At month 24 , haemagglutination inhibition antibody seroprotection rates were 37.2 % ( 95 % CI 27.0 % to 48.3 % ) for 1xH5N1-AS , 30.9 % ( 95 % CI 21.1 % to 42.1 % ) for 2xH5N1-AS , 16.2 % ( 95 % CI 6.2 % to 32.0 % ) for 1xH5N1 , and 8.3 % ( 95 % CI 1.0 % to 27.0 % ) for 2xH5N1 .