Dengue vaccine approved for use in S'pore
THE world's first dengue vaccine has been given the green light by the Health Sciences Authority (HSA), and will be available in Singapore in a few months.
It is most effective in people who have had dengue before and - underscoring the difficulty in vaccinating against a virus that has four distinct strains - is also less effective against the two that are more common here.
But experts say it still holds promise against the mosquito-borne virus which, at the end of September, had infected 11,874 people this year, surpassing the number for the whole of last year.
The Health Sciences Authority (HSA), studying the vaccine since March, fast-tracked its approval process because of the public health concerns.
The decision to approve Dengvaxia was based on 24 studies conducted by vaccine manufacturer Sanofi Pasteur, which involved more than 41,000 people and showed the vaccine to be safe for use and effective against dengue.
Given in three doses over the course of a year, it is approved for use in those aged between 12 and 45 years. Those who fall outside this age group but wish to be vaccinated can still do so, but should seek a doctor's advice.
Before it becomes available, the HSA will be embarking on efforts to educate doctors and the general public on the benefits and limitations of the vaccine.
In people aged two to 16, Dengvaxia was shown to reduce the number of dengue cases by 60 per cent compared with those who were not vaccinated. This figure went up to 84 per cent when it came to preventing severe dengue infections in the same age group.
Additional studies showed that the vaccine was effective up to age 45, said the HSA yesterday.
While it is formulated against all four strains, the vaccine is less effective at protecting against the Den-1 and Den-2 strains, which account for three-quarters of the dengue cases in Singapore.
Against these, its efficacy is 50 per cent and 40 per cent respectively, compared with 75 per cent and 77 per cent for the other two strains.
Studies also showed the vaccine provided better protection for those who had been exposed to the dengue virus than for those who had not, with efficacy at 81 per cent and 38 per cent respectively.
How much Dengvaxia reduces dengue infections would depend ultimately on how many people choose to be vaccinated, said Professor Ooi Eng Eong, deputy director of the emerging infectious diseases programme at Duke-NUS Medical School.
"The larger this number, the greater the impact vaccination would have on reducing the number of dengue cases in Singapore," added Prof Ooi, also a scientific advisory board member on dengue for Sanofi.
Said Professor Tikki Pang, a visiting professor at the Lee Kuan Yew School of Public Policy: "If you can prevent a certain number of cases, that, to me, is already worth it."