What is Dengue?

Dengue fever is a disease caused by the dengue virus, which is transmitted by female mosquitoes mainly of the species Aedes aegypti. There are four serotypes of the virus that cause dengue — DENV-1, DENV-2, DENV-3 and DENV-4. Hence, individuals can be infected with dengue up to four times.

First time dengue infection is believed to provide lifelong immunity against that serotype. However, subsequent dengue infections by other serotypes may carry high risk of developing severe dengue,
dengue haemorrhagic fever or dengue shock syndrome, which can be life-threatening.

Symptoms of Severe Dengue

Severe dengue, dengue haemorrhagic fever and dengue shock syndrome are dengue infections that become severe and potentially have fatal complications, which often require hospitalization. Symptoms of severe dengue generally develop after the fever has gone down, followed by:

Severe bleeding such as gum bleeding, nose bleeding, bleeding into the skin and organs
Abdominal pain
Persistent vomiting
Rapid breathing
Fatigue
Restlessness
Blood in vomit
Death

If you think you have dengue, consult your doctor and seek medical attention immediately.

Dengue Cases in Singapore

Singapore saw one of its worst dengue outbreaks in 2020, recording 35,315 cases and 28 deaths. As of 28 May 2022, about 11,670 dengue cases had been reported in Singapore, with 10% of cases requiring hospitalisation.

National Environment Agency (NEA) urges all individuals to break disease transmission by removing stagnant water and potential mosquito breeding sites.

The Dengue Vaccine

There is no specific treatment for dengue fever, severe dengue, dengue haemorrhagic fever and dengue shock syndrome. Fortunately, there are supportive therapies in Singapore and also dengue vaccine, Dengvaxia®, available for the prevention of subsequent dengue infections. Dengvaxia® dengue vaccine has been approved by Health Sciences Authority (HSA).

Who is suitable for Dengvaxia® dengue vaccine?

For individuals above 12 years of age, with previous dengue infection
For individuals not previously infected by dengue virus, vaccination is not recommended as an increased risk of hospitalization for dengue and severe dengue has been observed

How do I check for a previous dengue infection?

Serologic test is mandatory for all individuals before getting a vaccine
Serologic test is a blood test to identify previous dengue infection or individuals with an unknown history of previous dengue infection

How is the vaccine given?

The vaccine will be injected underneath the skin in the upper arm
The vaccination includes 3 injections of 0.5ml each over a period of 12 months, with a 6-month interval at month 0, 6 and 12
3 injections are needed to obtain the optimal benefit of the vaccine so it is important not to miss any dose

What are the precautions to note?

Do not use Dengvaxia® if you:
- Do not have a prior dengue infection,
- Are allergic to the active substances or prior administration of any vaccines,
- Have a weakened immune system,
- Are suffering from a disease with mild to high fever or acute disease,
- Are pregnant,
- Are breastfeeding.

Is Dengvaxia® Effective?

HSA’s regulatory approval is based on a review of the 24 clinical studies conducted by Sanofi in over 41,000 subjects. The evaluation are:

Dengvaxia® has an efficacy of 60% in reducing dengue illness, and 84% in reducing severe dengue illness.
It is especially effective in protecting against DENV-3 and DENV-4, showing an efficacy of 75% and 77% respectively.
It has been shown in providing significantly better protection to those who had prior exposure to dengue with an efficacy of 81%.
Results have shown that it is effective up to four years from the administration of the last dose.

Source: https://www.hsa.gov.sg/announcements/news/hsa-approves-dengvaxia-vaccine

If you have any questions on the Dengvaxia® dengue vaccine, you may make an appointment to consult our doctors at Thomson Wellth Clinic.