The development of RTS,S/AS01 vaccine is expected to reduce the global burden of malaria. This recombinant fusion based antigen consist of four amino acids. They are found in the surface of sporozoite P.falciparum arranged in a sequential manner.
The term RTS suggest this sequential arrangement – “repeat T epitopes” and S for the antigen S derived from hepB surface antigen. The term AS01 denotes the proprietary adjuvants.
Clinical trail results
The phase III, clinical trials of the vaccine produced a satisfactory result in infants aging 5 – 17 months and had established a partial protection. It also suggested the benefit of an 18 month booster. The three dose schedule + a booster (0, 1, 2, and 20) schedule established a 36 percent efficacy.
Another trail found out that the same vaccine schedule established a decline of vaccine efficacy to zero between the four years of vaccine administration.
The vaccine established a better protection profile against a parasite that has a similar protein allele found in the vaccine.
In 2015, SAGE experts recommended to avoid mass vaccination with RTS,S/AS01 and instead consider a series of pilot studies.