Why are some diseases more common than others?

The common cold, and other viruses that don’t typically get past our upper respiratory tract, reinfect us not necessarily because they mutate rapidly, but because our body doesn’t usually produce many antibodies against these pathogens in the first place, said Mark Slifka, an immunologist at the Oregon National Primate Research Center.

Why do people only get some diseases, like chicken pox?

For many diseases, if you catch them once, you will never catch them again. Measles is a good example, as is chicken pox. When these diseases make it into your body, they start reproducing.

Why do we develop immunity to some diseases but not others?

Whether or not we develop immunity to a disease often depends on our antibodies, which are proteins we produce in response to infection. Antibodies are one of the body’s most well-known defenses: They coat invading cells and, in the best case, prevent those invaders from hijacking our cells and replicating.

Why do some diseases last longer than others?

For diseases that don’t fall into either of these categories — meaning they don’t mutate rapidly and they generally prompt a strong immune response — immunity tends to last much longer.

The common cold, and other viruses that don’t typically get past our upper respiratory tract, reinfect us not necessarily because they mutate rapidly, but because our body doesn’t usually produce many antibodies against these pathogens in the first place, said Mark Slifka, an immunologist at the Oregon National Primate Research Center.

For many diseases, if you catch them once, you will never catch them again. Measles is a good example, as is chicken pox. When these diseases make it into your body, they start reproducing.

For diseases that don’t fall into either of these categories — meaning they don’t mutate rapidly and they generally prompt a strong immune response — immunity tends to last much longer.

Whether or not we develop immunity to a disease often depends on our antibodies, which are proteins we produce in response to infection. Antibodies are one of the body’s most well-known defenses: They coat invading cells and, in the best case, prevent those invaders from hijacking our cells and replicating.