Epidemiology

Global incidence has markedly increased over the past two decades, with a 10-fold surge in reported cases from 500,000 cases in 2000 to 5.2 million cases in 2019 (in 129 countries and territories). There was a slight decline in cases between the years 2020 and 2022 due to the coronavirus disease 2019 (COVID-19) pandemic and a lower reporting rate, but an upsurge in global cases was observed in 2023. Since the beginning of 2023, over 5 million cases and over 5000 deaths have been reported in over 80 countries and territories. Approximately 80% of these cases were reported in the Region of the Americas. Escalated outbreaks have been reported in severe countries, including Bangladesh, Brazil, Burkina Faso, Fiji, the Philippines, and Vietnam.[5]

​Approximately half of the world’s population are at risk of dengue infection. It has been estimated that 100-400 million infections occur per year, although most cases are mild or asymptomatic. The virus is endemic in more than 100 countries, including countries in the Southeast Asian and Western Pacific regions, the Americas, Africa, and the Eastern Mediterranean. Asia represents approximately 70% of the global burden of disease. Dengue is spreading to new areas in Europe, South America, and the Eastern Mediterranean.[6][7]​​​ With the expansion of Aedes mosquito populations globally, the potential for dengue outbreaks, especially in non-endemic regions with dengue-susceptible populations, is high.[8]

While dengue is not endemic in the US, there have been multiple epidemics of dengue fever in the US in the 18th to early 20th centuries. After an absence of 56 years, dengue fever has re-emerged in US states, with local transmission reported in Florida, Hawaii, Texas, and Arizona.[9][10]​ Between 2010 and 2020, approximately 30,000 cases were reported, with children and adolescents disproportionately affected.[11] In 2023, 1206 locally-acquired cases and 1712 travel-associated cases were reported in the US.[12]

​Dengue fever is not endemic in the UK. All cases reported have been acquired as a result of travelling to endemic areas. In 2022, 382 travel-associated cases were reported in England, Wales, and Northern Ireland, with most cases originating from Southern Asia.[13]

Approximately 90% of cases of dengue haemorrhagic fever (DHF) are in children under 5 years of age.[1] Classical dengue fever (DF) is more common in adults compared with children.[14] Severe manifestations such as DHF and dengue shock syndrome (DSS), as well as other unusual manifestations, are increasingly being reported in previously unaffected regions.[15][16]​DHF has been reported in many tropical US territories, including Florida, and the DENV-2 virus has been implicated in some of these cases.​[17]

The pooled mean age of infected patients is 30.1 years (54.5% male).[18]

HealthMap: interactive map of global dengue activity Opens in new window

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