Also, the Herpes family (hint: most of us have HSV-1), vide "Alzheimer's risk 10 times lower with herpes medication" https://news.ycombinator.com/item?id=17540094 and much more, https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que....

And "The effect of shingles vaccination at different stages of dementia" https://news.ycombinator.com/item?id=46164646 (yes, also the Herpes family).