Every vaccine has its own specialty. The vaccines against influenza were created especially against H1 and H3 influenza viruses, but genes of viruses are constantly changing. In recent years, human cases of SARS or H5N1 avian influenza have been found every winter and spring, which may even influence safety of the nation. Consequently, with the high vaccination rate of Common Flu, precautions will be taken effectively.
Furthermore, the situation of H5N1 avian influenza among the poultry farms in many Asian countries has become more and more serious. A new strain of the H5N1 avian influenza virus may emerge when people are infected by both common influenza and avian influenza, which may bring about an influenza pandemic if people are not protected with the antibodies. Therefore, it is necessary to emphasize vaccines against "Common Influenza."