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.