The Adult Dengue Platelet Study (ADEPT) by the National University Hospital (NUS), Singapore General Hospital (SGH), Changi General Hospital and Malaysia’s University Malaya Medical Centre (UMMC) has made local headlines again, just three weeks after the study’s findings were published in the Lancet.

According to findings, platelet transfusions are not necessary in treatment of dengue patients with critically low platelet counts – a conclusion that can change the way dengue patients are treated and cut the rates of unnecessary transfusions, inadvertently freeing up limited blood platelet stocks for patients who are really in need of transfusion.

"With this study, the evidence is very strong," said Associate Professor David Lye, a senior consultant at Tan Tock Seng Hospital's Institute of Infectious Diseases and Epidemiology.

"It's quite clear - unless you have serious bleeding, you don't need a transfusion."

Supportive care more important for dengue patients

The platelet count of a health individual ranges between 150,000 and 250,000 per microlitre of blood. However, up to 90% of patients with dengue infection will have platelet levels below 100,000, while 10% to 20% of patients will have dangerously low levels that fall below 20,000, in which case most will receive prophylactic platelet transfusions.

However, findings from the study reveal that most patients with severely low platelet counts will recover without any intervention after a few days.

"The issue here is when the platelet count drops to a critically low level, most clinicians will feel unsafe not to do something,” said director of the Institute of Infectious Diseases and Epidemiology at Tan Tock Seng Hospital, Professor Leo Yee Sin.

“In other words, most clinicians will go ahead to transfuse platelets to this group of uncomplicated patients and this study shows that it is not necessary to do so,” she also said.

Platelet transfusion widely used in treatment of dengue

According to Leo, the World Health Organisation (WHO) has long issued recommendations against transfusions since 2009, however, the team explained that they conducted the study as they observed that “prophylactic platelet transfusion is widely used despite the dearth of robust evidence.”

While the 2015 Clinical Practice Guidelines for Management of Dengue Infection in Adults by the Malaysian Ministry of Health (MOH), states that routine prophylactic transfusion with platelets and fresh frozen plasma has no role in the management of dengue infection, SGH has revealed that there is a wide range of practices as there were no standard protocols on transfusion in dengue patients without signs of active bleeding.

Each bag of pooled platelets transfused to a dengue patient requires contribution from four individual donors. It is hoped that the new findings will ease the pressure on Singapore’s national blood bank.

"We have already changed our practice since the study began, and do not give prophylactic platelet transfusions," said Associate Professor Sophia Archuleta, a senior consultant at the NUH infectious diseases division, adding that platelets are only transfused if there is serious bleeding.

NUS researchers paved new pathways for treating dengue

Dengue fever is a serious global health concern, having infected over 13,000 individuals in Singapore in 2016. In the same year, the Malaysian Health Ministry reported a total of 101,357 cases of dengue fever.

Though the dengue vaccine has been made available in some countries, there are no other known alternative therapies. However, team of nine researchers from the NUS, led by Associate Professor Ganesh S Anand of the Department of Biological Sciences, has discovered hidden vulnerabilities on the dengue virus surface, which can be targeted to treat the disease.

"When the dengue virus is outside the human host, several of its surface regions are tucked away within a compact soccer ball-like arrangement. When the virus enters a human host, it senses an increase in temperature and puffs up to reveal new surfaces,” said Ganesh.

“This is a very exciting discovery as it offers numerous possibilities of designing therapies and vaccines to target these exposed surfaces to treat dengue as well as other related viruses such as Zika and chikungunya. Our team will be working towards this goal." MIMS

Read more:
Local study finds no benefit for routine platelet transfusion in dengue patients
First dengue vaccine commercially available this week in Singapore
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