English-language reports of published studies on CMV infection in critically ill immunocompetent patients were identified through November 2008 by cross-referencing the following medical subject headings (MeSH) keywords and text words: cytomegalovirus, immunocompetence, critical illness, intensive care units, intensive care, reactivation, sepsis, and shock. Databases searched included PubMed, EMBASE, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials. Bibliographies of original articles were manually reviewed for additional articles. Non-Englishlanguage reports were also identified in PubMed using the same keywords in order to supplement our search.