Vaccines are distributed across the world and we desperately need them if we are to successfully control some our most deadly infectious diseases. But they also require vast sums of money and expertise - on the part of academic institutions and private companies - to develop, manufacture and ultimately, dispatch worldwide. They thus have the power to save lives and rapidly divide opinion, with governments at odds with some individuals over the way that vaccination may or may not infringe on their rights.
This fact that we are so intimately affected by these medicines means that they impose a number of ethical implications for us as a species, like: Who has to get the vaccines? How much do you charge for them? In the event of an outbreak who gets it first? Is it right to make a profit out of them?
Lucky there's an excellent website (http://www.vaccineethics.org) with great resources explaining some of these more delicate points and supplying us with informed briefs, resources and commentary. Plus it comes from the guys at the University of Pennsylvania Center for Bioethics - so it will be well researched and most importantly independent; here's a list of their programs, so see for yourself. This organisation is primarily funded by the Greenwall Foundation, which is focused on the development of understanding of bioethics.
If you're interested in the role of ethics in vaccination and how vaccine manufacturers, governments and individuals can work together to employ vaccines worldwide, focus your reading on this site.