Children's Health Defense The World Health Organization (WHO), a pair of articles recently published in The BMJ have revealed, is sponsoring an experimental study of a controversial malaria vaccine among African children without obtaining informed consent from parents.
Data from prior clinical trials of the vaccine, manufactured by the British multinational pharmaceutical corporation GlaxoSmithKline (GSK), have shown it to be associated with an increased risk of clinical malaria after four years, a tenfold increased risk of meningitis, an increased risk of cerebral malaria (in which the parasitic organisms block the flow of blood to the brain, causing swelling and potential brain damage), and an increased risk of death that was disproportionately higher for female children.
Concerningly, apart from failing to properly inform parents about the risks or even letting parents know that their children are being experimented upon, the WHO intends to make a decision based on this trial about whether to recommend the vaccine for routine use throughout sub-Saharan Africa after just twenty-four months of study, which is not enough time to determine the vaccine’s effect on mortality.
This is especially concerning in light of scientific research showing that other non-live vaccines—such as the diphtheria, tetanus, and whole-cell pertussis (DTP) vaccine—are associated with an increased rate of childhood mortality. The WHO, however, has dismissed this evidence and continues to recommend the DTP vaccine for routine use in children in developing countries.
The behavior of policymakers at the WHO, while highly alarming, is not at all surprising given the organization’s conflicts of interest, including industry funding and members of its vaccine advisory group having financial ties to pharmaceutical companies.
Waning of Vaccine-Conferred Immunity After Four Years
GSK’s malaria vaccine has long been under development, but while the company and the WHO appear intent on rolling it out across Africa, concerning data from clinical trials has been publicly known for years. In 2013, the results of four years of trial follow-up in Kilifi, Kenya, were published in the New England Journal of Medicine (NEJM). The data showed that, while apparently effective at preventing clinical malaria initially, after four years, the vaccine had negative effectiveness, meaning that children who received the vaccine had an increased risk of symptomatic parasitic infection.
That study involved randomly vaccinating Kenyan children aged five to seventeen months with either the experimental malaria vaccine or a rabies vaccine. Importantly, the clinical endpoint of the trial was malaria incidence, not mortality. Even so, the data showed a vaccine efficacy of only 43.6 percent in the first year, which fell to –0.4 percent in the fourth year. While the negative efficacy was not statistically significant, the study authors acknowledged that the results show that the immunity conferred by the vaccine wanes after just a few years.
While the vaccine was judged to be initially effective in stimulating the production of antibodies against the sporozoite stage of the parasite, which is the form typically introduced into the blood of human hosts by mosquitos, the researchers acknowledged that a high level of anti-sporozoite antibodies doesn’t necessarily equate to immunity and that the immunity conferred by the vaccine differs from that acquired naturally through infection.
While anti-sporozoite antibodies “may mediate protection and were associated with a reduced risk of clinical malaria”, a waning of antibody titers was observed over time in children who received the malaria vaccine.
Additionally, they suggested that because children receiving the malaria vaccine had reduced exposure to later blood-stage parasites, they would have had “delayed acquisition of natural immunity”, which could also help explain the negative efficacy by the fourth year. In other words, the rapidly waning vaccine-conferred immunity was achieved at an opportunity cost of a delayed and superior natural immunity.[1]
The Importance of Natural Immunity and Scientific Uncertainty about How It’s Achieved
The uncertainties about how immunity to malarial parasites is achieved were elucidated in an editorial in the journal Parasitology in 2016. Noting that “individuals living in endemic areas naturally acquire immunity to symptomatic malaria”, its authors pointed out that “immune correlates of protection” were not yet understood by scientists. While certain “antigen-specific immune responses associated with protection against malaria infection and disease” have been identified, scientific reviews “highlight the complexity of immunity to malaria and that even after 100 years we still have much to learn.”