Data for: A Phase 1b, open-label, age de-escalation, dose-escalation study to evaluate the safety and immunogenicity of different doses of a candidate malaria vaccine; adjuvanted R21(R21/MM) in adults, young children and infants in Kilifi, Kenya

In the era of anti-malaria drug resistance and resistance to insecticide treated bed nets, there is an urgent need for a highly efficacious vaccine. We evaluated a candidate malaria vaccine incorporating the antigen R21 (part of the P. falciparum circumsporozoite malaria antigen co-expressed with hepatitis B antigen plus an adjuvant to boost the immune responses (Matrix-M). R21c/Matrix-M showed promising safety and immunogenicity data in preclinical and early phase trials in Oxford. We conducted an open label, age de-escalation, dose escalation study in 20 healthy adults (18-45 years), 20 young children aged 1-5 years and 51 infants aged 5- <12 months. Each participant was screened to ensure they were in good health based on clinical assessment and laboratory results. Participants had a blood test to ensure suitability prior to vaccination. For each participant, there was a total of 31 visits to the clinic and at home, 15 of which were associated with blood sampling (38 visits for those in the booster phase). Participants recieved 3 vaccinations 4 weeks apart. Blood tests and clinical assessments were conducted to screen out participants with health conditions that may have impacted participants or study outcomes. Bloods were taken at screening and a day prior to enrolment. Blood were also taken prior to each vaccination and on days 2 and 7 post vaccination at the clinic for the primary series ( 3 doses). Home visits were conducted on days 1, 3, 4, 5, and 6 to identify solicited adverse events. Bloods for immunology were taken prior to vaccination, and throughout the study to assess the immune response to R21/Matrix-M. In addition, we invited participants to receive a booster vaccine at 9-25 months after receipt of the 3rd vaccine of R21/Matrix-M and took bloods in clinic 28 days after boosting with field workers supporting participants or their parents/guardians to do this over the phone. During the booster vaccination visit (4th dose_, the participants/Parents/guardians were guided through the measurement of body temperature, assessment of the vaccination site (for redness, swelling and erythema) and documentation of the results on the diary card. They were then issued with a thermometer, vaccination ruler, a copy of the diary card and a pen to facilitate the completion of the remote safety assessments.