In this phase II , open-label study , healthy participants aged @ to @ years ( median @ years ) were randomised ( @:@:@:@ ) to receive two single doses of the AS@A-adjuvanted vaccine ( @xH@N@-AS ) or the non-adjuvanted vaccine ( @xH@N@ ) , or two double doses of the AS@A-adjuvanted vaccine ( @xH@N@-AS ) or the non-adjuvanted vaccine ( @xH@N@ ) , @ days apart .