Participants who were previously vaccinated with 90 g of unadjuvanted Vietnam vaccine were randomly assigned to receive 3.75 g of avian influenza Anhui vaccine with or without MF59 adjuvant , stratified by 1 vs 2 previous doses ( 1 dose : n = 18 with MF59 and n = 17 without ; 2 doses : n = 19 with MF59 and n = 18 without ) .