Hi,
Maybe this will help. Same FDA site.

Should someone who has already had shingles use the vaccine, so that they don't get them again?

An episode of shingles boosts immunity to the virus so it is unlikely that persons who have had shingles will suffer from them again. The effectiveness of Zostavax in preventing repeated episodes of shingles has not been demonstrated in clinical studies.


In those who were vaccinated with Zostavax, but still developed shingles, the duration of pain was a bit shorter for them versus those who received a placebo. Specifically, the pain of those in the Zostavax group lasted on average for 20 days and for those who received placebo, it lasted for about 22 days. The severity of the pain did not appear to differ among the two groups.

It sounds like a real toss up.. nothing seems clear about the vaccine to me.