There's been a few studies that found increase in shingles as the chicken pox vaccine became more widespread in the US, actually. With the usual caveat that correlation is not causation.
If the vaccine became available in the 90s, and it was given to kids mostly, those people are 40 at most now, so how is the increase in shingles measured? More cases when younger? More older people getting it?
Thinking about it within this context doesn't make much sense.
How was the study done?
If the vaccine became available in the 90s, and it was given to kids mostly, those people are 40 at most now, so how is the increase in shingles measured? More cases when younger? More older people getting it?
Thinking about it within this context doesn't make much sense.