Vaccines, sometimes called immunizations, needles or shots, are medical substances that create immunity to particular diseases. Vaccines are injected via a hypodermic needle or given orally by mouth. There are many different types of vaccines, but all aim to do the same thing, reduce the risk of contracting potentially deadly diseases such as polio and chicken pox. Due to the availability of vaccines, diseases such as small pox have been wiped out.
How Do They Work?
Vaccines work because our body has a natural defense system called the immune system. The immune system recognizes foreign bodies such as viruses and bacteria and creates antibodies to destroy them. Once your immune system has had contact with a particular virus or bacteria it knows how to protect the body against it. Vaccines use the body’s ability to do this to help protect us against diseases that may otherwise be deadly. Vaccines contains part of the virus or disease and when injected stimulate the body to create antibodies to fight and neutralize the disease.
There are three ways that vaccines are developed. Firstly part of the disease or virus is weakened so that when it is given it does not cause the full disease. For example, in the chicken pox vaccine the virus is weakened in the laboratory by stopping its ability to replicate quickly. The virus will only replicate enough times for your body to create an antibody to fight it. The second way vaccines are created is with deactivated virus cells. These viruses have been neutralized by a chemical agent. However, the presence of the virus, even in its inactive state, will trigger an immune response. These vaccines usually have to be given multiple times before they are effective and include vaccines for polio, hepatitis A and influenza. The third way to develop a vaccine is to extract a selected part of the virus, the antigen, and use this to create an immune response in the body. These types of vaccines also require multiple doses before you gain lifelong immunity.