Being immunocompromised means your immune system cannot fight infections as well as it should. This weakened defense happens when your body has trouble making or using the cells and proteins that protect you from germs. People with compromised immune systems face higher risks from infections that healthy immune systems usually handle easily.
Your immune system can become weakened for many reasons. Some people are born with immune problems. Others develop them from medical treatments like chemotherapy or from diseases like HIV/AIDS. Organ transplant recipients take medications that intentionally weaken immunity to prevent rejection. When your immune defenses are down, common viruses and bacteria can cause serious illness.
Certain infections become particularly dangerous when immunity is low. Cytomegalovirus, or CMV, is one example. Most healthy people carry this virus without problems. But in immunocompromised individuals, CMV can cause severe diseases affecting the eyes, lungs, liver, and digestive system. Understanding your immune status helps you take steps to stay healthy and catch problems early.