By 2015, vaccination programs in the Philippines had demonstrated so must success that 93 per cent of the public trusted them. The anti-vaccination movement that had been energised by a fraudulent 1998 paper by Andrew Wakefield alleging links between MMR vaccines had found the Philippines barren ground. Until 2018.
Researchers at the London School of Hygiene & Tropical Medicine, the University of Washington, the Asian Institute of Management, and Imperial College London, found that confidence in vaccines across the board had plummetted to 32 per cent. That drop threatens successful public health programs across the country, leaving local health workers with an uphill climb to persuade their communities that measles vaccines and even de-worming medicines were safe.
As we have been working on this series two significant events have occurred. The Philippine Department of Health has revealed a 21 per cent increase in Dengue infections in the Philippines following the Dengavaxia death claims and suspension of a public vaccination program. It has resulted in 700 children dead, also a year on year significant increase.
At the same time, Dengavaxia is to be approved by the EU, as dengue in emerging in EU countries.
No other country has followed the Philippine claims of Dengvaxia deaths or reacted to the claims.
By the late 18th century vaccination had come a long way, but how did it work?
Over millions of years, the human body has evolved numerous ways of protecting itself against attacks of various sorts. One shield in its arsenal is antibodies. When a virus makes the body sick antibodies are produced that learn to identify and fight the disease. When exposed to attack by that same virus again antibodies destroy it, the body is now immune.
Vaccines against Dengue may be new but vaccination itself is 215 years old in the islands. It may, in fact, be older, but that is just a matter of complete speculation. The history of Smallpox vaccination shows a number of similarities to the present controversy surrounding Dengvaxia.
Smallpox is an ancient scourge. Signs of its characteristic ugly blisters, or pustules, have been found on Egyptian mummies around 4,000 years old. Knowledge of smallpox immunity may be as old as the disease itself.
Deadly, disfiguring and disabling though the disease was, it was known that those who survived it – epidemics in the Philippines in the 1700s could kill a third of those infected – did not get it again. Around 430 BCE smallpox sufferers were being cared for by those who had already survived the disease. Although the mechanism for this was not known at the time techniques were developed in an attempt to induce immunity.
Before 1970 only 9 countries experienced severe Dengue epidemics. It is now endemic in 100 countries including Africa, the Americas, the Eastern Mediterranean, South-East Asia, and the Western Pacific.The America, South-East Asia and Western Pacific regions are the most seriously affected. That includes the Philippines. In 2015, 2.35 million cases of dengue were reported in the Americas alone, of which 10,200 cases were diagnosed as severe dengue causing 1.181 deaths.
Says the World Health Organisation, WHO, “Not only is the number of cases increasing as the disease spreads to new areas, but explosive outbreaks are occurring. The threat of a possible outbreak of dengue fever now exists in Europe as local transmission was reported for the first time in France and Croatia in 2010 and imported cases were detected in 3 other European countries. In 2012, an outbreak of dengue on the Madeira islands of Portugal resulted in over 2 000 cases and imported cases were detected in mainland Portugal and 10 other countries in Europe. Among travellers returning from low- and middle-income countries, dengue is the second most diagnosed cause of fever after malaria.”
In the Philippines, it is the 7th biggest killer of children of children up to four years old and the second leading cause of death in children between 5 and 9, and the sixth leading cause of death among child between the ages of 10 and 14.
Over the past few years, Dengue fever, and severe Dengue have become major public health issues. Its prevalence is increasing. It affects billions of people around the world, many of them in low income and developing countries and there is no cure. Once some has contracted it there is little to be done except treatment of its symptoms and providing plenty of fluids.
It is an economic burden, both at the level of the family with a person affected by Dengue, and at the national level. Not to mention the emotional stress of parents with a child threatened by Dengue.
Prevention is a preferable option, but its success depends on economic, environment and cultural factors.
In many cases of vaccine-preventable diseases there is the principle of ‘herd immunity’ – a certain percentage of the population must be immunised for the vaccine to protect the whole of the population. Measles is an example. However, because of Dengue disease vectors this is not an approach that works.
Let’s take a look at what Dengue is, what is happening in a global context.
I have thought long and hard about covering the Dengvaxia controversy in the Philippines. It is not history, although it is historic. The issue, to my mind is what scientific evidence is there to support the claims that Dengvaxia has killed Filipino children? Are the claims supportable? Does what little evidence available support the claim? What damage is the controversy doing to other vaccination programmes?
What is at stake is the lives of children. If the Philippine government’s Public attorney’s office, PAO, is correct, then there is a serious issue to be addressed, if it is wrong it is putting at risk the lives of hundreds, if not thousands of Filipino children and hazarding the lives of kids in the other 18 countries where Dengvaxia is being used.
I have spoken to clinicians, epidemiologists and public policy experts throughout the SE Asian region. I have asked PAO for its input and should it respond then its comment and clarifications will be included.