The U.S. Food and Drug Administration just approved one of the most sought after vaccines in recent decades. It’s the world’s first vaccine to prevent dengue fever — a disease so painful that its nickname is “breakbone fever.”
The vaccine, called Dengvaxia, is aimed at helping children in Puerto Rico and other U.S. territories where dengue is a problem.
But this vaccine has a dark — and deadly — history. One that has led to criminal charges in the Philippines, and sparked national panic.[E]stimates are that more than 100,000 Philippine children received a vaccine that health officials say increased their risk of a severe and sometimes deadly condition. In addition, other children who received the vaccine may have been endangered because, their parents alleged, they were not in good health.
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 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.
[H]e 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.
“Then everything gets worse, and maybe it’s impossible to save your life,” Halstead says. “A child can go into shock.”
“The trouble is that the disease occurs very rapidly, just in a matter of a few hours,” he adds. “And there’s nothing on the outside of the body to signify the person is leaking fluid on the inside.”
“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.”
The vaccine manufacturer disagreed with Halstead’s interpretation of the study’s results. The company wrote a rebuttal, asserting that regulatory agencies had approved Dengvaxia “on the basis of the vaccine’s proven protection and acceptable safety profile.”
Despite these concerns, in July 2016, the World Health Organization went ahead and recommended the vaccine for all children ages 9 to 16.
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.
Panic hit the Philippines. In news reports, parents said that the vaccine contributed to the deaths of 10 children.
Protests erupted. The Congress of the Philippines launched investigations into the vaccine’s purchase and the immunization campaign. And Philippine health officials started performing autopsies on children who died after receiving the vaccine.
“In total, the deaths of about 600 children who received Dengvaxia are under investigation by the Public Attorney’s Office, ” the South China Morning Post reported last month.
WHO eventually changed its recommendation. The agency now says the vaccine is safe only for children who have had a prior dengue infection.
By the time Sanofi acknowledged this problem with the vaccine, about 800,000 Philippine children had been vaccinated. The Sanofi study estimated that more than 100,000 of them had never been infected with dengue and should not have received the shot, according to WHO’s revised recommendation.
Here in the U.S., the approval of the vaccine — to be used in Puerto Rico, the U.S. and British Virgin Islands and Guam — comes with an important restriction: Doctors must have proof of a prior dengue infection to ensure the vaccine will not pose any risks to the child.
That’s a safeguard Philippine families never had.
Read the full article at NPR.org