What’s the difference between pandemic and seasonal flu?
Influenza pandemics are caused by the emergence of a virus that is “novel” (brand new) or radically different from flu viruses that have spread in the past. Because people have little or no resistance to the new virus, and there is no vaccine ready-made to match the new virus, a pandemic results in more severe illness and more death than the common flu we are used to. Seasonal flu outbreaks are caused by small changes in common influenza viruses. Even though these viruses may change slightly from one year to the next, many people have some immunity. Because similar flu viruses have been around in the past, vaccine can be made to match as closely as possible the flu virus that is expected for the next flu season – before the flu season starts.
