If you are concerned that Bieber fever is spreading like wildfire, then you should be extra worried about a more mature pandemic with a strain that has mutated so many times there is little hope for a cure. It's New Kids on the Block fever, and it seems to infect women ages 27 to 40. Proof of the madness this pyrexia can cause was found at Thursday and Friday night's NKOTB concert at Radio City Music Hall.

Kathy Marcus, 33, had traveled from Philadelphia to see what would be her seventeenth NKOTB show. She had made each of the boy band members a bedazzled T-shirt. On the back, it read, "Who Loves You? Kathy."

She went back to the stage door, where a body guard accepted the shirts and promised to give them to the guys. This happens a lot. The band gets hundreds of home-made T-shirts and jerseys at each performance.

One woman nearly fainted at the site of Donnie Wahlberg striding into the theater, not incognito enough behind dark sunglasses. (Memo: Don't ask Donnie why he wears said sunglasses indoors during an interview, he gets super prickly.)