How does vaccination work?
Vaccines contain either parts of microbes (bacteria or viruses) or whole microbes that have been killed or weakened so that they don’t cause disease. When a person is vaccinated, these harmless versions of the microbes enter the body, where they stimulate the immune system to react as if a real infection had developed. The immune system makes antibodies to these microbes that “remember” a virus or bacterium should it be encountered again. That way, the body can fight off the real microbe quickly if it enters the body in the future. After getting a vaccination, it generally takes 10 days to 2 weeks for the body to build up immunity to a disease. We usually think of vaccines as the shots we were given as kids. But not all vaccines are shots — very occasionally, some are given orally (by mouth) or in other forms like nasal sprays.
