AREBO/BUDSEV: strengthening the diagnostic toolkit against Bundibugyo

AREBO (ANRS00963-R-PR) is a research project led by the Institut Bouisson Bertrand, under the supervision of Éric Delaporte, and by the National Institute for Biomedical Research (INRB) in the Democratic Republic of the Congo (DRC).

This project stems from a reallocation of funding from the EPAMAC project, which was originally dedicated to studying the clinical manifestations and long–term effects of mpox infection in Guinea, in order to contribute to the fight against Ebola Bundibugyo virus (BDBV) disease. It was designed in response to the ongoing outbreak in the DRC since May 2026, with the aim of providing a rapid response to diagnostic needs on the ground and sustainably strengthening diagnostic capacity in the DRC, both in central laboratories in Kinshasa and in decentralised laboratories.

Objectives of the AREBO project

The AREBO project aims primarily to strengthen the diagnostic toolkit available for BDBV in two areas:

• molecular tests
• serological tests (BUDSEV study)

In its first strand, dedicated to molecular tests, the project is notably involved in the evaluation of commercial ‘point-of-care’ molecular tests, including those suitable for BDBV or more broadly covering filoviruses, for example on platforms such as GeneXpert, RADIONE or equivalent. These tests are evaluated using a reference panel to determine their performance, particularly in terms of sensitivity and specificity, and to assess their suitability for operational deployment in the field.

A second strand of the project focuses on the development and provision of serological tests capable of detecting antibodies specific to various Ebola viruses, including BDBV. These tools should, in particular, enable the spread of the infection to be better documented, the immune response to be studied, and contribute to the monitoring and characterisation of those who have survived the infection. A serological study, the BUDSEV study, using the tests developed as part of the project, has begun in Ituri, one of the main hotspots of the BDBV epidemic.

Focus on the BUDSEV study

The BUDSEV observational serological study aims to characterise the humoral immune response against BDBV among survivors, suspected cases and medical and frontline workers in Ituri Province, DRC.

In particular, it aims to determine whether vaccination with Ervebo® (a live-attenuated Ebola Zaire virus vaccine developed by MSD Vaccines) can induce cross-protection against BDBV, by comparing the immune responses observed in vaccinated and unvaccinated individuals, particularly amongst survivors of BDBV infection, suspected cases, as well as healthcare and frontline workers.

Launched on 31 August 2026, the BUDSEV study covers three health zones in Ituri (Bunia, Nizi and Rwampara) and aims to recruit 540 participants over a two-month period.

The results will provide a better understanding of whether Ervebo®, originally developed against the Ebola Zaire virus, can also confer a certain level of protection against BDBV.

As of 17 September 2026, 410 individuals had been enrolled out of a total of 540 expected. Of these, 94 individuals had previously received at least one dose of the Ervebo® vaccine.