BANGKOK (Thomson Reuters Foundation) - Health experts called on Thursday for urgent action to tackle the "global dengue pandemic", and said the number of cases was expected to spike in some countries this year, partly because of the El Niño weather phenomenon.

The experts, from several organizations, urged governments in the region to support collaborative efforts to combat the spread of dengue in Asia, which had the highest incidence of the disease in the world.

One impetus for the call to action is Sanofi Pasteur's new Dengvaxia vaccine that has received approval in Mexico, Brazil, El Salvador and the Philippines, said Dr. In-Kyu Yoon, director of the Dengue Vaccine Initiative (DVI), adding that other vaccines were in the development pipeline.

With dengue experts on its staff and board, DVI - one of the groups behind the call - is part of the Seoul-based International Vaccine Institute and has received support from Sanofi Pasteur to raise awareness about dengue vaccination.

"The dengue problem won't just go away and won't be helped by half measures. If countries and regions want to tackle the issue effectively, it will take a huge commitment on the part of individual countries and regions, groups of countries, to address it," Yoon said.

Experts have said Dengvaxia is not perfect and does not protect equally against the four different serotypes of dengue, but is a tool that can be part of an integrated approach for prevention of the disease.

Other drugmakers including Japan's Takeda and U.S. Merck are also working on dengue vaccines but are several years behind.

VACCINE PART OF INTEGRATED APPROACH

Sanofi Pasteur said last year studies it had carried out had shown the vaccine protected two-thirds of the participants.

Protection against severe dengue reached 93 percent, while prevention of hospitalization due to the disease reached 80 percent in the volunteers, who were aged nine and above, it said in a statement.

"There's a lot of thought that perhaps if we have a vaccine, that we'll be able to ease off on doing other parts of the overall effort, for example, vector control, surveillance, some of these other things," Yoon said by telephone from Colombo, where he was attending a dengue conference.

"The fact is, really it will require all aspects. That is part of the call to action - it needs to be an integrated approach. There is no magic bullet... it is a tool that can be in a country's toolbox."

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Dengue - which causes flu-like symptoms and can develop into the deadly dengue hemorrhagic fever - is the world's fastest-spreading tropical disease, with the annual number of cases increasing 30-fold in the last 50 years, according to the World Health Organization (WHO).

The disease is endemic in 128 countries - compared with nine countries experiencing severe dengue epidemics prior to 1970. Asia has the most cases, with 67 million people infected per year, researchers say.

The experts called on countries, if they register the vaccine for use, to develop and implement vaccine programs that are monitored and evaluated for safety.

They also urged governments to "accelerate effective dengue prevention and control interventions".

There is no dedicated treatment for dengue, also known as breakbone fever, and patients are generally asked to rest, drink plenty of fluids and take medication to bring down fever and reduce joint pains.