Technical consultation on the malaria rebound phenomenon
On 22–23 March 2022, a WHO technical consultation was convened by the Global Malaria Programme to discuss the malaria rebound phenomenon. The aims of the technical consultation were to:
1)Define what is meant by the rebound phenomenon and understand its determinants.
2)Understand the potential public health significance of the rebound phenomenon.
3)Clarify expectations (e.g. study design, duration of follow-up) for evaluation of the rebound phenomenon during product development.
Experts reviewed key issues with respect to the definitions of rebound and related terms. A review of the evidence from malaria rebound evaluations was discussed to inform understanding of the determinants of the extent of rebound, and the pros and cons of different study designs and analytical approaches. The aim of this discussion was to agree on good practices and a consistent approach to rebound evaluations and analyses across studies. The experts concluded with a discussion of the public health relevance of rebound, including implications for the evaluation of rebound for current and future interventions, approaches to the management of rebound within the public health system, and implications of rebound evaluations for the timing of policy recommendations.
The objectives of the technical consultation are listed below:
- Review existing evaluations of the rebound phenomenon and draw attention to differences in definition, degree and duration of protection, and the approaches to measuring and analysing the phenomenon.
- Agree on a definition of the rebound phenomenon.
- Agree on key issues related to the rebound phenomenon in the design of studies evaluating new strategies or interventions.
- Consider when and to what extent rebound could be a public health problem.
- Consider approaches to ameliorate the effects of rebound in public health practice.