To prepare the world for the next influenza pandemic, the WHO has advised national governments to develop pandemic preparedness plans. The production, distribution and administration of a pandemic influenza vaccine play a major role in such plans. Pandemic influenza vaccines would reduce spreading of the virus and the burden of disease in the population, like the risk of serious illness or death, very much like regular flu shots offer protection against seasonal influenza. However, the production of an influenza vaccine that matches the pandemic virus strain cannot begin until after the pandemic influenza virus has been identified, as shown during the H1N1 2009 pandemic. Since it may take up to six months to produce and market the first doses of such a vaccine, the pandemic influenza vaccine may not arrive in time.