UAE, Aug. 25 -- As soon as the Adam family returned from their fun-filled trip to Europe, their joy was soured when their youngest family member, four-year-old Katy, came down with high fever and chills. It started with the little one and soon all three kids in the family, the older Mary and Tim in their preteens, were down with fever.

It was a week before school reopening and their GP said they had come back with a fresh strain of influenza. Tina, their mother, had to extend her leave to care for her sick children, and that ruined everyone's holiday mood.

What happened with the Adam family is pretty much the case with many families returning from vacation. Flu is in the air, and last year's flu vaccine is ineffective against new strain...