Question: Once you get a disease, are you immune to that disease in a short term time?

Sabrina Slater answered on 11 Jun 2020:

Hey Sasha. Good question 🙂

On the whole, the answer is yes! When your body comes into contact with the thing that causes the disease, like a bacterium, a virus or a fungus, it will recognise it as a foreign object and attack it. This is called “innate immunity” and happens within hours of infection. During the attack, specialised cells of the body rip the object to shreds and parade bits of it around for all the cells of your body to see. The body can then start making antibodies that specifically match to its shape.

Antibodies are like the body’s barcoding system. So when the cells of your body recognise an antibody with a barcode that doesn’t match its own natural barcode, it will attack the object! This is called “adaptive immunity” and protects people in the long term. This is because body is able to remember these barcodes, so that if in a few months or years time we see the disease-causing object again, we know how to attack it. Have you ever heard people say “you can’t catch chicken pox twice”? This is why 🙂

The drawback to this is that the body isn’t 100% effective at remembering all these different antibodies forever, so over time your immunity to something can fizzle away. There’s also a slightly different problem, when your body overreacts to these barcodes and starts attacking itself; this is called “autoimmunity” and is the basis of many disease, like arthritis and type 1 diabetes.
Hope that answers your question!