In contrast to known regimens where pandemic-associated antigens are given 3-4 weeks apart for immunisation, according to the invention two doses of a pandemic-associated antigen are administered to a human 1 week apart, 2 weeks apart or 6 weeks apart. Thus the invention provides a method for immunizing a human, comprising steps of: (a) administering to the human a first vaccine comprising antigen from a pandemic-associated influenza virus strain； and then 1/2/6 week(s) later, (b) administering to the same human a second influenza vaccine comprising antigen from the pandemic-associated influenza virus strain.
