How do vaccines protect us from infection and why is it important that lots of people are vaccinated?

Vaccines contain a safe form(weakened or small sample, a dead sample) of a disease causing micro-organism.The white blood cells produce the antibodies to destroy the invading pathogen.The memory cells can then make antibodies again very quickly to protect against further attacks if you encounter the pathogen later.Herd immunity means that it is unlikely that a person with a disease would come into contact with an unvaccinated person limiting the spread of the disease and makes it easier to contain outbreaks.