When an antigen enters your body, it triggers an immediate response from your immune system after recognizing the presence of a foreign substance to develop antibodies or immunoglobins, which are proteins that are produced to neutralize the threat of the foreign substance. When the germs or antigens from a virus or disease enter your body without a vaccine, your body is unable to act quickly enough to prevent you from getting sick. However, your body keeps a record of those specific germs so that, should you recover, your immune system will be able to neutralize the invading virus before it makes you sick. With vaccines, a trace of the virus is introduced to your immune system which is weak enough for your immune system to neutralize without your getting sick, and strong enough for it to develop a detailed memory of it should that virus affect you in the future. Vaccines enable you to develop protection from a disease without getting sick from it first. Moreover, by protecting you from the disease, vaccines also protect the people around you from acquiring the disease from you. As such, vaccines provide our society with herd immunity, which is necessary for the prevention of disease outbreaks. For this reason, the government has made vaccinations a mandatory prerequisite for children before they attend school. While this is controversial for some, it is a measure that is put in place for the safety and health of everyone.