How do presently available human flu vaccines contribute to averting an influenza pandemic with avian flu virus H5N1?
• Available vaccines reduce the risk that humans at high risk of exposure to the bird virus might become infected with human and avian viruses at the same time. Such dual infections give the avian and human viruses an opportunity to exchange genes, possibly resulting in a new influenza virus subtype with pandemic potential. • Vaccines produced for routine use in protecting humans during seasonal epidemics of influenza now contain attenuated H5N1 virus strains. They offer protection against human infection with the H5N1 avian virus. • “a” and “b” are true. • “a” and “b” are false.
