Patients cured of Ebola virus disease: rapid decline in antibody levels in patients treated with monoclonal antibodies

Ebola virus disease is a serious infection with a lethality rate ranging from 30% to 90% in the absence of treatment. Between 2018 and 2020, in the provinces of North Kivu, South Kivu and Ituri (DRC), the tenth Ebola epidemic was the longest and deadliest ever recorded to date in the country, and the second largest in the world, after the 2013-2016 epidemic in West Africa.

The experience gained from previous epidemics has led to the adoption of preventive measures and the implementation of new strategies to combat the virus. As a result, specific anti-Ebola drugs, in particular monoclonal antibodies, have improved patient care and survival. In this study, to better understand the long-term effects of these treatments, researchers assessed the humoral immune response² in survivors treated with anti-Ebola drugs during the tenth Ebola epidemic in the DRC.

“Ebola Victors”

Participants in the observational study, “Ebola Victors“, were recruited on the day of discharge from the Ebola Treatment Center (ETC) and followed for up to 12 months. Of the 787 survivors included in the study, the researchers studied the antibody response of 358 of them: on discharge, almost a quarter were seronegative for at least two antigens of the virus. Those who had received specific anti-Ebola treatments, in particular monoclonal antibodies (Ansuvimab), experienced a rapid decline in their antibody levels to the virus over time. These results raise many questions, notably concerning the impact of these antibodies on viral persistence in privileged immune sites, with a risk of relapse or persistent clinical manifestations (sequelae), and also on the risk of reinfection in these patients.

This study underlines the need for further research into the human reservoir of the Ebola virus, in order to better understand the factors involved in the persistence and resurgence of the virus, and thus develop drugs capable of eradicating it. From a public health point of view, it is important to continue monitoring people declared cured of Ebola virus infection, and to discuss the advisability of vaccinating them to help prevent any resurgence or reinfection. Finally, this study illustrates the importance of interventions during epidemic periods, combining three essential actions: care, research and the ability of teams to mobilize.

1- antibodies manufactured specifically to treat a disease
2- is characterized by the excretion in the serum of antibodies specific for a given antigen

Reference

Antoine Nkuba-Ndaye, Angele Dilu-Keti, Tamara Tovar-Sanchez, Mamadou Saliou Kalifa Diallo, Daniel Mukadi-Bamuleka, Richard Kitenge, Pierre Formenty, Anaïs Legand, François Edidi-Atani, Guillaume Thaurignac, Raphael Pelloquin, Placide Mbala-Kingebeni, Abdoulaye Toure, Ahidjo Ayouba, Jean-Jacques Muyembe-Tamfum, Eric Delaporte, Martine Peeters, Steve Ahuka-Mundeke.

Impact of Anti-Ebola virus monoclonal antibodies on endogenous antibody production in Ebola virus disease survivors in the Democratic Republic of the Congo: an observational cohort study, The Lancet infectious Diseases, 30 novembre 2023.