Post-exposure prophylaxis against Ebola virus: Arguments for expanding the role of monoclonal antibodies in a context of limited access

INTRODUCTION AND METHODS

While Ebola virus disease (EVD) remains a major threat, recent advances have led to the approval of several medical products, in particular the rVSV? G-ZEBOV-GP vaccine (Ervebo) and two monoclonal antibody treatments, mAb114 (Ebanga) and REGN-EB3 (Inmazeb). However, their use in post-exposure prophylaxis (PEP) remains poorly documented. Our narrative review of the literature and guidelines aims to assess the potential of the rVSV? G-ZEBOV-GP vaccine and monoclonal antibodies mAb114 and REGN-EB3 for PEP following high-risk exposure.

RESULTS

Very few studies have been conducted specifically to determine the efficacy of vaccines or monoclonal antibodies as PEP. Data from animals and humans suggest that the rVSV? G-ZEBOV-GP vaccine offers only limited protection as PEP, although it may reduce the severity of EVD if it occurs. None of the 34 individuals who have received the vaccine as PEP to date have developed EVD. A retrospective case-control study suggests an efficacy of only 16% against the occurrence of EVD when the vaccine is administered during a period compatible with PEP. In contrast, the monoclonal antibodies mAb114 and REGN-EB3, due to their immediate action through passive immunisation, appear to confer higher protection against the onset of EVD after high-risk exposure, with 100% survival in animal models, although human clinical data remain scarce with only 23 cases of use reported in PEP and no occurrence of EVD.

DISCUSSION AND CONCLUSION

Access to monoclonal antibodies for community members following high-risk exposure should be ensured, while optimising risk assessment criteria. Further research, particularly on the interaction between vaccination and antibody administration, is essential to determine the most effective PEP strategies. Finally, an emergency stockpile of monoclonal antibodies and improved contact tracing are essential to strengthen the response to epidemics. Despite the limitations of current data, monoclonal antibodies should be considered a priority option for PEP after high-risk exposure.