Response plan to pfhrp2 gene deletions, second edition

The emergence of P. falciparum parasites with deletions in the pfhrp2 and pfhrp3 genes in most malaria-endemic regions poses a significant biological threat to malaria control.  These parasites are undetectable by HRP2-based rapid diagnostic tests (RDTs) – the most commonly used test for malaria diagnosis – resulting in false-negative RDT results, which can have serious consequences for the management of malaria patients. Pfhrp2+/-pfhrp3 deletions have been reported in over 40 countries but have only reached prevalence levels requiring a change in RDT in smaller subset in South America in the Horn of Africa. Action is required on multiple fronts to address this challenge and stem both the spread and emergence of deleted parasites. 

The first edition of the response plan was published in 2019 and called upon relevant stakeholders to identify new biomarkers; improve the performance of non-HRP2 RDTs; undertake market forecasting; and strengthen laboratory networks to support the demand for using molecular characterization to determine the presence or absence of these gene deletions.

In January 2023, WHO hosted a technical consultation to address the threat of pfhrp2 gene deletions and outcomes of this meeting have informed this new edition of the response plan which in addition to incorporating new research findings, it draws upon country experiences and includes results of modelling exercises to predict the evolution of this threat and the implications for RDT markets. 

→ See also the “Master protocol for surveillance of pfhrp2/3 deletions and biobanking to support future research, second edition“