Thank you for sharing, and I'm sorry to hear about your mother and your struggles.

At present, I haven't come across any studies examining if the shingles or other vaccines can slow the progress of dementia once it has developed. A randomized clinical trial would be needed to investigate this before the shingles vaccine can be considered as a treatment for dementia or VaD.

About the herpes zoster on the chest, i believe it's a typical shingles. And based on a 2023 meta-analysis I cited in the article, typical shingles (localized to the skin) do not increase the risk of dementia.

But VZV reactivation may still occur, giving the possibility of developing herpes zoster ophthalmicus (HZO). And HZO can raise dementia risk because the virus can reach the brain at this stage.