A phase I safety and immunogenicity trial with the candidate malaria vaccine RTS,S/SBAS2 in semi-immune adults in The Gambia

• Published in: The American journal of tropical medicine and hygiene Vol. 61; no. 6; pp. 865 - 868
• Main Authors: Doherty, JF, Pinder, M, Tornieporth, N, Carton, C, Vigneron, L, Milligan, P, Ballou, WR, Holland, CA, Kester, KE, Voss, G, Momin, P, Greenwood, BM, McAdam, KP, Cohen, J
• Format: Journal Article
• Language: English
• Published: Lawrence, KS ASTMH 01.12.1999; Allen Press
• Subjects: Adolescent; Adult; Animals; Antibodies, Protozoan - blood; Antigens, Protozoan - immunology; Biological and medical sciences; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Gambia; Hepatitis B Antibodies - blood; Hepatitis B Surface Antigens - blood; Hepatitis B Surface Antigens - immunology; Human protozoal diseases; Humans; Infectious diseases; Malaria; Malaria Vaccines - administration & dosage; Malaria Vaccines - adverse effects; Malaria Vaccines - immunology; Malaria, Falciparum - blood; Malaria, Falciparum - prevention & control; Male; Medical sciences; Middle Aged; Parasitic diseases; Plasmodium falciparum - immunology; Plasmodium falciparum - isolation & purification; Protozoal diseases; Protozoan Proteins - immunology; Reference Values; Tropical medicine; Vaccines, Synthetic - adverse effects; Vaccines, Synthetic - immunology; Gambia; Africa; Human; Protozoa; Apicomplexa; Protozoal disease; Malaria; Tolerance; Vaccine; Parasitosis; Cell surface; Protein; Infection; Plasmodium falciparum; Immunogenicity; Clinical trial
• ISSN: 0002-9637; 1476-1645
• DOI: 10.4269/ajtmh.1999.61.865

RTS,S is a novel pre-erythrocytic malaria vaccine based on the circumsporozoite surface protein (CSP) of Plasmodium falciparum linked to hepatitis B surface antigen (HBs) and combined with a novel adjuvant system (SBAS2). We have conducted a Phase I trial with three doses of this vaccine given at 0, 1, and 6 months to 20 semi-immune, adult, male volunteers in The Gambia to assess its safety and immunogenicity. Eighteen of the 20 volunteers completed the study. There were no clinically significant local or systemic adverse events following each vaccination. Hematologic and biochemical indices before and two weeks after each vaccination showed no evidence of toxicity. Antibody titers to both CSP and HBs showed a significant increase after vaccination; these were the largest after the third dose. We conclude that the RTS,S/SBAS2 vaccine induces no significant toxicity in this semi-immune population and produces significant increases in antibody titers to CSP.