Vaccine can protect some adults from malaria long-term

In other words, after 4 immunizations with PfSPZ at 2.7×10⁵ IV, 6 of 11 (55%) vaccinated subjects remained without parasitemia following CHMI at 21 weeks after immunization.

Five of the subjects without parasitemia underwent CHMI again at 59 weeks, and none developed parasitemia.

Based on these results, the researchers hypothesize that further increasing the dose of PfSPZ will increase the magnitude and durability of efficacy. They said ongoing studies using 4.5×10⁵ to 2.7×10⁶ PfSPZ per dose are assessing this for homologous CHMI, heterologous CHMI, and natural exposure in all age groups.