Safety, Immunogenicity, and Efficacy of Prime-Boost Immunization with Recombinant Poxvirus FP9 and Modified Vaccinia Virus Ankara Encoding the Full-Length Plasmodium falciparum Circumsporozoite Protein
Walther M., Thompson FM., Dunachie S., Keating S., Todryk S., Berthoud T., Andrews L., Andersen RF., Moore A., Gilbert SC., Poulton I., Dubovsky F., Tierney E., Correa S., Huntcooke A., Butcher G., Williams J., Sinden RE., Hill AVS.
ABSTRACT Heterologous prime-boost immunization with DNA and various recombinant poxviruses encoding malaria antigens is capable of inducing strong cell-mediated immune responses and partial protection in human sporozoite challenges. Here we report a series of trials assessing recombinant fowlpox virus and modified vaccinia virus Ankara encoding the Plasmodium falciparum circumsporozoite protein in various prime-boost combinations, doses, and application routes. For the first time, these vaccines were administered intramuscularly and at doses of up to 5 × 10 8 PFU. Vaccines containing this antigen proved safe and induced modest immune responses but showed no evidence of efficacy in a sporozoite challenge.