The mortality rate for severe dengue infection is 0.8% to 2.5%.[1]World Health Organization, Regional Office for South-East Asia. Comprehensive guidelines for prevention and control of dengue and dengue haemorrhagic fever - revised and expanded edition. 2011 [internet publication].
https://apps.who.int/iris/handle/10665/204894
Children are at an increased risk of severe infection and death compared with adults; however, severe infection in adults is increasingly being reported.[1]World Health Organization, Regional Office for South-East Asia. Comprehensive guidelines for prevention and control of dengue and dengue haemorrhagic fever - revised and expanded edition. 2011 [internet publication].
https://apps.who.int/iris/handle/10665/204894
[14]Guzman MG, Kouri G. Dengue and dengue haemorrhagic fever in America: lessons and challenges. J Clin Virol. 2003 May;27(1):1-13.
http://www.ncbi.nlm.nih.gov/pubmed/12727523?tool=bestpractice.com
[15]Teixeira MG, Barreto M. Diagnosis and management of dengue: clinical review. BMJ. 2009 Nov 18;339:b4338.
http://www.ncbi.nlm.nih.gov/pubmed/19923152?tool=bestpractice.com
[39]Halstead SB. Dengue. Lancet. 2007 Nov 10;370(9599):1644-52.
http://www.ncbi.nlm.nih.gov/pubmed/17993365?tool=bestpractice.com
The risk of a child ages 1 to 5 years dying from dengue infection is fourfold higher compared to children ages 11 to 15 years.[40]Gamble J, Bethell D, Day NP, et al. Age-related changes in microvascular permeability: a significant factor in the susceptibility of children to shock? Clin Sci [Lond]. 2000 Feb;98(2):211-6.
http://www.ncbi.nlm.nih.gov/pubmed/10657278?tool=bestpractice.com
Even though dengue hemorrhagic fever (DHF) and dengue shock syndrome are uncommon in adults, a higher morbidity and mortality rate has been reported, especially in older people, which is related to an increased risk of organ impairment.[1]World Health Organization, Regional Office for South-East Asia. Comprehensive guidelines for prevention and control of dengue and dengue haemorrhagic fever - revised and expanded edition. 2011 [internet publication].
https://apps.who.int/iris/handle/10665/204894
[15]Teixeira MG, Barreto M. Diagnosis and management of dengue: clinical review. BMJ. 2009 Nov 18;339:b4338.
http://www.ncbi.nlm.nih.gov/pubmed/19923152?tool=bestpractice.com
[41]Kularatne SA, Patirage MM, Pathirage PV, et al. Cardiac complication of a dengue fever outbreak of Sri Lanka, 2005. Trans R Soc Trop Med Hyg. 2007 Aug;101(8):804-8.
http://www.ncbi.nlm.nih.gov/pubmed/17428513?tool=bestpractice.com
[42]Kularatne SA, Pathirage MM, Gunasena S. A case series of dengue fever with altered consciousness and electroencephalogram changes in Sri Lanka. Trans R Soc Trop Med Hyg. 2008 Oct;102(10):1053-4.
http://www.ncbi.nlm.nih.gov/pubmed/18617208?tool=bestpractice.com
[43]Gulati S, Maheshwari A. Atypical manifestations of dengue. Trop Med Int Health. 2007 Sep;12(9):1087-95.
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3156.2007.01891.x/full
http://www.ncbi.nlm.nih.gov/pubmed/17875019?tool=bestpractice.com
According to one meta-analysis, a positive tourniquet test, ascites, and shock were identified as the best predictors of dengue infection, DHF, and mortality, respectively.[17]Guo C, Zhou Z, Wen Z, et al. Global epidemiology of dengue outbreaks in 1990-2015: a systematic review and meta-analysis. Front Cell Infect Microbiol. 2017 Jul 12;7:317.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5506197
http://www.ncbi.nlm.nih.gov/pubmed/28748176?tool=bestpractice.com
Long-term sequelae
There are no long-term sequelae associated with dengue infection once the patient has recovered; however, some patients may experience post-viral fatigue syndrome after recovery. The patient's platelet count gradually increases during convalescence; however, some patients may develop temporary thrombocytosis during recovery. Complete normalization of liver function tests may take up to 3 or 4 weeks.
Recurrence
Recurrence is possible with a different dengue virus serotype, leading to secondary dengue infection. Third and fourth recurrences of clinical infection can also occur, but the clinical impact is not very clear. Once immunity has developed to all 4 serotypes, lifelong immunity to each serotype occurs.