The picture of Tedros Adhanom Ghebreyesus, director of the World Health Organization, will be linked for life to Covid-19. However, since the Ethiopian leader took over the reins of the international organization, progress has also been made in the fight against other diseases. Last Monday, without going any further, announced WHO support for a new malaria vaccineR21/Matrix-M, developed by the University of Oxford (United Kingdom) and produced by the Serum Institute of India, the largest vaccine factory in the world by number of doses.
This is the second malaria vaccine to receive the WHO recommendation, after RTS, S (Mosquirix). “This is a historic moment. The long-awaited malaria vaccine for children is a great advance for science, children’s health and disease control,” Tedros Adhanom himself acknowledged in October 2021, when they took a position for the first time in history in favor of use of the only approved vaccine against malaria.
That discovery gained greater significance since it was also the first vaccine against a parasite that causes disease in humans. And it is that ‘killing’ a parasite is not the same as killing a virus or bacteria: “Developing a vaccine that works and that generates a protective immune response against a virus is technically much simpler than against a parasite,” explains Quique Bassat, ICREA researcher at ISGlobal and director of the Malaria and Neglected Parasitic Diseases program.
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That is why it is considered “an important milestone” that within a period of 24 months the WHO has shown its support for two vaccines that have proven to be safe and effective in preventing a disease that causes half a million deaths a year. Each country will decide which immunization to choose depending on its availability and price (R21/Matrix-M doses will cost between 1.9 and 3.8 euros, according to the WHO). In fact, Ghana had already approved the new vaccine last April, being the first in the world to take this step.
“It has nothing to do with a political decision“, says Bassat in statements to EL ESPAÑOL, “but with a technical difficulty when producing it.” Although it also shows, in his opinion, that malaria does not affect everyone equally: “There has been no bad faith by the WHO, far from it. But perhaps there has been a lack of interest from the north of the world when it comes to worrying about a disease that mainly affects the south.” In 2021, malaria killed 619,000 people in the world, 96% of these deaths They occurred on the African continent.
40 years in development
According to WHO datathere are 89 vaccines in an active situation —that is, some clinical development activity has been registered in the last three years—, involved in a total of 153 clinical trials. Among the candidates, 44 target the parasite (Plasmodium sickles), 41 to the blood phase and nine to the sexual phase or transmission blockage.
In the case of those that have already received the WHO recommendation, there are not many differences: “They are essentially similar vaccines. The antigen around which they are built is very similar,” explains Bassat. The first of them, however, offers a particularity compared to the Oxford one: it has its origin at the end of the decade of the 80s.
“For malaria, which is a perpetual public health emergency, it took 40 years to have a first vaccine. This is something we can complain about because For Covid we have had four vaccines ready in six monthssince the virus was detected,” denounces the Catalan researcher. Currently there are up to 10 vaccines against SARS-CoV-2 that have the recommendation of the advice of the WHO Strategic Advisory Group of Experts on Immunization (SAGE).
Bassat believes that it is logical that there have been less effort and less interest by the pharmaceutical industry of northern countries for a disease that today mainly affects the southern hemisphere. Even so, he prefers to look ahead and not pay so much attention to why it has taken so long: “We must look at the good news, that we already have two vaccines that can begin to be mass produced so that they reach around 25 million children born in malaria-endemic African countries.
“They are imperfect vaccines”
Despite the success achieved with the new injections, these will not become the main way to eradicate malaria, as Bassat points out: “They are imperfect vaccines, which They are not completely effective“. Thus, if there are vaccines that have demonstrated efficacy close to 95% in other pathologies, R21/Matrix-M reduces by 75% symptomatic cases of malaria in the year after the complete vaccination cycle. “It cannot be considered the magic bullet that will solve the malaria problem.”
In their opinion, they will contribute significantly to reducing its impact. “Taking into account above all that the vaccination programs that exist in the world are one of the few health interventions that have very good coverage.” Obviously, he understands that A vaccine plan in Spain is not the same as in Mozambique“.
Bassat hopes that this first generation of vaccines will be the beginning of the development of highly potent malaria vaccines. Until then, mosquito nets will continue to be the tool with the greatest impact to curb malaria cases and deaths. “They are what protect you when you are exposed at night to the bites of the mosquito that transmits the parasite”.
However, it is also “an imperfect tool” because it presents significant logistical difficulties. “In addition, they must be used periodically for it to have an effect.” In this sense, the UN launched an advert in August of this year, highlighting that progress against malaria had been reversed in at least 13 countries, especially since 2015. “That is why the vaccine will have to be added to the measures that already exist. And Although they do not completely resolve the situation, they will contribute to improving it.“, concludes Bassat.
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2023-10-06 00:45:50
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