World Immunization Week was implemented for the first time, involving over 180 countries and running 21-28 April 2012. The theme of the week —

Protect your world: Get vaccinated –  “aims to reinforce the importance of immunization and encourage people everywhere to vaccinate themselves and their children against serious diseases. It is also a time to recall that, in this rapidly globalizing world, disease outbreaks can affect communities everywhere.”

Additional coverage:

http://www.who.int/mediacentre/news/notes/2012/immunization_week_20120423/en/index.html