4.5.3 - Immunity and vaccinations

Immunity can be passive or active:

• Active immunity- The type of immunity you get when your immune system makes its own antibodies after being stimulated by an antigen. There are two different types of active immunity- natural and artificial. Natural is where you become immune after catching a disease, and artificial is where you become immune after you've been given a vaccination containing a harmless dose of antigen
• Passive immunity- The type of immunity you get from being given antibodies made by a different organism- your immune system doesn't produce any antibodies of its own. Again there are two types- natural and artificial. This is when a baby becomes immune due to antibodies it receives from its mother through the placenta and breast milk. Artificial is when you become immune after being injected with antibodies from someone else, e.g. If you contract tetanus you can be injected with antibodies against the tetanus toxin, collected from blood donations

Vaccinations to help control disease:

• While your B lymphocytes are busy dividing to build up their numbers to deal with a pathogen, you suffer from the disease. Vaccination can help deal with this. They contain antigens that cause your body to produce memory cells against a particular pathogen, without the pathogen causing disease. This means that you become immune without showing symptoms. If most people in a community are vaccinated, the disease becomes extremely rare. This means that even people…