Extended follow-up of children in a phase2b trial of the GMZ2 malaria vaccine
Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
The GMZ2/alum candidate malaria vaccine had an efficacy of 14% (95% confidence interval
[CI]: 3.6%, 23%) against clinical malaria over 6 months of follow-up in a phase2b multicentre trial in chil dren 1–5 years of age. Here we report the extended follow up of safety and efficacy over 2 years.
Methods: A total of 1849 (GMZ2 = 926, rabies = 923) children aged 12–60 months were randomized to
receive intramuscularly, either 3 doses of 100 lg GMZ2/alum or 3 doses of rabies vaccine as control
28 days apart. The children were followed-up for 24 months for clinical malaria episodes and adverse
events. The primary endpoint was documented fever with parasitaemia of at least 5000/lL.
Results: There were 2,062 malaria episodes in the GMZ2/alum group and 2,115 in the rabies vaccine
group in the intention-to-treat analysis, vaccine efficacy (VE) of 6.5% (95%: CI 1.6%, 14.0%). In children
aged 1–2 years at enrolment, VE was 3.6% (95 %CI: 9.1%, 14.8%) in the first year and 4.1% (95 %CI:
18.7%, 87%) in the second year. In children aged 3–5 years at enrolment VE was 19.9% (95 %CI: 7.7%,
30.4%) in the first year and 6.3% (95 %CI: 10.2%, 20.3%) in the second year (interaction by year,
P = 0.025, and by age group, P = 0.085). A total of 187 (GMZ2 = 91, rabies = 96) serious adverse events
were recorded in 167 individuals over the entire period of the study. There were no GMZ2 vaccine related
serious adverse events.
Conclusions: GMZ2/alum was well tolerated. Follow-up over 2 years confirmed a low level of vaccine
efficacy with slightly higher efficacy in older children, which suggests GMZ2 may act in concert with naturally acquired immunity.
Description
Research Article
Keywords
GMZ2, Malaria, Vaccine, Plasmodium falciparum, Efficacy, Children, Africa