What is Dengue Fever?

Dengue is a mosquito born illness, endemic throughout the tropics and subtropics. It is a leading cause of fever inducing illness for travelers to Latin America, the Caribbean, and Southeast Asia. Dengue exists in over 100 countries, including Puerto Rico, the US Virgin Islands, and US-affiliated Pacific Islands. Sporadic outbreaks with local transmission have occurred in Florida, Hawaii, and Texas along the Mexican border.

Approximately 40%–80% of infections are asymptomatic. Symptomatic infection is a generally mild to moderate, nonspecific, acute febrile illness, a flu-like disease that can cause joint pain, nausea, vomiting and a rash. However, unlike many illnesses where the immune system creates antibodies to protect against recurrence, people who catch dengue a second time can be at risk of the hemorrhagic version of the disease characterized by breathing problems, hemorrhaging and organ failure. As many as 5% of all dengue patients, particularly children, develop severe disease.

According to the World Health Organization (WHO), about half the world’s population is at risk of dengue, about 96 million people are sickened by it annually, and about 20,000 die¹′².

Dengue Fever vaccine dangers identified and disregarded

A 2016 Philippines dengue fever vaccine campaign was expected to save children’s lives and prevent an estimated 10,000 hospitalizations over a five year period. Instead, the campaign was halted because it was sickening and killing children. The vaccine, rushed to market and targeted to children 9-16 years of age, was approved by the WHO despite the warnings of a US military scientist who had been studying dengue fever for 50 years and saw the warning signs in the manufacturer’s clinical trial data. Here’s what happened:

The French pharmaceutical company Sanofi Pasteur spent 20 years — and about $2 billion — to develop Dengvaxia. The company tested it in several large trials with more than 30,000 kids globally and published the results in the prestigious New England Journal of Medicine.

But halfway around the world from the Philippines, in a Washington, D.C., suburb, one scientist was worried about the new vaccine.

“When I read the New England Journal article, I almost fell out of my chair,” says Dr. Scott Halstead, who has studied dengue for more than 50 years with the U.S. military. When Halstead looked at the vaccine’s safety data in the clinical trial, he knew right away there was a problem.

For some children, the vaccine didn’t seem to work. In fact, Halstead says, it appeared to be harmful. When those kids caught dengue after being vaccinated, the vaccine appeared to worsen the disease in some instances. Specifically, for children who had never been exposed to dengue, the vaccine seemed to increase the risk of a deadly complication called plasma leakage syndrome, in which blood vessels start to leak the yellow fluid of the blood.

“Then everything gets worse, and maybe it’s impossible to save your life,” Halstead says. “A child can go into shock.”

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The complication is rare, says Halstead. Still, he was so worried about the safety concerns that he wrote at least six editorials for scientific journals. He even made a video to warn the Philippine government about the problem.

“I just think, ‘No, you can’t give a vaccine to a perfectly normal, healthy person and then put them at an increased risk for the rest of their lives for plasma leakage syndrome,’ ” Halstead says. “You can’t do that.”

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Despite these concerns, in July 2016, the World Health Organization went ahead and recommended the vaccine for all children ages 9 to 16.

“Yes, we did. It was what we call a ‘conditional recommendation’ with the emphasis to minimize potential risks,” says Dr. Joachim Hombach, who led WHO’s review of the vaccine. “We saw the problems. We also clearly pointed to the data gaps.”

WHO recommended that Sanofi do more experiments to better understand the vaccine’s safety issues. In its assessment, WHO pointed out that the vaccine “may be ineffective or may theoretically even increase the future risk of [being]hospitalized or severe dengue illness” in people who have never been exposed to dengue — which is about 10% to 20% of Philippine children.

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In November 2017, Sanofi published an announcement on its website saying it had new information about Dengvaxia’s safety.

Halstead’s fears were confirmed. Sanofi had found evidence that the vaccine increases the risk of hospitalization and cytoplasmic leakage syndrome in children who had no prior exposure to dengue, regardless of age.

“For individuals who have not been previously infected by dengue virus, vaccination should not be recommended,” the company wrote.

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Typically, a vaccine works by triggering the immune system to make antibodies against the virus. These antibodies then fight off the virus during an infection.

But dengue is a tricky virus. Dengue antibodies don’t always protect a person. In fact, these antibodies can make an infection worse. The dengue virus actually uses the antibodies to help it spread through the body. So a second infection with dengue — when your blood already has antibodies in it — can actually be worse than the first; a person is at a higher risk of severe complications like plasma leakage syndrome³.

Phillipine Government, FDA, and vaccine company officials held responsible

The Panel of Prosecutors who conducted the preliminary investigation on the deaths of children allegedly linked to the administration of the Dengvaxia vaccine has found probable cause to indict former Department of Health (DOH) Secretary Janette L. Garin and nine (9) other DOH officials, along with officials of the Food and Drug Administration (FDA), Research Institute for Tropical Medicine (RITM), and Sanofi Pasteur, Inc. (Sanofi), for reckless imprudence resulting to homicide.

In its 127-page Resolution dated 11 February 2019 and officially released on 27 February 2019, the Panel found Garin and the other respondents to have exhibited “inexcusable lack of precaution and foresight” when they facilitated, with undue haste, “the registration and purchase of Dengvaxia” and used the vaccine in implementing a school-based dengue mass immunization program.

The Panel found sufficient evidence that Garin and the other respondents circumvented various regulations in the purchase of P3.5B worth of Dengvaxia vaccine which constituted proof of their reckless imprudence⁴.

It was found that some children were given the vaccine by untrained health workers and allegedly without a proper physical beforehand. Some children were inoculated despite having allegedly had preexisting medical conditions that made the immunization dangerous. Sanofi officials were also indicted for not properly helping children who had serious reactions to the shot ⁵.

Dengavaxia today

The vaccine is only recommended for persons who have already had a verified case of dengue fever.

Additional resources:

• Reuters in Manilla, Suspended dengue vaccine was given to 730,000 children, Philippines says, https://www.theguardian.com/world/2017/dec/05/suspended-dengue-vaccine-children-philippines-sanofi
• Micronutrients and Dengue, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4228873/
• Dengue prevention: Foods to eat and avoid, https://timesofindia.indiatimes.com/life-style/health-fitness/diet/dengue-prevention-foods-to-eat-and-avoid/articleshow/70466703.cms
• Food for Dengue – What to Eat and What to Avoid!, https://pharmeasy.in/blog/food-for-dengue-what-to-eat-and-what-to-avoid/