Current progress towards prevention of Nipah and Hendra disease in humans: A scoping review of vaccine and monoclonal antibody candidates being evaluated in clinical trials.

Objectives: Nipah and Hendra are deadly zoonotic diseases with pandemic potential. To date, no human vaccine or monoclonal antibody (mAb) has been licensed to prevent disease caused by these pathogens. The aim of this scoping review was to identify and describe all Phase I, II, and III clinical trials of vaccine candidates or mAbs candidates designed to prevent Nipah and Hendra in humans and to compare the characteristics of the vaccine candidates to characteristics outlined in the Target Product Profile drafted by the World Health Organisation as part of the WHO Research & Development Blueprint for Action to Prevent Epidemics.

Methods: We searched 23 clinical trial registries, the Cochrane Central Register of Clinical Trials, and grey literature up to June 2023 to identify vaccine and mAb candidates being evaluated in registered clinical trials. Vaccine candidate and trial characteristics were double-extracted for evaluation and the vaccine candidate characteristics were compared with the preferred and critical criteria of the World Health Organisation's Target Product Profile for Nipah virus vaccine.

Results: Three vaccine candidates (Hendra Virus Soluble Glycoprotein Vaccine [HeV-sG-V], PHV02, and mRNA-1215) and one mAb (m102.4) had a registered human clinical trial by June 2023. All trials were phase 1, dose-ranging trials taking place in the United States of America or Australia and enrolling healthy adults. Although all vaccine candidates meet the dose regimen and route of administration criteria of the Target Product Profile, other criteria such as measures of efficacy and reactogenicity will need to be evaluated in the future as evidence becomes available.

Conclusion: Multiple vaccine candidates and one mAb candidate have reached the stage of human clinical trials and are reviewed here. Monitoring progress during evaluation of these candidates and candidates entering clinical trials in the future can help highlight many of the challenges that remain.