Your blood is composed mainly of red and white cells, red ones carry oxygen and nutrition to all parts of body, white ones are defenders and scavengers of your body, during infection, they are immediately called upon to fight infection and clean up afterwards. These billions of cells work very hard and consequently they have quite a short lifespan, usually, only a few days.

Originally Immune System did not face as many problems, as it does in this day and age, now it has to cope with pollution, poisons, toxins, pesticides, herbicides and chemicals, in air that we breathe, food that we eat and water that we drink. As you will understand, immune system is fighting a huge battle, just trying to cope with all these attacks that are happening every day. Luckily for us, these cells can be generated very quickly, so with correct nutrition, it will not take immune system much time, to get back up to full strength.

When you have a vaccination, your immune system is given a copy of a specific disease, so that if system comes across disease again, memory cells in immune system, will know exactly what action to take, likewise, if you have had a disease before, they know what to do in event of reinvasion.