Malaria is one of the few mass-killer diseases still holding its fort against vaccines. It is because the culprits, parasites such as Plasmodium Falciparum, are more complex than viruses. But the story is changing. This week, The Lancet Infectious Diseases published an article summarising the study results of the R21/Matrix-M vaccine, which combines Oxford’s R21 and Novavax’s Matrix-M.
It was a randomised control trial involving around 400 children aged 5 – 17 months from Nanoro, Burkina Faso. The participants were divided into three groups to receive either a 25-microgram, 50-microgram malaria vaccine or a placebo. Note that 25 and 50 represent the doses of Matrix-M. R21 remained 5 micrograms in both cases. They also received a booster dose after 12 months. Note that the jabs were given before the malaria season.
Following was one set of results:
| Group | Primary Case clinical malaria | Total number |
| 5 μg R21 25 μg Matrix-M | 67 | 132 |
| 5 μg R21 50 μg Matrix-M | 54 | 137 |
| Control rabies vaccine | 121 | 140 |
The numbers in the tables are the cumulative incident values collected over a year (from 14 days since the booster to 12 months). The Hazard Ratio (risk ratio of the intervention group to the control group) is estimated by regression of the survivorship plot using the Cox proportional hazards model. The efficacy = 1 – HR is estimated to be 71% for the low-dose group (group 1) and 80% for the high-dose group(group 2).
Efficacy and immunogenicity of R21/Matrix-M vaccine: The Lancet Infectious Diseases
Randomised Controlled Trials: BMJ
Types of malaria parasites: Stanford medicine
