To give an idea, and to offer some data, every year almost 409,000 lives are killed by malaria. Younger children are estimated to account for around 64% of victims. 94% of the total malaria cases (out of 215 million) occur in the area of sub-Saharan Africa (WHO data, “World Malaria Report 2020”).
As is known, this infectious disease is caused by the protist parasites of the genus Plasmodium, which are transmitted to humans by the bite of an infected mosquito (in spite of itself). The effects vary depending on the Plasmodium species involved. The best known and typical symptoms of malaria are chills and fever which tend to recur cyclically: every other day in Plasmodium Vivax and Plasmodium Ovale infections, and every three days in Plasmodium Malariae infections. The cycles caused by Plasmodium Falciparum are more frequent and violent, and in this case the fever tends to be continuous. If the infection reaches the brain, especially in children, it can cause irreversible brain damage, cognitive impairment, coma and death.
It took over forty years of research and experimentation for the British pharmaceutical company GlaxoSmithKline – which in Italy, among other things, is engaged in the field of monoclonal antibodies against Covid – to produce Mosquirix (acronym RTS, S / AS01 ). Mosquirx, this is the baptismal name, is a recombinant protein of the surface protein of P. Falciparum, aided by the surface antigen of the hepatitis B virus, and by liposomes, i.e. lipid particles, containing a Toll-like receptor 4 antagonist (the receptor that activates the immune-inflammatory response).
Mosquirix has been shown, among other things, to induce antibodies to the hepatitis B virus as effectively as a currently licensed hepatitis B vaccine. According to the EMA, the vaccine must be administered above all in the areas most affected by Plasmodium falciparum (Nigeria, Congo, Tanzania, Burkina Faso, Mozambique and Niger) and although it can help to combat hepatitis B it cannot be used with this exclusive purpose.
In the last phase of an experiment conducted in three pilot countries (Ghana, Kenya and Malawi) on about 800,000 children, Mosquirix proved effective in reducing childhood infections, especially in the 12 months following the third injection.
In a larger study involving over 120,000 children from 7 African countries, the number of children who contracted malaria after the first dose was 24% lower among subjects aged 6 to 12 weeks, and 43% for those aged between 5 and 17 months. Mosquirix has thus been seen to provide protection that can save thousands of lives in the age group most at risk of malaria. The effectiveness margin remains low (30%), but it is already a very important and consoling result. The protection offered by the vaccine is short-term: after the third dose it decreases over time. For this reason, a fourth injection is required, to be done with a gap of 18 months from the first three.
If the studies up to 2015 did not seem too comforting, with an efficacy of 50% in the first year and a drop to zero in the fourth, the 2.3 million doses administered in the last trial instead showed an average reduction of 30. % of severe symptoms, making the use of the vaccine decidedly convenient, although still not decisive.
This is a research that GlaxoSmithKline started in the 1980s, and which today, thanks also to the funding of an alliance coordinated by the WHO (composed of Gavi, Vaccine Alliance, Global Fund for the fight against AIDS, tuberculosis and to malaria, Unitaid, Path, Unicef and Gsk) has achieved a decidedly important result, which remains a first step, but it is a great step forward.
