• Vaccine Name: Pb(PfCS@UIS4)
• Target Pathogen: Plasmodium spp.
• Target Disease: Malaria
• Type: Live, attenuated vaccine
• Status: Clinical trial
• Host Species for Licensed Use: Human
• Antigen: Pb(PfCS@UIS4): genetically modified parasite: P. falciparum circumsporozoite (CS)- protein gene integrated in the P. berghei parasite. (Reuling et al., 2020)
• CS from P. falciparum gene engineering:
  • Type: Genetic modification
  • Description: PfCS expressed by P. berghei (Reuling et al., 2020)
  • Detailed Gene Information: Click Here.
• Immunization Route: infectious mosquito bites

Human Response

• Vaccination Protocol: Non-randomized phase I/IIa study.
  Volunteers in the experiment groups were first exposed to 1) 5, 2) 25, or 3) 75 Pb(PfCS@UIS4)-infected mosquitoes for first dose of vaccination, and were then exposed to ~75 Pb(PfCS@UIS4)-infected mosquitoes on week 4, 8, and 16 for the second, third, and fourth doses of vaccination. Group 3 were challenged by 5 Pf-infected mosquitoes together with the control group that did not receive vaccination. (Reuling et al., 2020)
• Side Effects: Mild or moderate headache, nausea, and malaise. (Reuling et al., 2020)
• Challenge Protocol: CHMI: volunteers were exposed to 5 NF54 Pf-infected mosquitoes 3 weeks after the last dose of vaccination (Reuling et al., 2020)
• Efficacy: Sterile protection against an NF54 P. falciparum challenge was not observed, but there was a significant delay in time to parasitemia in PbVac-immunized subjects (9.9 ± 2.0 days) compared to controls (7.7 ± 1.6 days) (P=0.026) There was also a significantly 12.8-fold lower parasite peak density on the day of first positive PCR in immunized volunteers compared to the control group (P = 0.04) Collectively, this corresponds to an estimated 95% average reduction in parasite liver load. (Reuling et al., 2020)