A clinical trial of prime-boost immunisation with the candidate malaria vaccines RTS,S/AS02A and MVA-CS.
Dunachie SJ., Walther M., Vuola JM., Webster DP., Keating SM., Berthoud T., Andrews L., Bejon P., Poulton I., Butcher G., Watkins K., Sinden RE., Leach A., Moris P., Tornieporth N., Schneider J., Dubovsky F., Tierney E., Williams J., Heppner DG., Gilbert SC., Cohen J., Hill AVS.
Heterologous prime-boost immunisation with RTS,S/AS02A and the poxvirus MVA-CS was evaluated in 18 healthy malaria-naïve subjects in Oxford. Both priming with RTS,S and boosting MVA-CS, and the reverse, were found to be safe and well tolerated. T cell responses as measured by IFN-gamma ex vivo ELISPOT were induced, but the responses were low to moderate in both groups, with heterologous boosting yielding only small increments in T cell immunogenicity and no increased antibody response. Protection against 3D7 Plasmodium falciparum sporozoite challenge 4 weeks after the final vaccination was equal for both regimens at 33% (95% C.I. 4.3-77.7%), with one subject remaining fully protected on rechallenge at 5 months.