Yesterday, the NY Times had this article about a shingles vaccine. Shingles is caused by a virus- the same as chicken pox (varicella-zoster from the herpesviridae family!). People with shingles typically have signs of rashes and nerve pain. It can be treated with an antiviral drug but once you get it, it stays with you and can show up again in times of stress.
The shingles vaccine uses a strain 14xs stronger than the chicken pox vaccine. It is supposed to either prevent shingles or reduce complications in those who had shingles. However, it is only administered to people who are 60 and above and have had chicken pox.
Check it out the article