The immune system includes billions of specialised blood cells, known as white blood cells, and their products, such as antibodies. These cells are located throughout the body and are integral in developing immunity from infection and disease.
Immunity is a state of protection that occurs in your body when you have been vaccinated or have had an infection and recovered.
Before vaccines, the only way to become immune to a particular disease was to actually get the disease and, with luck, fully recover from it. This is called naturally-acquired immunity.
In the process of acquiring natural immunity you may suffer symptoms of the relevant infectious disorder. This means you risk the short-term and long-term complications of the disease, which can be quite serious or even deadly. In addition, during certain stages of the infection, you may be contagious and pass the disease on to family members, friends, or others who come into contact with you.
Getting a disease is a far more dangerous way of developing naturally-acquired immunity than vaccination. The benefits of vaccination far outweigh minimal risks associated with it.
Vaccines help the body develop immunity by imitating an infection without illness. Vaccines work by stimulating your body’s immune system to produce T-lymphocytes and antibodies.
Sometimes, after receiving a vaccine, the imitation infection can cause minor symptoms, such as fever and fatigue. Such minor symptoms are normal and should be expected as the body builds its immunity. The chances of more serious adverse reactions are very low.
After immunisation, you have a much higher chance of being protected against the disease than if you were not immunised.