There are many individuals who have immune systems that function far differently than the norm.  Some have overactive immune systems, while others have suppressed immune systems that do not function at the level of their peers. There are many different medical conditions that result in an underactive or overactive immune system.  Several medications can trigger an immune response that can be temporary (e.g., during the use of the medication) or permanent (i.e., alter the immune system). You can locate additional information on job accommodations for suppressed immune systems from JAN’s A to Z by disability.