The first vaccine against malaria: an imperfect yet giant leap for humanity.
Written by Gerard Carot-Sans
Winston Churchill used to say that success consists of going from failure to failure without loss of enthusiasm. One of the most stoic examples of this aphorism is the fight against malaria. This infection, transmitted through the bite of the mosquito Anopheles sp., has for decades been responsible for the deaths of between 400,000 and 700,000 people each year in the world, mostly children concentrated in sub-Saharan Africa.
The first indications that the disease could be prevented by a vaccine appeared in the late 1970s. But it was not until 2015 that the accumulated evidence on one of the vaccine candidates had a favorable report from the European Medicines Agency, which led to many pilot studies aimed at delving into its effectiveness. The vaccine (called RTS,S/AS01) is based on a subunit of the protozoon that causes the most severe form of malaria (Plasmodium falciparum) and acts before the microorganism enters the blood cells. This was just one out of dozens of candidates, on which more than 180 clinical trials have been conducted in the past 20 years. Yet, it marked a turning point in the fight against the disease.
On October 6, 2021, the World Health Organization (WHO) reached an outstanding milestone in the history of malaria with the publication of a recommendation ―for the first time in history― for widespread use of the RTS,S/AS01 vaccine in children in sub-Saharan Africa and other parts of the world where the most severe type of malaria has a notable incidence. The decision has been based on pilot studies, which have allowed 2.3 million doses to be administered and monitored in three African countries. The accumulated information has led to the conclusion that the vaccine is safe and can reduce infant mortality by 30%. But when it comes to public health in disadvantaged countries, the results on efficacy and safety are not enough to carry out mass vaccination campaigns, and other aspects that may seem irrelevant but become key in implementing public health solutions need to be evaluated. In this regard, the WHO has also based its decision on other key findings, including the successful distribution of the vaccine (even in times of pandemic), the equity in reaching all population groups, and no evidence that its administration has discouraged the use of other critical preventative measures, such as bed nets.
After the COVID-19 pandemic, we have all become semi-experts in immunization-related issues; hence, we know that 30% effectiveness is not the end of the road towards eradicating - or even control - an infectious disease. However, this percentage involves saving the lives of millions of children each year around the world. Our collective worldview is often seduced by the romantic idea that medical science moves forward on the basis of “eureka!” cries that change the course of history. But the reality is much more prosaic, and progress is the result of the many failures Churchill mentioned and of their addition into the cluster of partial conquests that, like the WHO recommendation on the RTS,S/AS01 vaccine, do not lead us to the end of the road, but bring us closer to it. Maintaining enthusiasm is the key to any type of success, either big or small.