Vaccinating with the genome: a Sisyphean task?

Human trials of subunit vaccines against the asexual blood stage of malaria are yielding disappointing results, supporting the premise that a single recombinant protein will not be particularly efficacious and that additional proteins must be added. The genome sequence of Plasmodium falciparum offers a large number of additional candidates, but which should be chosen? Various criteria have been suggested to rank the additional candidates, but in the absence of even a partially effective asexual-stage vaccine, the criteria remain unvalidated. These issues are discussed here, together with some suggestions as to how the development of an asexual-stage vaccine could be progressed.