Abstract Background There have been no studies reporting functional, cognitive, inflammatory or endothelial outcomes after dengue shock (DS), or septic shock (SS) in Vietnam. Methods We conducted a prospective observational study to follow-up adult survivors of DS and SS. At hospital discharge, 1-, 3-, and 6-month follow-up, we measured health-related quality of life (EQ-5D-5L), cognitive function (Montreal Cognitive Assessment, MoCA), endothelial function (EndoPAT), and plasma biomarkers of inflammation (ferritin, IL-6, CRP) and endothelial activation (Ang1, Ang2, VCAM-1). Results Participants included survivors of DS (n = 130), SS (n = 26), and healthy controls (n = 25). Survivors of DS had median EQ-5D-5L visual analogue score (VAS) > 90/100 at all time-points, and mildly impaired MoCA scores at hospital discharge, which had normalized by 3 months (normal ≥ 26, median [25th;75th centile] 23/30 [20;26] at discharge, 27/30 [25;29] by 3 months). Survivors of SS had lower median EQ-5D-5L VAS at all time-points (median [25th;75th centile] 80/100 [70;95] at discharge, and 90/100 [80;95] by 6 months), but MoCA scores never returned above the normal threshold (median 17/30 [13;19] at discharge, 20/30 [17;21] at 6 months). We found higher IL-6 and ferritin at all post-discharge time points in both DS and SS groups versus healthy controls (P < .01 for all comparisons). After 6 months, 38% with DS and 62% with SS still had ferritin levels >95th percentile of the healthy control distribution. There was little evidence of simultaneous endothelial activation. Conclusions This is the first report of persistent subclinical inflammation after DS, and SS in Vietnam; further research is required to determine the duration and clinical significance of this phenomenon.