Risk of long-term health complications after dengue recovery

People who caught dengue and recovered are more likely to face long-term health complications about a year later compared to those who contracted COVID-19, according to a nationwide study led by Nanyang Technological University, Singapore (NTU Singapore) and published in the Journal of Travel Medicine.

Based on tests and medical claim records of 11,707 residents in Singapore with dengue and 1,248,326 who had COVID-19 (Delta and Omicron variant) between July 2021 and October 2022, the study looked for newly arising health problems related to the heart, neurological and immune system that appeared 31 to 300 days after the infection. The study is the first to examine the long-term risk of multiple health complications following dengue and the first to contrast the post-recovery risk of dengue and COVID-19 patients.

“We were motivated to conduct the study due to the increasing geographic range of dengue due to climate change,” said lead author Assistant Professor Lim Jue Tao, from NTU’s Lee Kong Chian School of Medicine (LKCMedicine). “Dengue is one of the most common vector-borne diseases globally, and long-term health issues resulting from dengue can substantially increase the healthcare burdens of the infected person and the country.

“We also decided to compare the results against those who recovered from COVID-19 as our previous work had suggested increased risk of similar long-term health complications.”

The researchers’ statistical analysis of their data revealed that people who had dengue were at higher risk of developing long-term health complications compared to those who had COVID-19 — with 55% increased long-term risk of any heart complications (including irregular heartbeats, heart disease and blood clots), 213% increased risk of cognition or memory disorders and 198% increased risk of movement disorders in dengue patients compared to COVID-19 patients.

The researchers noted that there are limitations to the study. They only tracked adults aged 18 years and older, which means their findings cannot be generalised to the paediatric populations. Individual susceptibility to COVID-19 and dengue through genetic, behavioural or environmental factors, which can influence risk estimates, was also not considered.

The study has nevertheless been described as “crucial” by independent expert Professor Kwok Kin-on, from The Chinese University of Hong Kong, who said it “provides the first comprehensive comparison of post-recovery health issues between dengue and COVID-19 patients, offering valuable insights for healthcare planning and patient management”.

“Additionally,” he said, “the findings underscore the need for increased vigilance and targeted interventions for those recovering from dengue to mitigate long-term health impacts.”

In the future, the researchers will compare the risk of long-term health complications across different dengue serotypes (variants) and the economic costs incurred from these complications.

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