• Vaccine Name: PvDBPII/Matrix-M1
• Target Pathogen: Plasmodium spp.
• Target Disease: Malaria
• Type: Subunit vaccine
• Status: Clinical trial
• Host Species for Licensed Use: Human
• Antigen: PvDBPII: region II of P. vivax Duffy-binding protein (Hou et al., 2022)
• PvDBPII gene engineering:
  • Type: Recombinant protein preparation
  • Description: Region II of PvDBP, a 327-amino acid domain. (Hou et al., 2022)
  • Detailed Gene Information: Click Here.
• Adjuvant: Matrix-M vaccine adjuvant
  • Adjuvant name: Matrix-M vaccine adjuvant
  • VO adjuvant ID: VO_0005206
• Immunization Route: Intramuscular injection (i.m.)

Human Response

• Host Strain: healthy adults living in the UK (Minassian et al., 2019)
• Vaccination Protocol: Phase I/IIa, blood-stage trial
  Volunteers received vaccination based on the time they participated in the experiment: group 1 received three doses of the PvDBPII 50ug/Matrix M1 50ug vaccine at 0, 1 and 14 months, and group 2 received three doses of the PvDBPII 50ug/Matrix M1 50ug vaccine at 0, 1 and 2 months. (Hou et al., 2022)
• Immune Response: Humoral: Anti-PvDBPII (SalI) total IgG serum antibody responses peaked around 2 weeks following the final vaccination. PvDBPII/M-M given at 0, 1 and 14 months induced higher response (geometric mean 198 μg/mL, range 153–335).
  Cellular: PvDBPII-specific CD4+ CD45RA− CCR7− effector memory T cells producing IFN-γ were detectable following final vaccinations in a delayed dosing regimen. IFN-γ producing CD8+ effector memory T cells were not detectable. (Hou et al., 2022)
• Side Effects: Mild or moderate cases of warmth, itch, injection site pain, redness, malaise, nausea, fatigue, headache, feverishness, myalgia, arthralgia, and temperature, all resolved within 48 hours. (Hou et al., 2022)
• Challenge Protocol: Blood stage CHMI 2–4 weeks after the third dose of vaccination (Hou et al., 2022)
• Efficacy: All volunteers developed parasitemia, but the PMR and LCP is significant lower in the delayed dosing group compared to unvaccinated controls, due to the delayed dosing (PMR: 3.2-fold growth per 48 hours (range 2.3 to 4.3) compared to 6.8-fold growth per 48 hours [range 4.0 to 11.1], p <0.001), resulted in a 7-day delay in median time to reach malaria diagnosis (15.5 days in controls compared to 22.5 days in delayed dosing group). (Hou et al., 2022)