Last month, Mexico approved the use of Sanofi Pasteur’s dengue vaccine, Dengvaxia®, which is the first available dengue vaccine against all four strains of dengue virus (DEN-1, DEN-2, DEN-3, and DEN-4).
Yesterday, the Health Sciences Authority (HSA) of Singapore approved the dengue vaccine Dengvaxia® for the prevention of dengue infection in individuals aged 12 to 45 years. It will be commercially available in a few months time and the vaccination regime will require three doses to be administered over 12 months. Each dose will be given at the 0, 6th and 12th month.
Two groups of experts from HSA’s Medicines Advisory Committee and Dengue Expert Panel, comprising medical doctors and infectious diseases specialists, were consulted during the review to ensure that the vaccine is relevant and the benefits outweigh the risks for the Singapore population.
HSA’s regulatory approval is based on a review of the 24 clinical studies conducted by Sanofi in over 41,000 subjects.
Overall, the vaccine was effective in reducing dengue illness by 60%, and reducing severe dengue illness by 84%. Efficacy differed by serotypes, age groups and prior dengue exposure in the patient. Vaccine efficacy is defined as the percentage reduction of dengue disease in a vaccinated group of people compared to an unvaccinated group.
The vaccine was less effective against DENV-1 and DENV-2, which are the predominant strains in Singapore. The vaccine efficacy was 50% for DENV-1 and 40% for DENV-2 versus 75% for DENV-3 and 77% for DENV-4 infection.
It was also seen that the vaccine provided significantly better protection to those who have had a prior exposure to dengue (81% protection), as compared to those without previous dengue infection (38% protection). The vaccine is less likely to benefit those who did not previously have dengue.
As the vaccine is more effective in those who had previous dengue infection, and that there is a postulated risk of severe dengue in those who do not have past dengue infections when they become infected subsequently, it is recommended that individuals interested in getting the vaccine consult their doctors on the benefits and risks of the vaccination.
Doctors may consider a blood test, when available, to determine their past infection status. This may provide additional information to enable the individual to make an informed decision on the benefits versus risks of vaccination.
Though this vaccine is currently approved only from age 12-45 years, HSA says it is prepared to review the approved age range once more clinical data becomes available, that reduces the concern on those under 12 years old, and that provides more data on those above 45 years old.
Dengue, the mosquito-borne disease is endemic in Singapore with over 12,054 dengue cases reported here as of October 3 which is higher than the entire count of 11,286 cases reported last year.
Dengvaxia® has also been approved in countries including Brazil, Philippines, El Salvador, Costa Rica, Guatemala, Peru, Indonesia and Paraguay.