Plasmodium and RBCThe point of a vaccine trial is to test whether the vaccine works.  If you get an answer to that question, the trial is a success.  The answer may be “No”, in which case the vaccine is a failure, but the trial would still be a success.  (The STEP HIV vaccine trial was therefore a success, though the vaccine was a failure.)

Malaria vaccines have been desperately needed forever, and in the past year there have been a few clinical trials. 1  An encouraging, though unspectacular, trial was reported last year, where the vaccine offered modest protection in children. 2

The most successful vaccines seem to be T-cell based, rather than antibody-based, and the latest report, of a Phase II trial in Kenya,3 drives another nail in the antibody/malaria coffin:

The FMP1/AS02 vaccine did not protect children living in Kombewa against first episodes of P. falciparum malaria; it did not reduce the overall incidences of clinical malaria episodes or of malaria infections, and did not reduce parasite densities … Because of the clearly demonstrated overall lack of efficacy in this trial, FMP1/AS02 is no longer a promising candidate for further development as a monovalent malaria vaccine. … We therefore propose that future MSP-142 vaccine development efforts should focus on other antigen constructs and formulations. 3

For more reading about immunity to malaria:

  1. I don’t actually know much about the history of malaria vaccines, as far as trials go, so I don’t know how unusual it is to have clinical trials.  People have been working on malaria vaccines for decades, but none have worked very well.[]
  2. Abdulla, S., Oberholzer, R., Juma, O., Kubhoja, S., Machera, F., Membi, C., Omari, S., Urassa, A., Mshinda, H., Jumanne, A., Salim, N., Shomari, M., Aebi, T., Schellenberg, D. M., Carter, T., Villafana, T., Demoitie, M. A., Dubois, M. C., Leach, A., Lievens, M., Vekemans, J., Cohen, J., Ballou, W. R., and Tanner, M. (2008). Safety and immunogenicity of RTS,S/AS02D malaria vaccine in infants. N. Engl. J. Med. 359, 2533-2544. doi:10.1056/NEJMoa0807773

    Bejon, P., Lusingu, J., Olotu, A., Leach, A., Lievens, M., Vekemans, J., Mshamu, S., Lang, T., Gould, J., Dubois, M. C., Demoitie, M. A., Stallaert, J. F., Vansadia, P., Carter, T., Njuguna, P., Awuondo, K. O., Malabeja, A., Abdul, O., Gesase, S., Mturi, N., Drakeley, C. J., Savarese, B., Villafana, T., Ballou, W. R., Cohen, J., Riley, E. M., Lemnge, M. M., Marsh, K., and von Seidlein, L. (2008). Efficacy of RTS,S/AS01E vaccine against malaria in children 5 to 17 months of age. N. Engl. J. Med. 359, 2521-2532. doi:10.1056/NEJMoa0807381[]

  3. Ogutu, B., Apollo, O., McKinney, D., Okoth, W., Siangla, J., Dubovsky, F., Tucker, K., Waitumbi, J., Diggs, C., Wittes, J., Malkin, E., Leach, A., Soisson, L., Milman, J., Otieno, L., Holland, C., Polhemus, M., Remich, S., Ockenhouse, C., Cohen, J., Ballou, W., Martin, S., Angov, E., Stewart, V., Lyon, J., Heppner, D., Withers, M., & , . (2009). Blood Stage Malaria Vaccine Eliciting High Antigen-Specific Antibody Concentrations Confers No Protection to Young Children in Western Kenya PLoS ONE, 4 (3) DOI: 10.1371/journal.pone.0004708[][]