The Philippines Suspends Dengue Vaccine Amid Safety Review

The dengue vaccine is a key disease prevention strategy across the world, but a new safety review has prompted concern in the Philippines. Now, vaccine producer Sanofi has requested an updated label to make the risks clear. 

CNN reports:

The Philippines has suspended its large-scale dengue vaccination effort amid the surprising results of a new study conducted by the vaccine’s manufacturer.

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On Monday, Harry Roque Jr., a spokesman for Philippines President Rodrigo Duterte, announced that the Department of Justice would launch an investigation into the fast-track approval of Dengvaxia by the previous administration. Assistant Health Secretary Lyndon Lee Suy said his agency would work with the Department of Education to monitor all recipients of the vaccine for adverse health effects.

At first glance, the vaccine — known as Dengvaxia — appears to have been a significant success for the French drug firm, so what went wrong?

The answer lies in the vaccine recipient’s health history.

Dengue fever: a serious threat to childhood health

Dengue fever is a mosquito-transmitted illness that can lead to a dangerously high fiver, severe headaches, pain, vomiting, heart stress and heart attack, among other symptoms. While proper treatment can ensure that people recover, the high fever risk and the potential for neurological impairment makes proactive, preventative steps critical — particularly to shield children.

That’s where the Dengvaxia vaccine, the first vaccine ever approved to specifically treat dengue fever, has proved to be an important safe-guard for nations in some Latin American and Asian countries, like the Philippines and Brazil. To date, it’s estimated that about one million people — many of them children — have received a dose of the drug. According to the BBC, that number includes 730,000 children in the Philippines.

And the vaccine has proved successful, with a 65.6 percent efficacy in preventing hospitalization among older children and a considerably greater preventative power among children who showed signs of previous dengue infection.

That variable, though, is where Sanofi has now identified a problem.

Potential for serious post-vaccine dengue symptoms emerges

As part of their ongoing commitment to ensuring public health, drug firms routinely carry out reviews and studies of how their vaccines and other products. While these pharmaceutical companies perform real-world trials prior to product launch, data must be collected over many months and even years to know the true impact of a drug or vaccine.

After a review of six-years of clinical data, Sanofi has found that the vaccine doesn’t protect everyone equally.

Sanofi press release summarizes the findings:

… the new analysis evaluated long-term safety and efficacy of Dengvaxia in people who had been infected with dengue prior to vaccination and those who had not. The analysis confirmed that Dengvaxia provides persistent protectiv [sic] benefit against dengue fever in those who had prior infection. For those not previously infected by dengue virus, however, the analysis found that in the longer term, more cases of severe disease could occur following vaccination upon a subsequent dengue infection.

At this time, there have been no confirmed deaths that can be attributed to the vaccine’s use, despite several emerging reports.

Nevertheless, Sanofi is requesting a label update to its Dengvaxia product, stating, ”for individuals who have not been previously infected by dengue virus, vaccination should not be recommended” and suggesting that doctors assess risk factors before recommending the vaccine.

With this news, the World Health Organization has also updated its guidelines for the vaccine.

The organization states that the vaccine “significantly protects against hospitalized and severe dengue in individuals” who test positive for previous dengue fever infection when they are vaccinated.

However, it notes that “The risk of hospitalized and severe dengue is significantly increased among vaccinated individuals” who test negative at time of first vaccination.

Therefore, they state: “Pending the full review of the data, as a precautionary and interim measure, WHO recommends that Dengvaxia® is only administered to individuals that are known to have been infected with dengue prior to vaccination.”

WHO data suggests that a disparity in effectiveness and potential health impacts had emerged in clinical data before the vaccine was approved. However, government officials in the Philippines claim that they were unaware of any potential risk.

Meanwhile, Singapore’s health ministers allegedly flagged this possible risk so that their doctors were aware of potential problems. Some public health advocates in the Philippines are pushing for an internal review to explore this potential oversight.

In the meantime, wider health authorities are stressing that there is no evidence of a rash of “severe dengue” cases since the vaccine was administered. And with these variables in mind, the dengue vaccine continues to be an important health intervention.

Photo credit: Thinkstock.

19 comments

Linda D
Linda D2 days ago

Wouldn't it be better if children got better nutrition therefore there immune systems could fight off the disease, that is how nature intended it. Vaccines do not work, never have, they are lying all the time about their so called studies. So much stagnated water sitting around in poor areas due to the shambles and no fresh water supply or proper sewerage, this would get rid of these diseases not vaccines.

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Anne M
Anne M2 days ago

Damn bugs !!

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Cruel Justice
Cruel J2 days ago

Frightening to say the least.

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Lisa M
Lisa M2 days ago

Noted.

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Lisa M
Lisa M2 days ago

Noted.

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Sherry Kohn
Sherry K3 days ago

OMG !

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Jonathan H
Jonathan H3 days ago

Noted!!!!

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Tania N
Tania N3 days ago

Thank you.

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Janet B
Janet B3 days ago

Thanks

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Lenore K
Lenore K3 days ago

ok

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