The immune system is the body's natural defense system that helps fight infections. An impaired immune system does not work properly and can't effectively protect a person against infection.
            Some conditions and medicines weaken or impair the immune system. These may include:
            
              - Substance use disorders or problems caused by quitting their use (withdrawal).
 
              - Certain diseases or conditions. Diabetes, cancer, HIV/AIDS, or conditions in which the body mistakenly identifies its own tissues as harmful (autoimmune disorders) are some examples.
 
              - Chemotherapy or radiation therapy.
 
              - Some medicines, such as corticosteroids or those taken to suppress the immune system after an organ transplant.
 
              - Surgery to remove the spleen (splenectomy).
 
            
           
         
        
          
            
              Current as of: October 25, 2024