Shingles.
Vaccine has been available for several years but it's expensive and many who likely would benefit haven't been getting it. For many, a cost issue.
Thing is - and I have no idea why - there has been a huge increase in the number of people getting shingles in the last six months to a year. No, no link so don't ask for one. Purely anecdotal and it may be confined to a single region. Still, about 1 in 5 of local folks over 70 have gotten shingles.
Local doctors intrigued but not enough to try to get any study going.
Bright spot: Those who had the vaccination tend to have smaller areas of blistering and it subsides much more quickly than in those who did not get the vaccine.
Go figure.