The scientific community has pursued a vaccine against malaria for more than 100 years. It has been a search that has involved millions of euros and millions of hours of work by scientists and epidemiologists around the world, but it is already a reality: for the first time, there is one that has won the recommendation of the World Health Organization ( WHO) to be administered on a large scale and therefore can be added – not replaced – to the basic package of preventive and diagnostic measures. It is called RTS, S / AS01 from the pharmaceutical company GlaxoSmithKline, Mosquirix by its commercial name, and this Wednesday it has made History.
“I longed for the day when we would have an effective vaccine against this ancient and terrible disease. Today is that day: a historic day. The long-awaited vaccine against malaria for children is a great advance for science, children’s health and the control of the disease, ”said the Director-General of the WHO, Dr. Tedros Adhanom Ghebreyesus at a press conference this Wednesday. “Its use, in addition to existing prevention tools, could save tens of thousands of lives of the youngest each year.”
The immunization recommended by the WHO today acts against the parasite Plasmodium falciparum, transmitted to humans through the bite of female Anopheles mosquitoes, the deadliest in the world and the most prevalent in sub-Saharan Africa. In 2019 There were 409,000 deaths from malaria, 94% of them on this continent, where children are the main victims: more than 260,000 Africans under the age of five die each year from this parasitic disease that infects some 200 million people annually.
“For centuries, malaria has stalked sub-Saharan Africa, causing immense personal suffering,” said Dr. Matshidiso Moeti, WHO Regional Director for Africa. “Today’s recommendation offers a ray of hope for the continent, which bears the greatest burden of the disease,” he added. The position of the WHO, from now on, will be that, in the context of the comprehensive control of this disease, the RTS, S vaccine be used for the prevention of malaria caused by P. falciparum in children living in regions with moderate to high transmission. This should be administered in four doses in children from five months of age.
“This is a vaccine that has developed in Africa, for African children and with African scientists. This field of research is plagued with unsuccessful efforts, and now we have one that has demonstrated its ability to prevent diseases and deaths, ”said Dr. Kate O’Brien, director of the WHO Immunization department, on Monday. in a virtual briefing. Additionally, Pedro Alonso, director of the World Malaria Program of the same organization, highlighted the extraordinary of this finding: “We do not have vaccines against filariasis, or onchocerciasis, or Guinea worms or any protozoan because, from the point of view of Biologically, they are incredibly complex. From a scientific perspective, this is a breakthrough ”.
After three decades of research on this vaccine, after proving safe and effective in clinical trials, and after positive evaluation in 2015 of the European Medicines Agency, WHO sponsored a pilot program to supply it in selected areas of Kenya, Ghana and Malawi. This began in 2019 with a campaign led by the ministries of Health of each country. “It was they who raised their hands to say: ‘We would like to be one of the countries that puts the introduction of this product to the test.’ That really expresses the strong desire for an additional prevention tool, ”O’Brien said.
Financed with 60 million euros by the World Vaccination Alliance Gavi, the Global Fund to Fight AIDS, Tuberculosis and Malaria; and Unitaid, the campaign began with the objective of evaluating different pending issues: the feasibility of administering the four recommended doses, its role in reducing infant deaths, and its safety in the context of routine use. “There were some signs that were a bit puzzling in the phase three clinical trial, and as a precaution, it was important to resolve them, although they were thought to be identified as serendipitous findings,” O’Brien said, because in the larger trial those children who received the RTS, S had 10 times the risk of meningitis than those who received only a control dose. “Through a very careful review it has been shown that these events were not related to its administration,” said the doctor.
Two years later, the results of this pilot program have been assessed by WHO’s main advisory bodies on this matter: the Strategic Advisory Group of Experts on Immunization (SAGE) and the Malaria Policy Advisory Group (MPAG). They have concluded that the results are positive enough to recommend large-scale use of the vaccine. In this time, more than 2.3 million vials have been supplied through the routine immunization programs of each country in more than 800,000 children who have received at least one dose.
Data collected over the past two years demonstrate that RTS, S is safe, significantly reduces severe, life-threatening forms of the disease, and also that it can be administered effectively in real-life childhood vaccination settings, even in times pandemic, as has been demonstrated since the beginning of 2020, with the covid-19 involved.
Given its partial effectiveness, of 36% in children after five months of life, this immunization is not intended as a single remedy, but as a complementary tool to the existing ones that will help reduce infant mortality. “Such a reduction can translate into tens of thousands of lives saved each year,” said Dr. Mary Hamel, leader of the Malaria Vaccine Implementation Program.
A 36% reduction in mortality can translate into tens of thousands of lives saved each year
Dr Mary Hamel, leader of the WHO Malaria Vaccine Implementation Program
Likewise, the WHO has highlighted that this STR, S increases equity in access to preventive measures, since data from the pilot program show that at this time more than two-thirds of children in the three countries who do not sleep under mosquito nets – one of the most effective tools – yes they have benefited from immunization. Specifically, more than 90% of the children did enjoy at least one prevention tool. The WHO has also not found a negative impact on the interaction with other childhood vaccines.
Following this recommendation, what will happen over the next six months is that a search for financial partners will begin as interested countries begin planning how to introduce this tool into their programs. “Nothing dramatic will come to African children in the next six months, but it is a time to make critical decisions that will allow this to happen in the not too distant future,” Alonso suggested. In a joint press release, the Global Fund, Unitaid and Gavi, have celebrated this news and announced that they will consider how to finance a new vaccination program.
Fresh air for a stagnant fight
The fight against malaria during the first part of the 21st century has seen a golden age thanks to the development and implementation of some of the key prevention tools, such as mosquito nets, artemisinin combination treatments, rapid diagnostic tests and the inclusion of the fight against this pathology as one of the Sustainable Development Goals. The creation of the Global Fund and other bilateral agencies also made it possible to have sufficient financial resources. All this has managed to prevent more than seven million deaths and more than 1.5 billion cases.
However, in the last five years, progress has stalled. On numerous occasions, the WHO has warned that with the tools and financial resources available, no further progress could be made. In this context, the approval of this body becomes a historic resolution. “It is an extraordinarily exciting moment,” said Alonso.
Innovations on the way
RTS, S is the first vaccine to achieve the WHO recommendation, but there are others. Last May, the University of Oxford announced that its proposal has shown 77% effectiveness in the preliminary results of its clinical trial, of which phase 3 will begin to continue exploring its capabilities. Also this year, the German laboratory BioNTech announced the beginning of clinical trials of a “safe and very effective” immunization with messenger RNA by the end of 2022. And in the United States, a scientific team has infected 56 volunteers and has verified that subsequent treatment with a drug induces up to 100% protection against the microorganism. “This cannot be the final one. It is a really important one, but we hope that it will demonstrate that vaccines against malaria can be developed and stimulate the search after that complements this or that, hopefully, they go further ”, Dr. Alonso has concluded hopefully.
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