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Proposal 1016

Title of the Proposed Research

Statistical methods for estimating the duration of protection of malaria vaccines: secondary analysis of data from the RTSS/AS02A trial in Mozambique.

Lead Researcher

Paul Milligan


London School of Hygiene and Tropical Medicine
London, UK

Funding Source


Potential Conflicts of Interest


Data Sharing Agreement Date

21 October 2014

Lay Summary

Malaria vaccines are unlikely to give long-lasting protection, booster doses will be required to maintain the high levels of antibodies and cellular responses that are required to maintain a moderate degree of protection. Unfortunately there is no immunological marker that can reliably be used to determine if a child is protected, the duration of protection and hence the interval between booster doses must therefore be determined from analysis of the incidence of malaria in vaccinated and unvaccinated children, from clinical trial cohorts, or in phase 4 studies in areas where the vaccine has been introduced, using case control studies, but there is no established methodology for these analyses and the methods commonly used have known biases. The purpose of this project is to develop statistical methods that can be used to estimate the duration of protection. Data from the phase 2b trial of the RTSS/AS02A vaccine in Mozambique will be used as the motivating example, to develop and evaluate the methods, and to demonstrate the use of the methods. In this trial children were randomized to receive malaria vaccine or rabies vaccine and kept under malaria surveillance until month 42, published analyses indicate efficacy may have waned gradually during this period, the long period of follow-up, large sample size, and evidence of vaccine protection that seems to wane over time, makes this a very suitable dataset for this purpose. The results of this work will be published in peer-reviewed journals and if the methods are successful they will be made available to malaria researchers via software modules in Stata.

Study Data Provided

Study 257049/026: A study to evaluate the safety, immunogenicity and efficacy of GlaxoSmithKline Biologicals’ candidate malaria vaccine RTS,S/AS02A, administered intramuscularly according to a 0, 1 and 2 month vaccination schedule in toddlers and children aged 1 to 4 years in a malaria-endemic region of Mozambique.
Study 104297: An open study for a 2-year period to confirm the safety and immunogenicity of the candidate malaria vaccine RTS,S/AS02A in Mozambican children aged 1 to 4 years at the time of first vaccine dose.

Statistical Analysis Plan

This will be added after the research is published.

Publication Citation