Thus, we identified a total of 13 studies that have described CMV infection in immunocompetent critically ill patients with sample sizes ranging from 23 to 237 (Table 1) [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] . These included nine prospective observational studies [7, 8, [10] [11] [12] [13] [14] [15] [16] , three retrospective studies [9, 17, 18] , and one study where insufficient details were available to determine the type of the study [6] . CMV IgG was positive in all the subjects in four studies [10, 11, 14, 16] , not measured in four studies [12, 15, 17, 18] , and positive in 28 to 94% of the subjects in five studies [6] [7] [8] [9] 13] . Other inclusion criteria were sepsis in four studies [6, 7, 16, 17] , mediastinitis in one study [13] , simplified acute physiology score (SAPS) II of 41 or higher in one study [10] , prolonged ICU stay in three studies [8, 9, 16] , fever for more than 72 hours in one study [18] , and shock or organ failure in two studies [12, 16] . There were five studies in which corticosteroid use was documented [8, 12, [16] [17] [18] . In one study, eight of 48 patients were recipients of long-term corticosteroid therapy or had a malignancy [12] . In a case-control study, 22 of 40 of the cases and 13 of 40 of the controls were recipients of short-term corticosteroids ( 3 months) [18] . The details of corticosteroid use were unavailable in three studies [8, 16, 17] . 