Vaccinations are now considered a part of everyday life, but how do they work? This unit will help those with a background in biology understand the historical development of vaccination, assess the various types of vaccines used today, examine their production and explore the limitations that are placed on vaccination programmes. This study unit is just one of many that can be found on LearningSpace, part of OpenLearn, a collection of open educational resources from The Open University. Published in ePub 2.0.1 format, some feature such as audio, video and linked PDF are not supported by all ePub readers.