ONE of the acknowledged foremost experts in dengue research in the world had tried to forewarn Philippine authorities on the use of Dengvaxia vaccine on children who had never contracted dengue, but the government ignored him.
Dr. Scott B. Halstead, an 87-year-old US-based scientist, sent a video recording of his warning in December 2016 to the Senate Blue Ribbon Committee, then investigating questions on the procurement of 3-billion pesos worth of vaccines manufactured by Sanofi-Pasteur, a French Pharmaceutical company, but the video was never played before the Senate hearing.
First to raise alarm bells
In an exclusive interview with ABS-CBN News, Halstead recounted how in 2016, he became “very worried” about the plan of Philippine health officials to embark on a massive school-based dengue immunization program using Sanofi-Pasteur’s vaccine.
Halstead first issued the warning—that Dengvaxia should not be administered to seronegative individuals, or people who had never been infected with the dengue virus—in an international medical journal called Vaccine on March 29, 2016.
Vaccine’s editorial board consists of scientists and doctors from the United States, United Kingdom, Japan, the Netherlands, Switzerland, Italy, Spain, and India, among others.
So when he learned about the ongoing immunization program from Philippine colleagues, Halstead tried to stop the vaccination of seronegative individuals. He sent the video through local health advocate Dr. Antonio Dans, hoping the Blue Ribbon committee would listen to his plea and help avert the program.
On December 6, 2016, Dans presented Halstead’s credentials and a summary of his message, according to Senate transcripts, but he failed to play the video.
Solution to the problem
The video, which Halstead shared with ABS-CBN News this week, showed him explaining the benefits and risks of the dengue vaccine.
“When given to somebody who has had one or more dengue infections, Dengvaxia boosts the immunity status and one is fairly protected. That’s wonderful,” he said. “If you’re seronegative…and you get vaccinated, your first infection may put you in the hospital, and maybe worse.”
Halstead offered Philippine officials a simple, if somewhat costly solution: Pre-screen the individuals queuing for the vaccine.
Don’t give the vaccine to seronegative children, he said. Instead, give the vaccine to those who had contracted dengue before.
Problem could have been averted?
It was unclear if then Health Secretary Paulyn Ubial, who was present at the Senate hearing, had seen Halstead’s video.
Had she done so and heeded Halstead’s warning, some 36,800 children—or 10 percent of 368,000 vaccinated in 2017, based on government estimates—there wouldn’t be fear that they are at risk of severe dengue today.
Before Ubial, there was Secretary Janette Garin who also could have heeded Halstead’s warning. Garin launched the dengue immunization program in April 2016, days after of the publication of Halstead’s study.
If the children had been tested, some 49,000 children—or 10 percent of 491,990 vaccinated in 2016—would not be at risk of severe dengue.
The Elisa test
Asked why none of the children vaccinated under her watch were screened, Ubial said it was a cost issue.
“It would have been very tedious and expensive, and it would negate the cost-effectiveness of the intervention. Besides we had other data that infection rate was high,” she said.
Garin said the existing tests were non-specific. Testing positive could mean one had been infected with dengue or other flavi-virus like chikungunya, Zika or Japanese encephalitis, she said.
But Halstead dismissed all that.
“It’s not true that there are no tests to determine if an individual has previously had dengue. It’s called the Elisa test and it’s been around for about 20 years. You have a lot of options,” he said.
No ordinary man
Why Garin and Ubial seem to have ignored Halstead’s warning remains unclear.
Halstead is no ordinary scientist.
Halstead, according to science publications, is one of the world’s leading experts in dengue research.
He began studying mosquito-borne viruses 60 years ago while serving the US Army Medical Corps in Asia. He has since published 189 articles on the dengue virus.
A co-founder of the Children’s Vaccine Initiative together with UNICEF, the World Bank and the WHO, Halstead also founded the Pediatric Dengue Vaccine Initiative (PDVI) in 2002, which the Rockefeller Foundation and the Gates Foundation funded.
Even Sanofi-Pasteur, the manufacturer of Dengvaxia, must have thought Halstead’s work was credible. In 2006, it formed a partnership with PDVI to develop a vaccine for the global prevention of dengue.
Ironically, in August 2016, the French pharmaceutical giant wrote Vaccine to criticize Halstead’s study where he identified the risks of administering Dengvaxia to seronegative individuals.
It took another fifteen months, on November 29, 2017, before Sanofi-Pasteur released independent findings that confirmed Halstead was right all along.
“What I said two years ago is exactly what Sanofi is saying now,” Halstead said.
Where have all the brave scientists gone?
Halstead would have felt vindicated about Sanofi-Pasteur’s admission two weeks ago, but he is still mad at the drug manufacturer, asking why it took the company so long to warn the public.
He is angry at a lot of people.
“The list goes beyond Sanofi. The World Health Organization saw the same data that I saw, but they came to a completely opposite conclusion. I’m also angry at my fellow dengue scientists. Where are all those brave scientists?” he asked.
Halstead said he would be willing to travel to the Philippines and appear at the Senate hearings if invited.
For now, he urged government to identify the children who were seronegative at the time of vaccination.
“Put them on a special watchlist,” he said. “Alert their parents, the doctors and their schools. Make sure you know who they are. That’s really the only thing you can do now.”