Anyone who has had chicken pox is at risk regardless of age. The anti viral medications work if taken within a certain amount of time that shingles is diagnosed. My cousin did that and that is what she would do again if she ever got shingles again. The vaccine is not 100% effective. Currently it is for people 60 years and older. There can be side effects.

http://www.cdc.gov/shingles/vaccination.html