Dengue fever is an acute febrile illness that can be caused by virus serotypes 1, 2, 3 and 4.  According to the Centers for Disease Control and Prevention, dengue infects 400 million people worldwide each year. Just in Singapore, 12,616 cases of dengue fever have been reported between January to October 2019 – this number exceeds by far the number of such cases in the same period last year. There is a severe form of this infection, called dengue hemorrhagic fever, which can be fatal without medical attention. In just the first 7 months of 2019, 9 deaths have been recorded from dengue in Singapore. The

Neighbouring countries such as the Philippines have also been facing epidemics, with a staggering 146,602 cases of dengue fever and 622 deaths from the disease being recorded in the country in just the first 7 months of 2019. The number of cases reported is 98% more than those reported in the same period in2018  and this can be largely attributed to the ban of the controversial dengue vaccine, Dengvaxia.

The Dengue Vaccine

Introduced by pharmaceutical giant Sanofi Pasteur in Mexico in December 2015, Dengvaxia is the first vaccine to protect against dengue fever – specifically, serotypes 1, 2, 3 and 4 of the disease. According to the World Health Organisation (WHO), “a safe, effective and affordable dengue vaccine against the four strains would represent a major advance for the control of the disease” and “could be an important tool for reaching the WHO goal of reducing dengue morbidity by at least 25% and mortality by at least 50% by 2020.”

However, amidst the death of at least 14 children in the Philippines after immunisation with the dengue vaccine, concerns began to surface about its safety. Dengue fever was named as the source of death of these 14 children who had previously received the vaccine. Since then, the WHO as well as Sanofi, the manufacturer of the vaccine, have invested in intensive research and testing and determined that the dengue vaccine, Dengvaxia, is only suitable for use in people who have previously been infected with dengue.

Sanofi discovered that “individuals who have never had a dengue infection before pose a significantly higher risk of a more severe form of the disease and hospitalisations with Dengvaxia than if they had not been vaccinated against dengue at all.”

Who should receive the vaccine

Those between the ages of 12 and 45 years may receive the vaccine if they are able to provide records of having been infected by dengue previously OR through serological testing (Dengue IgG). This advisory followed an indication by Sanofi that severe illness could be caused in children who have not previously been infected by dengue if they are administered Dengvaxia. The Health Science Authority (HSA) of Singapore has issued a similar advisory.

For those who have previously been infected with dengue, however, the vaccine can prove to be extremely useful – an efficacy of up to 81% in preventing repeat infection has been estimated. Moreover, those who have developed a certain serotype of dengue in the past and are at risk of developing other serotypes of the dengue infection, have a higher risk of complications and mortality if they do get infected again, but with other serotypes. It is advisable that they therefore, get vaccinated with Dengvaxia.

Dengvaxia has also been shown to be especially effective in protecting against serotypes 3 and 4 of dengue. Those who have previously been infected with serotypes 1 and 2 would have more incentive to get vaccinated so that they will not have to face severe complications in case they are infected again with either serotypes 3 or 4 of dengue.

How to protect yourself against dengue if you have not been infected before

In the battle against dengue fever, it is important to stay alert and remain in the know about dengue “hotspots” or clusters in Singapore and other countries. These hotspots are regions where there has been a documented outbreak of dengue and where a significant number of people have been infected. Local dengue clusters include areas such as Choa Chu Kang, Jurong West and Toa Payoh – updated information on the latest dengue hotspots can be found on the National Environment Agency’s (NEA) website. It would be prudent to periodically check the website to check if your neighbourhood or neighbourhoods nearby have been affected by the outbreaks.

The NEA has taken action such as surveillance of homes and stop-work orders to protect residents as well as construction workers from the danger of contracting dengue. Moreover, neighbouring countries such as the Philippines have also been facing epidemics, with a staggering 146,602 cases of dengue fever and 622 deaths from the disease being recorded in just the first 7 months of 2019. The number of cases reported is 98% more than those reported in the same period in the year before and this can be largely attributed to the ban of the controversial dengue vaccine, Dengvaxia.

As advised by the Ministry of Health (MOH), the most effective methods of preventing dengue, whether locally or during travel, is through the liberal application of insect repellent, wearing long covered clothing, sleeping in air-conditioned rooms or rooms with wire mesh screens, sleeping under mosquito nets and frequently checking for and removing stagnant water in your environment.

About the Dengue Vaccine

• • When to get vaccinated: If you have been infected with dengue previously, upon full recovery from the disease and after consulting a physician, it is advisable that you receive the dengue vaccine as soon as possible if you think that you are once again at risk of developing the disease
  • Where to get the vaccine: The dengue vaccine is not commonly available due to the advisory put out by the HSA as well as the WHO. Our clinic offers it only to those who either have proper records to show that they have previously been infected with dengue OR to those who can undergo serological testing to produce proof of past infection.
  • How long it lasts: The dengue vaccine is effective for up to 4 years, after which you may need a booster (only applicable to those who have previously been infected)
  • Vaccine dosage: For those who have previously been infected with dengue, one dose every 4 years is recommended. 
  • What are the possible side effects of receiving the vaccine:
    • • reactions such as swelling, pain and redness at the injection site
    • • headache
    • • malaise
    • • fever
    • • muscle pain
    • Do note that those who have not previosuly been infected with dengue are recommended NOT to receive the dengue vaccine because they are at risk of developing a severe form of dengue fever upon receiving the vaccine, which can lead to serious complications and even death.
• Who should get the vaccine? Those between the ages of 12 and 45 who can either provide records of having been infected with dengue previously or who are willing to undergo serological testing (Dengue IgG) to prove that they have had the infection in the past. A risk assessment will be conducted to ensure that you are suitable for the vaccine and serological testing is highly recommended to gauge your suitability for the vaccine.
• Who should not get the vaccine? Those who have not previously been infected with dengue fever are NOT recommended to receive the vaccine. They are at risk of developing a severe form of dengue which can lead to serious complications and even death.

Still not sure if you can have the dengue vaccine? If you are living in an area that is a dengue cluster or if you are travelling to countries that have experienced Dengue outbreaks, it is best to give us a call at 8754 4101 or send us an e-mail at mparam@202.164.42.26 to find out if you are suitable for the vaccine and also for methods to protect yourself from the disease. If you book in for a consultation with us, you can receive the dengue vaccine only after a risk assessment and after either providing records that you have been infected with dengue previously or after undergoing serological testing that an prove that you have been infected in the past.