NEW YORK (AP) — Two years ago, George Green got stabbing pain and bad blisters around his right arm. It was the worst case of shingles his doctor had ever seen."I said, 'Wait a minute, I had the vaccine! How come I got this?'" recalled Green, a 68-year-old engineer in Austell, Georgia, who got the shot seven years earlier.His doctor at Emory University, Dr. Sharon Bergquist, said about 10 percent of the patients she's given the shingles shot have come back with the disease years later.No vaccine is perfect, and it can take many years to find out how well a new vaccine works and how long it lasts.