Although the dengue virus was identified in the early 20th century, and the disease itself known since at least the time of the Jin Dynasty in China (265-420 AD), there is still no direct treatment for dengue fever.
What doctors currently prescribe for patients is supportive treatment to help manage symptoms and prevent potential complications.
There are a number of reasons why it is so challenging to come up with a dengue treatment.
According to Drugs for Neglected Diseases initiative (DNDi) Dengue Global Programme head Dr Andre Siqueira, one challenge is the length of time the dengue virus is actually in the body.
“The dengue virus stays in the body for around 10 days, but usually after the onset of fever, it’s about four to five days on average.
“So that means that we need to start treatment very early to have an effect,” he explains.
As people tend to only realise they are ill when the fever starts, this means that the potential period of treatment with a drug that targets the virus is already halved.
To further complicate matters, some people might not go to see the doctor straight away, preferring to wait and see if the fever will resolve itself.
In addition, doctors might not suspect dengue fever immediately, especially if the other symptoms are vague, as fever is a common symptom across many diseases.
The other reason developing a drug for dengue is difficult is because part of the illness is actually caused not by the virus, but by the body fighting the virus.
“Some of the complications are directly caused by the virus, and others are caused by the immune response – the inflammatory response that the body directs to the virus and ends up being damaging to the body,” says Dr Siqueira.
“So, when someone has the severe symptoms, usually, the virus is not there any more.
“But there was an inflammatory storm that caused all the changes that end up in complications, such as plasma leakage that causes shock.
“So, the person gets circulatory shock, which can be a very damaging complication and eventually even cause death.”
There are also more practical reasons for why a treatment for dengue has not been forthcoming, i.e. lack of resources and investment.
Despite affecting a significant part of the world, dengue has been seen as a disease of tropical nations, which are usually low or middle-income countries that may lack the resources to pursue such scientific research.
However, Dr Siqueira points out that climate change is now changing the areas where the virus’ main mosquito host – Aedes aegypti – can live, so more countries could potentially be affected by this disease.
He adds: “It’s a more connect- ed world; that also means people get higher risk of being infected.”
Two potential drugs
The need for a dengue treatment led to the formation of the Dengue Alliance in 2022.
This partnership between DNDi and institutions from four dengue-endemic countries – Brazil, India, Malaysia and Thailand – focuses on pre-clinical research, repurposing current drugs to treat dengue, and clinical trials for potential dengue medications.
Dr Siqueira shares that: “Because of these difficulties [mentioned above], one of the approaches that we are taking is to target both the development of antivirals and what we call host-directed therapies, which are therapies that are targeted at the inflammatory response of people that can reduce this inflammatory storm and reduce the associated complications.
“So, we are actually going for these two streams, and eventually, even a combination of these drugs that could be more effective.”
He is confident that having a good treatment for dengue will have a huge impact.
“The main purpose is reducing complications, reducing deaths, but we are thinking also to reduce the duration of symptoms, the amount of time a person is unable to do their activities, such as work or study, which causes a lot of other socioeconomic consequences for the individuals.”
He shares that the Alliance is looking to begin testing two promising drug candidates by next year.
One candidate is a monoclonal antibody already in phase III clinical trials in India, where it was developed by the Serum Institute of India.
Following a memorandum of understanding (MOU) between DNDi and the Serum Institute, this monoclonal antibody will be made available to Dengue Alliance members to carry out phase III clinical trials in their own countries.
In Malaysia, the Dengue Alliance partner is the Health Ministry.
Health deputy director-general (Health and Technical Support) Datuk Dr Nor Fariza Ngah is excited about this development as it could potentially be the first treatment for dengue in the world.
She shares: “We have identified a few sites (for the clinical trials).
“The main one is Hospital Raja Permaisuri Bainun (in Ipoh) where our main primary investigator is Dr Steven Lim, a consultant infectious diseases physician.
“We also have a few cluster hospitals, as well as the KK [Klinik Kesihatan or Health Clinic] surrounding them.
“But at the same time, we will also consider any hotspots that pop up.”
As the monoclonal antibody needs to be administered intravenously (IV), patients will need to go to the hospital for the treatment, but the Health Clinics will be involved in referring them to the relevant hospitals.
The treatment is expected to take about an hour to be administered and to be open to dengue patients from age five onwards.
Meanwhile, Dr Siqueira shares that the other drug candidate will be an oral pill, but that DNDi is still negotiating with the manufacturers for the best one to take to a phase III clinical trial.
“We have two potential candidates, we’re still trying to choose which one would be the best to move forward with,” he says.
While an effective dengue treatment is the main goal, Dr Nor Fariza notes that: “But, of course, under the Dengue Alliance, as well as DNDi, our intention is to have an affordable treatment, easy access and one that is user-friendly as well.”
Prevention first
She also points out that we have various tools and methods available to help prevent the spread of dengue.
“Malaysians also have to care for themselves,” she says.
“First is prevention, which means you should ensure there are no dengue mosquitoes around, i.e. no possible breeding sites.”
As these mosquitoes can breed in very small spots of clear water, we need to ensure our surroundings are clean and clear of such sites.
This is especially so in the current hot weather as viruses can replicate fast in such temperatures, she says.
Dr Nor Fariza also advises the public to be aware of areas that are dengue hotspots and take the proper precautions.
“Don’t take for granted any fever, especially if you are in a hotspot.
“Go see the doctor and get a dengue test done.
“And if the doctor advises for hospital admission, please admit yourself – we won’t ask you to admit without reason!”
She explains that doctors usually advise dengue patients to be admitted to the hospital when they have symptoms or risk factors that indicate they are prone to developing serious complications like dengue haemorrhagic fever.
There are also currently two vaccines being used to prevent dengue.
One, known as TAK-003, is available in the private sector for Malaysians.
Dr Nor Fariza shares that according to post-market surveillance data provided by the manufacturer, 28,693 vaccine doses have been administered as of Feb 9 (2026) since its official launch in 2024.
The price, however, remains a factor as it costs around RM300-500 for the two doses needed.
The other vaccine, developed and approved in Brazil, has been temporarily suspended in the South American country as health authorities there investigate two deaths that have been linked to the single-dose vaccine.
