Due to that, Minister Dr S Subramaniam said he was hesitant about introducing the vaccine in Malaysia.

He said the dengue mosquito had four strains, of which the first infection was usually milder while exposure to the virus for the second time was often severe and sometimes fatal.

“This is why developing an effective vaccine is a challenge. An inadequate vaccine could make people sicker.

“Recent studies in the US showed that giving the vaccine to people who have not been exposed to the dengue virus before could be dangerous,” he said at a press conference after launching the 11th Allied Health Scientific Conference Malaysia 2016.

Subramaniam said this when asked if vaccination against dengue would be allowed in Malaysia. He replied that his ministry would be the first to register and use the vaccine if it had met all the requirements.

The study in the US also observed that the vaccine reduced illness and hospitalisation of patients by 20 to 30 per cent in areas exhibiting a high incidence of infection.

However the vaccine increased the rate of illness and hospitalisation in areas where the incidence of infection was relatively low.

He explained to avoid such a scenario, a blood test from people living in the infected areas was needed to determine antibody levels against the different strains of dengue.

“After knowing the level of antibodies within people from infected areas, the vaccine could be given.

“That process is very tedious and expensive to do at the community level. It is virtually impossible.”

During the first eight months of this year, 71,590 dengue cases and 162 deaths were reported nationwide.