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Overreaction to dengue vaccine issue could derail our immunization programs


By Eduardo Gonzales, MD

What can you say about the ongoing discussion on the dengue virus vaccine? Is there a real reason for the public to be alarmed?—euna_elbo@yahoo.com

The parents of the more than 830,000 children (not 730,000, as initially reported) who have received the dengue vaccine (Dengvaxia) have reasons to be alarmed in the light of the announcement by Sanofi Pasteur, the manufacturer of the vaccine, that their vaccine could worsen the disease in some cases. The disinformation and finger-pointing that followed the announcement has, however, blown the issue out of proportion. This could derail our other immunization programs (DPT, measles, polio, etc.) because Filipino parents might increasingly believe that vaccines are harmful and refuse to vaccinate their children in the same manner that many American parents are refusing to vaccinate their children in the light of fake research studies that suggested the MMR vaccine causes autism.

Vaccines are the main reason our mortality rate among infant and children has gone down dramatically in the last few decades. It is a pity if we lose all we have gained because we choose to overreact even before we know the facts.

Dengue and The Sanofi Turnaround

Dengue is a mosquito-borne disease that can be caused by any of the four serotypes of the dengue virus. Thus, people can get ill with dengue not just once but as many as four times in their lifetimes.

When it was released, Sanofi Pasteur claimed that Dengvaxia, a quadrivalent vaccine, can protect individuals against the four types of dengue viruses. Hence, it was recommended for all people who are in the nine to 45 years age bracket.

Last month, however, Sanofi Pasteur made a turnaround on its recommendation. It said that based on up to six years of clinical data, new analysis confirmed that Dengvaxia provides persistent protective benefit against dengue fever in only those who had prior infection with dengue. For those not previously infected by dengue virus, more cases of severe disease could occur following vaccination upon a subsequent dengue infection. In other words, Dengvaxia should be administered only to those who have been previously infected with the virus. It should not be given to individuals who have not been previously infected because they will have a higher risk for severe dengue if and when they get naturally infected with the virus.

The Dengue immunization campaign of the Department of Health (DOH) has thus placed those who have not had prior dengue infection before they were immunized in danger of getting severe dengue in case they get naturally infected with the dengue virus. How many of the more than 800,000 children have had no previous dengue infection is unknown. We need to blood test everyone to find out, and this is impractical and very expensive. We, however, take comfort in the fact that as many as 90 percent of Filipinos have been infected by dengue by the time they become adults, which implies many of these 800,000 children have already been previously infected with dengue.

Our fears should likewise be allayed by the fact that, as mentioned by Dr. Julius Leccioness, chief of the Philippine Children’s Medical Center, the other country that also embarked on mass vaccination, Brazil, reported no severe cases attributable to Dengvaxia and decided to continue its program. Likewise, Health Secretary Francisco Duque III has said that there has been no “severe” case among those who had already been vaccinated.

Unanswered Questions

Sanofi has not provided us with an answer on how and why it is possible for a person who has been immunized with the vaccine that is supposedly protective against the four types of dengue virus can still get infected with dengue. We can only surmise that it has something to do with the limitations of the vaccine—it does not give 100 percent protection, it protects just two-thirds (66  percent) of individuals who get the vaccine.

In so far as the DOH is concerned, the big question is why it undertook a massive immunization campaign that costs R3.5 billion despite the strong reservations expressed by a group of Filipino doctors and scientists on the safety of the vaccine, especially because such a campaign will definitely not eliminate dengue from the Philippines—according to a study by the University of the Philippines National Institutes of Health, the vaccine is expected to reduce dengue cases in our country by only over 24 percent in a span of five years.

With so many unanswered questions, it is probably right that the DOH has suspended its dengue immunization program and stopped the sale of the vaccine in the Philippines until the facts on the safety and efficacy of the vaccine are completely analyzed by experts. The World Health Organization (WHO) has been consulted on the matter. The plan to closely monitor all those who have been immunized is also laudatory.

In the meantime, let’s tone done on our rhetoric. It may backlash on our other public health programs.

Email inquiries on health matters to: medical_notes@yahoo.com

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