Wait a minute. I can't follow your logic here. Yes, you are right ((somewhat) that no one knows how long vaccine immunity will last" but what does that have to do with not wanting the vaccine because you already had Covid? And you are also somewhat correct that you do have some immunity after infection. However , how do you know if it will last 3 months, 6 months or longer? How will you know when it's gone? The fact is that we don't have a test for public use that is accurate enough to market so it's not like we can monitor it ourselves. Your elderly aunt or anyone else may have a side effect because they didn't know they had Covid recently before getting the vaccine. These folks can have an exaggerated inflammatory response and if they are physiologically aged and fragile, that's a problem. Fortunately you are retired and can lay low forever, but the question would be more complicated if you were still doing patient care. If anyone came to my house and told me they weren't vaccinated, I wouldn't let them in because I have a small house and couldn't stay far enough away and Delta is in my community. Good luck with that post-Covid immunity. If you were sick enough to have pneumonia it is likely to last longer since uou were so sick.