When swine flu was first identitified it sent the world into a panic, then the World Health Organisation declared it a pandemic.
The H1N1 virus, as it came to be known, has since spread to 206 countries and overseas territories around the globe.
More than 6,700 people have died, and over 70 million vaccines have been distributed.
As winter sets in across the northern hemisphere, Dan Nolan looks into whether those vaccines safe or not.
