In this phase II , open-label study , healthy participants aged 61 to 88 years ( median 68 years ) were randomised ( 3:1:3:1 ) to receive two single doses of the AS03A-adjuvanted vaccine ( 1xH5N1-AS ) or the non-adjuvanted vaccine ( 1xH5N1 ) , or two double doses of the AS03A-adjuvanted vaccine ( 2xH5N1-AS ) or the non-adjuvanted vaccine ( 2xH5N1 ) , 21 days apart .