Germs and Your Immune System

Germs are tiny living things — bacteria, viruses, and fungi — that can get inside your body and make you feel unwell. They are so small that millions would fit on a full stop. Luckily, your body has a brilliant defence system called the immune system that fights them off day and night.

It helps to know the difference between the two main germs. Bacteria are tiny living cells that can multiply very quickly. Viruses are even simpler and smaller — they are not really alive on their own, so they sneak inside your cells and use them to make copies of themselves.

Your immune system has several layers of protection. Your skin is a wall that keeps most germs out. The mucus lining your nose and throat traps germs like sticky flypaper. If germs do get inside, white blood cells rush to attack them — they are the brave soldiers of your body.

Some white blood cells gobble up germs whole. Others make special proteins called antibodies that stick to a particular germ and mark it for destruction, like putting a target on it. Once your body has beaten a germ, it remembers how, so it can win even faster next time.

Vaccinations are a clever way to teach your immune system without you getting ill. A vaccine introduces a harmless piece of a germ so your body can practise making antibodies safely. If the real germ ever arrives, your immune system is ready and defeats it quickly.

You can help your immune system stay strong. Sleeping well, eating plenty of fruit and vegetables, and staying active all keep your defences ready. Washing your hands and covering coughs and sneezes stops germs spreading to you and to other people.