Pandemic Flu (Influenza A Virus H1N1) Swine Flu key chain

An influenza pandemic can happen when a novel flu virus emerges, such as a swine flu.

Swine flu is an influenza virus that usually affects pigs. However, just as the common, seasonal flu that affects humans is constantly mutating (as our immune systems and vaccines compromise weaker strains), swine flu is always trying to improve itself so that it can become more virulent, spread faster – and even associate with better company.