There are many reasons for vaccinating, the most important of which is to prevent disease. Some of the diseases previously held at bay by immunization programs are coming back into developed nations. Click the link above for further explanation.
Read more about vaccine safety at the CDC website, including recommended schedules for receiving vaccinations.
To follow outbreaks, see ProMED_mail on Twitter, they link to news alerts and articles. Current alerts include Measles in New Zealand. Previous outbreaks have included Measles in the UK and U.S., H1N1 influenza, and plague (yersinia pestis).