The invention relates to an influenza viruses hemagglutinin protein as a vaccine antigen against influenza viruses, in particular to a protein being a fragment of H5 hemagglutinin from highly pathogenic avian influenza virus (HPAIV) H5N1 strain, expressed in a bacterial expression system. The protein according to the invention is a potential ingredient of an anti-HPAIV H5N1 vaccine, administered to chickens parenterally or through mucous membranes in the presence of adjuvants. The object of the invention is also a method of obtaining the vaccine protein.
