Primary immunodeficiency disorders (also called primary immune disorders or primary immunodeficiency) weaken the immune system, allowing infections and other health problems to occur more easily.
Many people with primary immunodeficiency are born missing some of the body’s immune defenses, which leaves them more susceptible to germs that can cause infections.
Some forms of primary immunodeficiency are so mild they may go unnoticed for years. Other types are severe enough that they’re discovered almost as soon as an affected baby is born.