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Postnormal science and the dengue vaccine controversy

While science can explain much about the natural world and has resulted in technological advances that makes life better, it has uncertainties. Any scientific and technological application in our daily lives has risks.
The job of scientists, most especially statisticians, to is make sure these risks are at a manageable level. The medical and environmental sciences are two disciplines in which the conclusions of these sciences intimately affect our personal lives and that of our loved ones. The applications of these sciences in daily life, entail risks. A good medical doctor should be able to advise you of the risks of side effects of a drug. Likewise a good environmental scientist should be able to advise you of the risks of using environmentally damaging technologies.
While environmental scientists and doctors of medicine can come up with the scientific theories of their disciplines, applying these in society is another matter. The application of these becomes more complex and simply scientific solutions considered in isolation may not result in positive outcomes in society.
This is what physicians have known for thousands of years. Doctors have to abide by the ethical principle to“first do no harm” in their medical practice. This Hippocratic ideal is at the core of the preacautionary principle and has been extended to the environmental sciences. This principle which was formalized in the 1992 Rio Climate Change Convention states that “Where there are threats of irreversible damage, lack of full scientific uncertainty should not be used as a reason for postponing interventions”
The precautionary principle essentially means science cannot achieve certainty and yet science still has to be used. If no intervention is used, then it will be more certain that harm will be done. This again is a question medical doctors meet in their practice. The doctors will have to weigh risks. Should a child be vaccinated or not? What are the risks to the child if he/she is vaccinated? What are the risks to other children if the child is not vaccinated?
The question becomes a postnormal one since the risks are estimated for child and society and all sectors must be consulted. In normal science, scientists come up with a theory, apply the theory and it should work and people are not usually consulted. But first some science. Vaccination is based on the germ theory of Louis Pasteur and the immunological theories of Elie Metchnikoff and Paul Ehrlich. Their theories are cannot be reasonably doubted as they are backed by numerous experimental studies. Vaccination works when the human immune system is functioning and for most of us it does. Our patriots like General Antonio Luna, Jose Rizal, Francisco Liongson and Luis Ma Guerrero, all medical doctors or doctors of science did not doubt it (since they all did experiments in immunology) even if they knew the risks. Liongson who later became a senator, authored the law mandating vaccination of all Filipino schoolchildren.
Advances in immunology resulted in many effective vaccines. All have passed stringent clinical trials. In an example I use in my classes, the first extensive one was Dr Jonas Salk’s oral polio vaccine in 1954 in which 400,000 schoolchildren participated in the trial. Two hundred thousand received the vaccine and out of that 57 children contracted the disease. The chance of a vaccinated child contracting polio is very very extremely small. Of course there remains a risk, but a correct decision based on the precautionary principle is to have a child vaccinated. Thus polio has been almost eliminated in the world. This is a “hard scientific fact” but applying the fact is not that simple.
The estimation of risks matter and in the matter of the dengue vaccine, the manufacturer Sanofi has ascertained the “protective” value of the vaccine to a child who has been exposed to the dengue virus but for children younger than nine and were not exposed prior, vaccination may result in more “cases of severe disease could occur following vaccination upon a subsequent dengue infection.”. These are “hard scientific facts” that cannot be reasonably denied. Also in dengue endemic countries, over 90% of the population is seropositive for dengue which means people have the antibodies for the disease and the vaccine may provide more protection.
Using this scientific information, should the DOH have authorized an extensive clinical trial involving 700,000 children? What is the quantified estimated risks of a vaccinated child getting a worse outcome if exposed to a new dengue serotype? Recall that in the Salk vaccine, that bad outcome is extremely small 6.71 x 10^- 16 to be more exact!
The answers are scientific and scientists can provide these. However, the decision to vaccinate children is a policy decision guided and motivated by medical, social and even political outcomes. In postnormal science, the “hard facts” should inform all concerned, the public, parents, the medical scientists, clinical practitioners, the medical associations who draw up medical practice guidelines, politicians, in fact everyone who cares about public health.
Consultations and dialogues will allow the decision made to be science informed and so the public can weigh the benefits and risks. But all must be aware that the decision rests not on just the factualness of science but on the quality of outcomes of applying science. In this case a vaccinated population exposed to a minimal risk as possible.
There is a danger that this issue can be used by interests who deny the scientific fact of vaccines. This could even lead to worse public health outcomes our country cannot afford.
Here we should evaluate the DOH, medical scientists, the medical associations, the clinical practitioners, the child welfare advocates and the presidential administration of Benigno S Aquino III. Was the decision made for political expediency alone?


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