Vaccination is based on the principles of immunology, which is the study of the body’s immune system. Vaccines are designed to stimulate the body’s natural defenses so that it can better protect itself from diseases. This is accomplished by introducing a weakened or killed form of the disease-causing microorganism into the body. The body recognizes the microorganism and mounts an immune response, producing antibodies that can protect against the actual disease.
Immune System Response
When a person is vaccinated, the body’s immune system responds by producing antibodies that recognize and fight the disease-causing microorganism. The antibodies bind to the microorganism, making it easier for the body’s cells to recognize and destroy it. Vaccines stimulate the production of these antibodies and help the body to remember the microorganism, so that if it ever encounters it again, it can mount a more rapid and efficient response.
Herd Immunity
Vaccines can also help to protect entire communities by creating what is known as “herd immunity.” Herd immunity occurs when a large proportion of the population is vaccinated against a particular contagious disease. This helps to reduce the spread of the disease, because people who have not been vaccinated are less likely to encounter an infected individual.
Safety
Vaccines are generally considered to be very safe. The World Health Organization (WHO) and other health authorities regularly review the safety of vaccines to ensure that they are as safe and effective as possible. The manufacture of vaccines is also subject to strict regulations, and only those vaccines that meet certain safety standards are allowed to be marketed.