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Should you get vaccinated?

5 things you need to know about Dengvaxia, the world’s first dengue vaccine


On Monday last week, the Department of Health (DOH) officially kicked off its public, school-based dengue immunization program, the first in the world, at the Parang Elementary School in Marikina, where over 600 grade four students lined up to receive the first of three doses of Dengvaxia, the much-touted breakthrough dengue vaccine by French pharmaceutical giant Sanofi Pasteur.

This year, the government aims to inoculate one million school children from 6,000 preselected schools belonging to Regions 3, 4, and Metro Manila, where the highest incidences of dengue occur, in an ambitious P3.5 billion project.

At the press conference, Health Secretary Janette Garin called the program’s launch “a historic milestone.” She said, “We are the first country to introduce, adopt, and implement the first-ever dengue vaccine through (the) public health system and under a public school setting.”dengue vax

But as early as February, private physicians have already started ordering the vaccines from Sanofi. There are initially 300,000 doses available for the private market in the country.

On social media (and in tight mommy circles), warning bells have been rung against the premature administration of a vaccine that has not been given the go-signal by the World Health Organization (WHO), not just by worried parents but also by a few members of the medical community. And the excitement over the arrival of an urgently needed vaccine—the Philippines registers the highest number of cases in the Western Pacific region in the period covering 2013 to 2015—has been muddled with the fear that said vaccine might cause more harm than good.

It is equally alarming, however, to note that the Philippines holds the distinction of having the most incidence of dengue in the endemic countries that have held clinical trials. Last year, we had 200, 415 confirmed cases. As of Feb. 20, a total of 18,790 suspect dengue cases have been reported nationwide—a figure that is 13.2 percent higher compared to the same period last year. More than three billion people worldwide are at risk of getting dengue.

If you’re seriously considering the dengue vaccine to protect yourself or your children, here are facts you need to know about Dengvaxia to help you make an informed decision.

Sec. Janette Garin injects the first student to get the dengue vaccine during public, school-based vaccination program

Sec. Janette Garin injects the first student to get the dengue vaccine during public, school-based vaccination program


1. While the WHO has not released guidelines and recommendations for its use, the local Food and Drug Administration has approved Dengvaxia.

The greatest misconception (and fear) surrounding Dengvaxia stems from a misunderstanding about which agencies have the power to approve the use of a vaccine or a medicine in the country.

Some doctors have questioned its safety and efficacy, and are strongly calling out the government for its implementation without the WHO Strategic Advisory Group of Experts’ recommendations.

In a press briefing held four days before the mass vaccination, WHO country representative Dr. Gundo Weiler said that the organization was supportive of DOH’s program. He said, “It is the prerogative of a country to license the product, determine its use based on the internal scientific appraisal of the clinical research underpinning the product.”

The council only meets twice a year, which has impacted the timing for the release of the WHO recommendation, expected this April. The publication of the recommendation, explained Weiler, had been delayed. He elaborated that “it is not the WHO’s mandate to license a medical product, to determine whether or not a product should be used in a country. This is the prerogative of the national regulatory authority in the country.”

The FDA has approved the sale of the drug in the country last Dec. 22, which makes the Philippines the first country in Asia, and the second in the world (Mexico has the distinction of being the pioneer), to give regulatory approval for the drug. That list is now updated to include two more countries, Brazil and El Salvador.


2.  Dengvaxia is not for everyone.

The vaccine can fight against four dengue strains, although effectiveness varies per serotype, and is recommended to be given in three doses at six-month intervals (0-6-12) to healthy individuals between the ages of nine and 45.

The vaccine has been evaluated in three phases, and kids below nine years old have also been part of the clinical trials.  Studies include a follow-up for one year after the last dose of vaccine in the series, and a hospital-based follow-up period of four years.

The reason the vaccine is limited to this particular age group is because, simply put, efficacy is shown to be higher and fewer side effects have been noted.

When limited to older age groups (ages included in the current licensure), pooled vaccine efficacy among all participants aged nine years or over was 65.6 percent, and in participants younger than nine years old it was 44 percent, as stated in the WHO website.

And because this vaccine is a live, attenuated one, it cannot be given to people with compromised immunity, such as those taking medications that suppresses normal immunity like HIV/AIDS patients and post transplant patients.

As for concerns on side effects,  Dr. Rose Capeding, lead researcher for the Philippine clinical trials, notes that there was no difference on the side effects reported by those who were given the vaccine and the placebo, which means that pain in the site of injection, redness, and fever presented in both kinds of participants.


3. Dengvaxia is more effective in some strains, less effective in others.

According to the WHO website, vaccine efficacy was higher against serotypes 3 and 4 (71.6 percent and 76.9 percent respectively) than for serotypes 1 and 2 (54 percent and 43 percent). Vaccine efficacy also varied by age at vaccination. So what does this mean for us? The nature of dengue is that a second infection often hits harder than the first one, putting people at greater risk for a more severe infection down the road.

This is a big cause of worry for most parents: The serotype 2 efficacy isn’t as high, and it may be upsetting to note that serotype 2 is one of the more—if not the most—common kind of dengue serotype in recent times.

Sanofi Pasteur representatives, as well as Dr. Capeding, who also heads the Department of Microbiology at the Research Institute of Tropical Medicine, assure the public that the most important advantage to the vaccine is that it reduces, by 93 percent, severe dengue cases (or Dengue Hemorrhagic Fever). Clinical trials have also shown that it reduces dengue in two-thirds of the participants and prevents eight out of 10 hospitalizations.

Sec. Garin says, “There is no 100 percent guarantee that you will not get sick of dengue, but there will be drastic reduction in the severity of your dengue. The dengue will devolve into a minor type that will not require hospitalization.”


4.  Dengvaxia has been intensively researched and tested.

Although dengue as a disease has only become a global threat recently—it has had a 30-fold increase since it was first reported in modern times (in 1953 in the Philippines)—global researchers from Sanofi have been trying to find solutions to the pandemic over the past two decades. About 40,000 people have undergone clinical trials in 15 countries, and 29,000 of them have been injected with the actual vaccine (the rest have been injected with placebo).

Research and production of a dengue vaccine has been extremely difficult because the scientists needed to find a way to address all four serotypes without the risk of adverse reactions, and the vaccine had undergone three phases for the clinical trials. In the Philippines, the clinical trials were conducted in San Pablo, Laguna and Cebu.

The Philippine Pedriatic Society, with its sub-specialty societies, The Philippine Foundation for Vaccination, the Pedriatic Infectious Disease Society of the Philippines, and the Philippine Society of Microbiology and Infectious Diseases have all welcomed its arrival in the country.

Gulliame Leroy, Sanofi Pasteur’s vice president, said that Sanofi has already invested an estimated $1.3 billion since it started research on the project, with about $480 million of that in the building of a huge dengue research facility in France, which is considered by the company as its biggest single investment.


5. As with all new vaccines, we do not have answers to some important questions.

It is, for example, unknown how long the measured protection against dengue will last with the vaccine, although some studies show that five years after being injected, antibodies are still high in participants.  According to the World Health Organization, “prolonged monitoring in both Asian and Latin American trials, as well as post-licensure studies,will be needed to measure long-term safety and efficacy, including whether there is any waning of protection over time.”

We also cannot completely answer the question about when we will start to see the effectiveness of the vaccine.

“Not right away, it will take some time,” Sec. Garin said during the press conference at Parang Elementary School. “It will be measured as the years come. When one child is protected, we eliminate one source of infection, and if we multiply it for every child injected, we drastically cut the chance that dengue will spread.”