The medical expert review panel from the Philippine General Hospital has come out with its findings regarding the deaths of children who received the dengue vaccine. The physicians said only three deaths, out of 14 alleged Dengvaxia-caused deaths, were found with ‘causal association.’

“In three cases, causal association was observed. The children died due to dengue despite being vaccinated with Dengvaxia - two of which may be on account of vaccine failure,” Department of Health Undersecretary Enrique Domingo told reporters in a press conference on February 2, at the DOH Central Office.

The panel's report found two deaths were unclassifiable because of insufficient data, while three deaths were tagged as “coincidental because there was inconsistent causal association to immunization.”

The other six deaths were found to have unscreened comorbidities. The PGH panel suggested further testing involving the tissue samples to complete the investigation.

Dr. Domingo said the PGH findings strengthened the decision of DOH to suspend the vaccination programme, and whether they will suggest the DOH to declare vaccine failure.

Health Secretary Francisco Duque III immediately declared to stop vaccination in November shortly after Sanofi Pasteur, the dengue manufacturer announced new information that severe dengue may result for those without prior infection.

"We stopped it. We are not sure yet (vaccine failure). We will still need to study this vaccine further," the Health official said, adding, "it's just vaccine failure in two or three cases, not for all the 830,000."

The PGH findings will be submitted to the Department of Justice (DOJ) and to the DOH’s Pharmacovigilance team for evaluation of any new potential relationship of adverse event and vaccination.

PGH expert panel slide defining vaccine failure

PGH expert panel slide defining vaccine failure

PGH-Dengue Investigative Task Force

PGH Director Dr Gerardo Legaspi, present at the briefing, said it took them long to find specialists to conduct the review as the two strict requirements are non-affiliation to any pharmaceutical company and having never administered the dengue vaccine to any of their patients.

The panel review, headed by PGH Paediatric Department Head Dr Juliet Sio-Aguilar, was composed of 10 members: two paediatric cardiologists, two paediatric infectious disease specialists, one paediatric emergency specialist, one allergist immunologist, one paediatric gastroenterologist, one neonatologist and one forensic pathologist.

There were four sub-specialties which were care-based, this includes paediatric neurologist, paediatric hematologist-oncologist, geneticist and a rheumatologist.

“The specialists received no remuneration. Their only request is to remain anonymous to maintain their independence and [to prevent] outside pressure,” said Dr Legaspi.

Dr Sio-Aguilar said that the panel members were divided into two teams and reviewed seven cases each. The panel then held a plenary session to discuss the cases.

Review highlights

For their review, Dr Sio-Aguilar said they used the World Health Organization (WHO) Causality Assessment of Adverse Event Following Immunization (AEFI), as it is a “systematic, standardized, global process for evaluating whether an incident or outcome is related to any vaccination.”

Causality assessment, the panel clarified, will not prove or disprove a link between an event and the immunization. It is meant to determine the “level of certainty of such association.”

As for the three deaths found with causal association, Dr Aguilar said Patient Data #1 [patient] died of dengue shock syndrome. The patient presented with clinical signs, symptoms and course consistent with dengue shock syndrome. The patient died five days after the onset of illness. The patient was NS1 positive; Dengue IgM and IgG negative.

“We want to know why the patient was not protected even after 3 doses,” said Dr Sio-Aguilar. Their recommendation is for tissue evaluation for polymerase chain reaction (PCR) and antibodies for yellow fever and dengue viruses.

“The second case is one who had dengue shock syndrome four days after the first dose...we thought that the progression was too fast - even the patient’s liver was affected. The patient died after five days,”’ she said. The second patient was NS1 positive; IgM and IgG negative.

“We thought that the patient could have been incubating an infection even before vaccination,” Dr Sio-Aguilar explained. Again, they recommend tissue evaluation for PCR and antibodies for yellow fever and dengue virus.

The panel tagged the third case with causal association as either vaccine failure or due to another cause. The patient had dengue shock syndrome and presented with clinical symptoms. The patient died six days after illness onset. (NS1 positive; Dengue IgM; Dengue IgG positive)

“The third was an unusual case, the patient was IgG positive, which was usually protective, so why otherwise?” said Dr Sio-Aguilar. Likewise, the panel recommend tissue evaluation for PCR and antibodies for yellow fever and dengue viruses.

Dr Sio-Aguilar noted that the panel also has recommendations for the other cases.

One of the results of expert panel review on dengue vaccine-related deaths.

One of the results of expert panel review on dengue vaccine-related deaths.

Public assurance

“The department will continue to strengthen its Dengue Prevention and Control Program  and Control Program and collaborate with other agencies of government such as the Department of Education and local government so that we can continue to safeguard the welfare of the vaccinated children,” said Undersecretary Domingo.

He reminded the parents that hospitalization costs of the affected children will be shouldered by PhilHealth, and to consistently practice the 4S preventive measures against dengue as there is no full protection against dengue.

DOH and the PGH panel called on the medical and scientific community to stress that correct information must be disseminated, to clarify misconceptions and to use only evidence-based information on dengue. MIMS 

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