Vector control for malaria prevention during humanitarian emergencies: protocol for a systematic review and meta-analysis

Introduction Humanitarian emergencies, of either natural or anthropogenic origins, are equivalent to major disasters, which can lead to population displacement, food insecurity and health system disruptions. Almost two-thirds of persons affected by humanitarian emergencies inhabit malaria endemic regions, particularly the World Health Organization (WHO) African Region, which currently accounts for 93% and 94% of malaria cases and deaths, respectively. As of late 2020, the United Nations Refugee Agency estimates there are globally 79.5 million forcibly displaced people, including 45.7 million internally displaced people, 26 million refugees, 4.2 million asylum-seekers and 3.6 million Venezuelans displaced abroad. Methods and analyses A systematic review and meta-analysis will be conducted to evaluate the impact of different vector control interventions on malaria disease burden during humanitarian emergencies. Published and grey literature will be systematically retrieved from ten electronic databases and three clinical trials registries. A systematic approach to screening, reviewing and data extraction will be applied based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Two review authors will independently assess full-text copies of potentially relevant articles based on inclusion criteria. Included studies will be assessed for risk of bias according to Cochrane and certainty of evidence using the GRADE approach. Eligible studies with reported or measurable risk ratios or odds ratios with 95% confidence intervals will be included in a meta-analysis. Sub-group analyses, including per study design, emergency phase, and primary mode of intervention, may be performed if substantial heterogeneity is encountered. Ethics and dissemination Ethical approval is not required by the London School of Hygiene and Tropical Medicine to perform secondary analyses of existing anonymous data. Study findings will be disseminated via open-access publications in peer-reviewed journals, presentations to stakeholders and international policy makers, and will contribute to the latest WHO guidelines for malaria control during humanitarian emergencies. PROSPERO registration number CRD42020214961. Strengths and limitations of this study ⇒ This will be the first systematic review and meta-analysis of the impact of different vector control interventions on malaria disease burden during humanitarian emergencies, providing a comprehensive global evidence summary that can be updated as new evidence emerges. ⇒ Inclusion of a broad range of study types will allow the identification of studies from a diverse range of humanitarian contexts. ⇒ By definition, humanitarian emergencies are unpredictable and volatile and consequently these settings can be restrictive with respect to study design, limiting the number of community-level randomised control trials with epidemiological outcomes which can be considered in this review. ⇒ Lack of a sensitive literature search strategy may result in a large number of titles and abstracts to screen initially.