Despite numerous descriptions of the infectious and noninfectious causes of IRIS, the overall incidence of the syndrome itself remains largely unknown. Studies to date are often retrospective and focus on specific manifestations of IRIS, such as tuberculosis-associated IRIS (TB-IRIS). In a large retrospective analysis examining all forms of IRIS, 33/132 (25%) of patients exhibited one or more disease episodes after initiation of ART [4] . Other cohort analyses examining all manifestations of IRIS estimate that 17-23% of patients initiating ART will develop the syndrome [32] [33] [34] . Another large retrospective study reported 32% of patients with M. tuberculosis, M. avium complex, or Cryptococcus neoformans coinfection developed IRIS after initiating ART.