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Dengue expert: Dengvaxia diagnosis cannot be based on autopsy


A leading figure in dengue research said Monday that an autopsy cannot be the basis for linking Dengvaxia to the death of a child who received the vaccine.

“Please be aware that the diagnosis of Dengvaxia cannot be based on an autopsy,” US doctor Scott Halstead said during the Senate Blue Ribbon Committee probe into the vaccine, which had been given to 830,000 students by the time the immunization program was suspended last December.

“There are a lot of autopsies being done now because, of course unfortunately, children die for one reason or another after vaccine. This is a very old phenomenon. I’ve been in the vaccine business forever and there are always problems like this,” Halstead added.

According to the US Centers for Disease Control website, Halstead is an adjunct professor in the Department of Preventive Medicine and Biostatistics of the Uniformed Services University of the Health Sciences, a health science university of the US government. He founded the Pediatric Dengue Vaccine Initiative in 2003 as a consultant to the Rockefeller Foundation, and serves as its research director and senior advisor.

The Public Attorney’s Office has been conducting autopsies on children who had been given doses of Dengvaxia.

PAO forensic consultant Erwin Erfe earlier said that bodies they examined showed enlargement of different organs and bleeding in some parts of the body.

Unequivocal evidence

Halstead said that for any child who receives Dengvaxia doses and later dies, two things have to be considered before concluding that the two are connected:

  • unequivocal evidence that the infection was caused by dengue virus, which can be done by either virus isolation or identification of NS1; and
  • knowing if the particular individual was given the vaccine when he or she was seronegative or seropositive.

“To do that, we need to use the test that Sanofi has developed and available in several laboratories and hopefully they introduce it to the Philippines,” he said.

Halstead added that “it is not appropriate to use the terms viscerotropism and neurotropism in relation to Dengvaxia.”

"Viscerotropism" is a medical term defining an effect on the body’s internal organs, usually the heart, lungs and liver; while "neurotropism" refers to an effect on the nerves.

He said the two terms are applied to yellow fever vaccine, which was introduced in 1937.

“It has two properties. If you give it to young children, the vaccine actually causes encephalitis; that's the neurotropic aspect of yellow fever vaccine. But if you give it to millions of people—once in a while, people who are otherwise healthy get yellow fever. We don’t have any idea why. It is very strange and mysterious. We exerted a lot of effort to try to understand what is going on—that reaction is called viscerotropic,” he said.

He said from everything they know, Dengvaxia does not cause any illness whatsoever, but he admitted that what they are dealing with is a unique situation.

Halstead noted that 40 to 50 years ago, the US marketed a measles vaccine. Two years after the vaccine was administered, children acquired very severe measles and then died.

He said it is the immune response to the vaccine that leaves a person at risk to a much more severe disease.

“Remember that it is not the vaccine that we are talking about here, it is the anti-bodies to the vaccine, it is what is left over after you have been vaccinated [that affects the body],” Halstead said.

He maintained that Dengvaxia is effective in protecting people who are seropositive or have had prior dengue immunity, but not effective in preventing disease in people who are seronegative at the time they were vaccinated.

Halstead earlier said that a test to determine if a person is seronegative or seropositive should have been done first before Dengvaxia was administered.

"We don’t want people to feel that vaccines are dangerous," he said.

"I’ve been a pro-vaccination all my life. We do not want vaccines to be injured by this. The children who are at risk now, I hope we dedicate to getting these children to clinical care early. Parents come in early and physicians know how to handle them." — BM, GMA News

Tags: dengvaxia, dengue
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