Malaria vaccine trials in a wormy world

The promising malaria vaccine candidates that have been tested in the field have, so far, yielded disappointing and, at times, conflicting results. Considerable efforts are being made to isolate new immunogenic molecules. However, the fact that most populations in malaria endemic areas are also infected by helminths appears to be overlooked. Helminth-related hyporesponsiveness to tetanus or cholera vaccines, and the interactions between malaria parasites and helminths, raise the possibility that a potent malaria vaccine will not be identified in helminth-infected populations, thus necessitating a change in vaccine trial design.