Severe symptoms occur in up to 5 per cent of cases. Hospitalisation keeps case fatality at below 2.5 per cent, and improving case management has led to a 28 per cent decline in case fatality between 2010 and 2016.16,17

While the main risk factors for severe dengue include young age and chronic diseases, severe dengue is also more likely in someone who has already been infected with dengue previously. Risk is especially increased due to secondary infection, with two sequential infections by different serotypes.19,20

Severe dengue fever symptoms prompting an emergency referral include a swollen or painful abdomen, persistent vomiting, vomiting blood, bleeding gums, respiratory problems, a racing but weak pulse, clammy skin, and drowsiness or loss of consciousness. Further complications include dengue haemorrhagic fever and/or dengue shock syndrome (DHF/DSS).