Pfs25-EPA + Alhydrogel

Pfs25-EPA + Alhydrogel is a malaria transmission-blocking vaccine candidate designed to prevent the spread of *Plasmodium falciparum* by targeting the parasite's sexual stage development in mosquitoes. The vaccine consists of recombinant Pfs25 protein (expressed in *Pichia pastoris*) chemically conjugated to recombinant ExoProtein A (EPA) from *Pseudomonas aeruginosa* (expressed in *E. coli*), and formulated with Alhydrogel, an aluminum hydroxide adjuvant. The conjugation to EPA enhances the immunogenicity of the otherwise poorly immunogenic Pfs25 antigen. Upon administration, it induces antibodies against Pfs25 that can block parasite development within mosquitoes after a blood meal from vaccinated individuals, thereby interrupting malaria transmission[1][2][3]. Clinical studies have shown that while this formulation is well tolerated and immunogenic, antibody titers decline rapidly and actual transmission-blocking activity was not robust or long-lasting[1][2].