Question: How come some peoples immune systems are weaker than others?

Kylie Belchamber answered on 21 Jun 2016:

So the immune system is not something that we are born with, it has to be made. You get some protection from your mother after birth, but after that your body has to produce immunity against the things it comes up against. So every time you are infected with a bacteria or a virus, your body will produce antibodies (little molecules that can remember an infection) against it, so that next time you are exposed to the same bacteria/virus, your body remembers it and can fight it quicker, meaning you won’t get sick, or you won’t get as sick as someone that has never been exposed before.
So we need to get exposed to lots of things as a child so that our immune systems can be built up. People that play outside a lot usually have better immune systems than those that dont. This has lead to the ‘hygiene hypothesis’,which states that people that are too clean – shower a lot, use a lot of disinfectants, dont go outside much, are too clean and so their immune systems have not built up enough. It is better for us to be exposed to dirt every now and then!
So this could be one reason why some peoples immune systems are weaker. Other things can effect it though – you can be genetically more likely to get asthma or eczema, and also how healthy we are can effect it. People that are stressed, eat badly and dont exercise have weaker immune systems, so if you want to boost yours, eat well and go play in the garden!

I hope that helps 🙂