The selective pressure induced by malaria vaccines onPlasmodium falciparum

Abstract

Antigens of Plasmodium falciparum targeted by most current and future vaccines are generally not conserved. There are limited studies estimating the risk of parasite selection with vaccines. We adapted an individual-based model of malaria to assess which conditions favour genotypes having some degree of vaccine resistance and estimate the impact of resistance spread on vaccine effectiveness. Even parasite genotypes with low degrees of vaccine resistance are likely to spread relatively quickly if vaccines are implemented in children and even faster in a broader population. However, only highly resistant genotypes could strongly reduce vaccine effectiveness. These results highlight that it is essential to understand the degree to which genotypes exhibit reduced sensitivity to vaccines and monitor genotype frequency and vaccine effectiveness along with vaccine deployment. If some genotypes exhibit reduced efficacy to vaccines, our results further suggest that polyvalent or combination vaccines should be considered to limit resistance spread.