look a little unsteady the last couple of times we saw her and she was using a walking stick. It may be that it is her back that has been bothering her all this time.
It will be interesting to see how Christmas goes - who, when and where!