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Efficacy model for mosquito stage transmission blocking vaccines for malaria

Published online by Cambridge University Press:  07 February 2008

A. SAUL*
Affiliation:
Laboratory of Malaria and Vector Research, NIAID, and Epidemiology and Population Studies, Fogarty International Center, NIH, 12735 Twinbrook Parkway, Rockville MD 20852USA
*
Corresponding Author: Dr Allan Saul, Novartis Vaccines Institute for Global Health S.r.l. (NVGH), Via Fiorentina 1, 53100 Siena, Italy. Tel: +39 0577 245129. Email: Allan.Saul@novartis.com

Summary

Vaccines that target antigens found on the mosquito stages of Plasmodium falciparum and Plasmodium vivax parasites are under development as transmission blocking vaccines. Antisera from vaccinated animals and humans are able to block oocyst development in artificially fed mosquitoes but it is not clear from these data what level of antibody response would be required for a useful vaccine in a field setting. This paper describes a mathematical model that takes into account the relationship between antibody levels and blocking of oocyst levels in artificial feeds, the distribution of antibody responses seen in human populations and the distribution of oocyst densities in infected mosquitoes in the field to calculate the levels of antibody in the host population that would be required to achieve a level of herd immunity in a vaccinated human population that would give an operationally useful level of transmission blocking. The model predicts that current formulations of Pfs25 are likely to achieve useful reductions in transmission when tested in human field trials.

Type
Research Article
Copyright
Copyright © 2008 Cambridge University Press

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