Your body has an amazing defence system with white blood cells as front-line defenders. They travel through the body in constant surveillance for invaders. Once an enemy is identified an attack is launched. Your immune system has a memory, and each invading pathogen is logged so it can be recognised and destroyed should it return. Look after your immune system. Make sure you get plenty of sleep, exercise, fresh air and a healthy, varied diet, full of the vitamins needed to keep your body’s defences in good working order.